Journal of Personality
and Social Psychology
Monograph Supplement
Volume 9, No. 2, Partj2

June 1968

ATTITUDINAL EFFECTS OF MERE EXPOSURE 1
ROBERT B. ZAJONC
University of Michigan
The hypothesis is offered that mere repeated exposure of the individual to a
stimulus object enhances his attitude toward it. By "mere" exposure is meanta condition making the stimulus accessible to the individual's perception.
Support for the hypothesis consists of 4 types of evidence, presented andreviewed: (a) the correlation between affective connotation of words andword frequency; (b) the effect of experimentally manipulated frequency of
exposure upon the affective connotation of nonsense words and symbols; (c)the correlation between word frequency and the attitude to their referents;(d) the effects of experimentally manipulated frequency of exposure on attitude. The relevance for the exposure-attitude hypothesis of the exploration
theory and of the semantic satiation findings were examined.

exposure" is meant a condition which justmakes the given stimulus accessible to the individual's perception.
Even though the hypothesis seems to be in
A mysterious student has been attending a class atOregon State University for the past two months conflict with such celebrated laws as familienveloped in a big black bag. Only his bare feet arity breeds contempt and absence makes theshow. Each Monday, Wednesday, and Friday at heart grow fonder, it is not particularly origi11:00 A.M. the Black Bag sits on a small table near nal or recent (Fechner, 1876, pp. 240-243;
the back of the classroom. The class is Speech 113—
basic persuasion. . . . Charles Goetzinger, professor James, 1890, p. 672; Maslow, 1937; Meyer,of the class, knows the identity of the person inside. 1903; Pepper, 1919). The foremost proponent
None of the 20 students in the class do. Goetzinger of this hypothesis, the advertising industry,
said the students' attitude changed from hostility has always attributed to exposure formidable
toward the Black Bag to curiosity and finally to advertising potential. But—apparently, in refriendship [italics added].
spect for the law of enhancement by associaThis monograph examines the general hy- tion—it seldom dared to utilize mere exposure.
pothesis implied by the above phenomenon: The product, its name, or its hallmark ismere repeated exposure of the individual to a always presented to the public in contiguity
stimulus is a sufficient condition for the en- with other and always attractive stimuli, comhancement of his attitude toward it. By "mere monly females, exposed more boldly than the1
This work was supported by the National Insti- product itself. At the same time, however, thetute of Mental Health, Grant MH 12174. I wish to advertising industry also likes to warn against
thank Christine Linder, Dik van Kreveld, and James owerexposure, relying, it would appear, on the
J. Taylor for their invaluable assistance in carrying above law of familiarity (Erdelyi, 1940;
out various phases of the experimental work. I am Wiebe, 1940).
also indebted to Elinore Cottrell and Robert P.
It isn't altogether clear just what evidence
Weeks for making their students available as judges
supports these advertising principles. And
and subjects.
On February 27, 1967, the Associated Press
carried the following story from Corvallis,
Oregon:© 1968 by the American Psychological Association, Inc.

ROBERT B. ZAJONC
direct evidence that attitudes are enhanced bymere exposure or mere contact with the stimulus object is scant. Moreover, it is the productof antiquated methods, and almost all of it
concerns music appreciation (Downey &Knapp, 1927; Krugman, 1943; Meyer, 1903;
Moore & Gilliland, 1924; Mull, 19S7; Verveer, Barry, & Bousfield, 1933; Washburn,Child, & Abel, 1927). The problem of attitudinal effects of social contact and interaction has also been of some interest in the
study of interracial attitudes (Cook & Selltiz,
1952). But these studies have invariably examined the effects not of mere perceptual exposure of people to each other, but of processes considerably more complex: prolonged
social interaction, group interdependence, cooperation, etc. (Deutsch & Collins, 1951;
Kramer, 1950; MacKenzie, 1948; Wilner,
Walkley, & Cook, 1952). Although the independent variables in these studies have generally been featured under the labels "contact"and "exposure," the effects they report cannot, because of confounding with a multitudeof other events (and with reinforcement inparticular), be regarded as produced alone bycontact or exposure. Thus, it has been known
for some time that social interaction enhances
the attitudes of interactors toward each other(Bovard, 1951; Festinger, 1951; Homans,
1961; Newcomb, 1963). But it is not known
just what contribution to the relationship between social interaction and attitudes ismade by mere exposure on the one hand, andby the variety of psychologically significant
processes that necessarily accompany mere exposure during the course of social interaction,on the other.
The main empirical support for the exposure
hypothesis comes, therefore, not from workon interaction, interracial attitudes, or attitudes in general, but from an entirely different and seemingly unrelated area of research.
It comes from some recent work on word frequencies. This recent research shows that
there exists an intimate relationship between
word frequency and meaning. And this relationship, in my opinion (for which I shalllater present support), may be a special caseof the more general relationship between mere
exposure and attitude enhancement.
The strength and pervasiveness of the rela-tionship between word frequency and meaning—the evaluative aspect of meaning, in particular—is truly remarkable. For, if there isany correspondence between the frequency
with which words are used and the actual
preponderance of the things and events forwhich these words stand, then we may congratulate ourselves on living in a most happy
world. According to the Thorndike-Lorgecount (1944), the word "happiness" occurs
761 times, "unhappiness" occurs only 49
times. "Beauty" is to be found at least 41
times as often as "ugliness," and "wealth"outdoes "poverty" by a factor of 1.6. We"laugh" 2.4 times as often as we "cry"; we"love" almost 7 times more often than we"hate"; we are "in" at least 5 times more
often than we are "out"; "up" twice as often
as we are "down"; much more often "successful" than "unsuccessful"; and we "find"things 4.5 times more often than we "lose"
them—all because most of us are "lucky"(220) rather than "unlucky" (17).
We have all the reasons in the world to be"happy" (1449) and "gay" (418) rather than"sad" (202) and "gloomy" (72), for things
are 5 times more often "good" than "bad,"almost 3 times more often "possible" than
"impossible," and about five times more
"profitable" than "unprofitable." That is, perhaps, why "boom" and "prosperity" outdo"recession" by a factor of just about 30,"abundance" outdoes "scarcity" by at least
3:1, and "affluence" is 6 times more prevalent than "deprivation." Catering to our
corporeal sensibilities, things are 3 times more
often "fragrant" than they are "foul," 12times more often "fresh" than "stale," andalmost 7 times more often "sweet" than"sour," and everything that can be filled isthree times as often "full" as it is "empty." If
we have anything, we have "more" of it 6
times more often than we have "less" of it,2
and 3 times more often "most" of it than"least" of it. And those things that we haveso frequently more of are 5 times more often"better" than they are "worse," 6 times
more often "best" than "worst," and 4 times
more often "superior" than "inferior." Still,2
N.B. The more-less ratio in this text is 7:1 up
to now.

THE ATTITUDINAL EFFECTS OF MERE EXPOSURE
they "improve" at least 25 times as often as
they "deteriorate."
These examples suffice to convince one thatthe world represented by a one-to-one correspondence with word frequencies is as unreal
as it is spectacular. Bitterly aware of it,
Sartre (1964) confessed in his autobiography," . . . as a result of discovering the world
through language, for a long time, I took
language for the world [p. 182]."
But, while they are unfaithful in representing reality, word frequencies are extraordinarily accurate in representing real values:
words that stand for good, desirable, and preferred aspects of reality are more frequently
used.
It isn't entirely clear who discovered thisremarkable relationship between word frequency and the evaluative dimension of word
meaning. Postman (1953) seems to be one of
the early workers to note its generality, while
Howes and Solomon (1950) observed in theircritique of McGinnies' (1949) perceptual defense experiment that the so-called "taboo"words he used as stimuli are particularly infrequent. However, the first systematic research effort that demonstrates the wordfrequency-word-value relationship is due toJohnson, Thomson, and Frincke (1960).
These authors were the first, I believe, to collect empirical data showing that words with"positive" meaning have higher frequency
counts than words with "negative" meanings.
They have also gathered experimental evidence showing that the repeated use of a nonsense word tends to enhance its rating on the
good-bad scale of the semantic differential.
Johnson, Thomson, and Frincke (1960) havenot tried to explain either of these two aspects of the frequency-value relationship, being primarily concerned with its implications
for the study of word-recognition thresholds.
This paper examines the frequency-value
relationship, proposing that it is considerably
more pervasive and general than implied by
the Johnson-Thomson-Frincke results, andthat it is, moreover, a special case of abroader and more basic phenomenon: the enhancement of attitudes by mere repeated exposure. I shall first review evidence on thecorrelation between word frequency and wordvalue, and between stimulus frequency andattitude. Experimental evidence on these two
relationships, and on the likely causal direction, will then be examined.
Word Frequency-Word Value: Correlational
Evidence
Johnson, Thomson, and Frincke (1960) obtained correlations of .63, .40, and .38 between the L-count (Thorndike & Lorge, 1944)
and the good-bad scale values for three samples of randomly chosen words. In a further
attempt, they constructed 30 pairs, each consisting of one frequent and one infrequentword. These pairs were given to a group of
subjects with the instructions to "encircle themost pleasantly toned word of each pair." In
87% of the pairs the majority of subjects
endorsed the more frequent word. Finally, 64
nonsense syllables of low, medium, and highassociation were rated by a group of subjects
on the good-bad scale of the semantic differential. Johnson, Thomson, and Frincke reported a clear relationship between association
value and "goodness" ratings. The rationaleof this study invoked the assumed relationshipbetween association of the given nonsense
syllable and the probability of occurrence ofthe corresponding letter combination in meaningful words (Underwood, 1959).
In an attempt to examine the generality ofthis phenomenon, we studied the evaluationsof 154 antonym pairs. First, a large pool ofantonym pairs was amassed. From this poolall symmetric8 pairs were chosen in the following manner. For each antonym pair 10
judges, 1 at a time, were asked to give theantonym of one member of the pair. Tenother judges—independently of the first 10—
were asked to give the antonym of the other3
One finds in the course of this endeavor that theantonymic relation is seldom symmetric. According
to the standard sources, if Y is listed as the antonymof X, then chances are that not X but Z is listed as
the antonym of V. For instance, in the 1960 edition of Webster's New Collegiate Dictionary, "extend" is given as the antonym of "contract." Looking
up "extend" we find, however, that its antonym is"reduce." The antonym of "reduce," on the other
hand, is "increase." The antonym of "increase" is"decrease," the antonym of "decrease" is "amplify,"
the antonym of "amplify" is "condense," and theantonym of "condense" is "expand." We can ultimately close the circle, because "contract," according
to this source, is the antonym of "expand."ROBERT B. ZAJONCTABLE 1SEMANTIC PREFERENCE AND FREQUENCY OF 154 ANTONYM PAIRS%
Preferredagree- alternative
(a)
ment
100
100
100
100
100
100
100
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
99
98
98
98
98
98
98
98
98
98
98
98
98
98
98
98
98
98
98
98
98
98
98
98
97
97
97
97
97
97
97
97
97
97
97

197

97
97
97
[97
96

able
attentive
betterencourage
friendly
honestpossible
advancebest
clean
comfortablefavorable
goodgrateful
peacepresentpure
responsible
rewardrightsmile
tolerant
victoryadd
advantageagreeable
capabledesirablefindfortunate
forwardfriendhighhonorable
kind
legal
life
love
maturemoral
pleasant
politereliable
successvalidvoluntaryadequate
competent
foundimportantlikelyonpatiencepatient
patiently
popularpositive
profitablepromoteremembersatisfactory
willingly
above

Nonpref erredalternative (6)Frequencyof (a)

Frequencyof (Wunableinattentive
worse
discourage
unfriendly
dishonest
impossible
retreatworst
dirty
uncomfortableunfavorable
bad
ungratefulwarabsentimpureirresponsible
punishment
wrong
frown
intolerant
defeatsubtract
disadvantage
disagreeable
incapable
undesirable
lose
unfortunate
backward
enemy
low
dishonorable
unkindillegaldeath
hate
immature
immoralunpleasant
impolite
unreliable
failureinvalidinvoluntary
inadequate
incompetent
lost
unimportantunlikelyoff
impatience
impatientimpatiently
unpolular
negative
unprofitabledemoteforgetunsatisfactory
unwillingly
below

930
49
2354
205
357
393

239
4
450
147
19
41
459
105
292
221
112
25

1289

452
1850

781
348
93

5122

194
472

1001

13

1118

404
58
176
160
2698
136
736
2553

65
4
30
80
890
216
13
166
6
41
43
30
42
593
108
139
883

1674

1224

58

8
34
34
815
756
17
19
114
3
9
262
56
26
59
23

1075

197
267
154
3874
2143

42
118
2018

1521

180
4804
5129

91
272
457
115
78
573
22
28
95
69
2892
1130

364
30224
139
392
85
418
92
57
90
1682

154
66
941

1074

40
25
3644
39
79
82
12
28
12
2
882
32
13
529

%
Preferredagree- alternative
(a)
ment

Nonpreferredalternative (&)

active
early
front
full
live
presence
probablerational
reasonable
resolutely
strongsucceedsuperior
timelyacceptdirectincludeincreasemostpractical
regularly
rich
wealthapproveconscious
leaderobedient
togetheragreement
certainfirst
major
normalregularunselfish
upwards
wide
more
now
up
upwardvisibleyes
alwaysfamiliarmaximum
optimism
agreenecessary
over
sweet
whole
light
deep
smoothwhite
inindependent
fast
comedyfastenday
drypassive
late
back
empty
die
absence
improbableirrational
unreasonableirresolutely
weak
fail
inferior
untimely
rejectindirect
excludedecrease
least
impracticalirregularlypoor
povertydisapprove
unconscious
followerdisobedientapartdisagreement
uncertain
last
minor
abnormalirregular
selfishdownwards
narrow
less
then
down
downward
invisiblenoneverunfamiliar
minimum
pessimism
disagreeunnecessary
under
sour
part
dark
shallow
rough
black
out
dependent
slow
tragedy
unfasten
night
wet

96
96
96
96
96
96
96
96
96
96
96
96
96
96
95
95
95
95
95
95
95
95
95
94
94
94
94
94
93
93
93
93
93
93
93
93
93
92
92
92
92
92
92
91
91
91
91
90
90
90
90
90
89
88
88
86
85
85
84
83
83
79
78

Frequencyof (a)

Frequencyof (6)

186

29
2859
6587
395
1079
163
14
9
56
4
276
620
40
6
51
23
38
86
1259
12
5
857
146
45
116
45
4
276
21
107
3517
83
43
44
137
40
391
1357
10208
5534
27
74
11742
5715
39
86
11
38
107
2961
102
1585
1005
104
294
1083
13649
18
434
189
16
3385
319

1022
1094
1129
4307

277
64
33
155
30
770
264
166
27
667
416
533
781
3443
340
122
656
243
171
299
373
70
1835

143
800
5154

366
335
340
32

9
593

8015
7665
11718

111
110
2202
3285
345
43
28
729
715
7520
679

1663
2387
881
346
2663
75253
134
514
126
142
4549
592

THE ATTITUDINAL EFFECTS OF MERE EXPOSURE
TABLE I—Continued%

Preferredagree- alternative (a)
ment

78
78
77
74
72
72
70
70
68
68
67
67
65
64

long
unshakenusually
upstairs
innerinterior
near
unlimited
insidewrap
infiniteinternal
cominginformal

Nonpreferredalternative (i)shortshakenunusually
downstairs
outerexterior

far

limitedoutsideunwrapfiniteexternal
going
formalFrequencyof (a)

Frequencyof (6)

5362

887

6
718
314
143
185

1338

43
656
293

71

36
1486

64

83
91
226
97
48

1835

67
921
17
2
26
4623

166

Preferredagree- alternative (a)
ment
CO

63
63
61
59
59
58
58
57
55
55
55
54
52
51

Nonpreferredalternative (6)question
women
different
same
inwardoutwardman
women
husbandwife
usual
unusualoffensedefensehot
cold
importexpertinwardly
outwardly
inconspicuous conspicuous
work
play
mortalimmortal
answermen

Frequencyof (a)

Frequencyof (6)

2132
3614
1194

2552
1747

7355
1788

2431
1668

1006

1092

2606

2720

43

516
86

86
32
33
54

1302

54

273
223

88
33
59
26

member of the pair. Only those pairs were which there is relatively little agreement. For
retained about which the 20 judges showed pairs with agreement greater than 95% (i.e.,
unanimous agreement with the dictionary the upper half of the list) there are only six
sources. A list of 154 antonym pairs was thus reversals out of the 77 possible. It is signifiobtained. These were given to 100 subjects, cant, moreover, that in three of these six
all college students, for judgments as to which antonym pairs the less desirable member
member had "the more favorable meaning, (which in these cases is the more frequent
represented the more desirable object, event, one) has more meanings and linguistic uses
state of affairs, characteristic, etc." A differ- than the more desirable one. "Invalid" means
ent random order of the antonym pairs was both "not valid" and "cripple," but "valid"
given to each subject, and the lateral positions is just "valid." "Yes" is an adverb, but "no"of the members of each pair were reversed at is an adverb and an adjective. And "front"
is a noun, a verb, and an adjective, while
random for half of the group.
Table 1 shows the list of these 154 antonym "back" is all that and an adverb to boot.
Toward the end of the list where the desirpairs, together with the "desirability" and thefrequency data (the Thorndike-Lorge L- ability preferences are divided fairly evenly
count). The preferred member of each pair is between the two members of the antonym
always listed first. The "desirability" figures pairs, the frequencies of the two antonyms
are simply the percentages of subjects choos- often are nearly the same. "Play" is preferred
ing the left member of the pair as the pre- to "work" only by a majority of two (a curious commentary on the contemporary college
ferred alternative.
It is of some interest, however incidental, population!), and the respective frequency
that there is considerable agreement about counts of these antonyms are 2606 and 2720.
desirability of the meanings. On half of the The "hot-cold" preference is 55 to 45 anditems the agreement exceeded 95%. Agree- their frequency counts 1006 and 1092. The
ment is high even for words which are not "husband-wife" preference is 58 to 42 andgenuinely evaluative. For instance, 97 of the their respective frequencies, 1788 and 1668.
Three antonym items about which agree100 students preferred "on" to "off," 98 preferred "add" to subtract, 96 "above" to ment was complete or nearly complete show a"below," and 92 "upward" to "downward." curious pattern of results. They are "goodFor the overwhelming majority of the items bad" (5122:1001), "better-worse" (2354:
the preferred word is also the more frequent 450), and "best-worst" (1850:292). Since
one. Only 28 of the 154 antonym pairs (18%) "better" is presumably better than "good,"
show a negative relationship between fre- "worse" worse than "bad," and since "best"
quency and desirability. Moreover, these "re- is presumably better than "better," andversals" occur primarily for antonym pairs on "worst" worse than "worse," we would expect

ROBERT B. ZAJONC
the greatest separation between the frequencies of "best" and "worst," smallest between
the frequencies of "good" and "bad," andmedium between the frequencies of "better"and "worse." Since absolute differences are
deceiving, we best take the ratios of the frequencies, which are 6.34, 5.23, and 5.12 for"best-worst," "better-worse," and "good-bad,"respectively. It is indeed the case that thefrequency ratios increase from "good-bad" to"best-worse." However, if frequency reflects"desirability," we would also expect the frequency of "best" to exceed the frequency of"better," and that of "better" to exceed thefrequency of "good." In fact, however, "good"
is more frequent than "better," and "better"more frequent than "best!" But is "better"better than "good?" In an extensive study of
meanings Hosier (1941) found that "good"
was consistently rated as better than "better."Startling as this may appear to grammarians, it ispsychologically sound, since GOOD is a positive assertion, whereas BETTER implies comparison with somestandard which might, in many cases, be itself unfavorable. Compare the often heard comment, "Heis getting better, but he is still far from good" [p.
134].

For purposes of comparison the frequencies
of French, German, and Spanish equivalentsof some of the antonyms examined are given
in Table 2 below. Systematic data on indigenous desirability ratings are unfortunately
not available, but it would be surprising if
the French, German, and Spanish judgments
differed from those obtained in the UnitedStates. An informal inquiry among foreign
visitors marshalled a good deal of support forthis conjecture. Comparing the data in Tables
1 and 2, the agreement is rather striking. In
15 out of the 44 cases the frequency relationin the antonym pairs is the same in the three
foreign languages as in English: the morefavorable item is more frequent, a result exceeding chance expectation by a large margin.
The results in Table 2, furthermore, give aready expression to our favorite ethnic prejudices. The relatively low frequency of the
two Romance equivalents of "early" and thehigh frequency of these equivalents of "late,"in comparison to their Germanic counterparts,
make generalizations about national character
tempting, as does the relatively low frequencyof the German equivalent of "reward." Theforeign equivalents of answer-question, hotcold, import-export, peace-war, etc., however,show patterns of differences that may reflect
more than superficial linguistic idiosyncrasies.
Several questions can immediately be raised
about the above results. First, are these figures up to date? The Thorndike-Lorge countis based on samples of material published during the late twenties and the early thirties.
The German equivalents come from a source
dating to the late 19th century (Kading,1898). The French count was published in
1929 (Van der Beke, 1929), and the Spanish
in 1927 (Buchanan, 1927). Secondly, dothese results reflect general verbal habits?
Word counts are based on printed material
alone. Do people show the same linguistic
predilections in ordinary speech as they doin writing? Admittedly, both questions indicate caution in generalizing from the above
results. But this caution needn't be excessive.
Howes (1954) has recently asked Harvard
and Antioch undergraduates to estimate theprobabilities of various words. The correlations between the students' estimates of several word samples and the L-count of theThorndike-Lorge source varied around .80.
There is also evidence from word association
studies showing that word counts do reflect
general verbal habits of the population. A
word which has a high frequency of occurrence in print is also a highly probable associate. The association norms to 200 words
were recently collected by Palermo and Jenkins (1964) from a sample of 4,500 school
children and college students in Minneapolis.
The list of the 200 stimulus words representsa systematic sample of verbs, nouns, pronouns, adverbs, adjectives, participles, etc.,
all having fairly high frequency on the Thorndike-Lorge counts. Since in the word association task each subject makes one response toeach stimulus word, Palermo and Jenkins
collected from their subjects 900,000 word
responses. Among them "good" occurred 4890
times, "bad" only 1956. The response "right"
was given 477 times, the response "wrong"
only 100 times. "Full" was found 431 times
among the associations, "empty" only 62
times. "Strong" was given 557, "weak" 96
times. "Together" occurred 575 times, "apart"THE ATTITUDINAL EFFECTS OF MERE EXPOSURE
TABLE 2FREQUENCY RANKS OP ENGLISH, FRENCH, GERMAN, AND SPANISH ANTONYM PAIRSEnglishFrenchable (3)unable (9)accept (3)reject (9)active (6)passive (14)answer (2)question (3)better (2)worse (4)certain (2)uncertain (9)capable (3)incapable (4)accepter (2)rejeter (5)clean (3)dirty (7)comedy (9)tragedy (9)comfortable (5)uncomfortable (11)day (2)night (2)direct (3)indirect (12)dry (3)wet (4)early (2)late (2)fast (2)slow (3)find (2)lose (3)friend (2)enemy (3)full (2)empty (4)good (2)bad (2)high (2)low (2)hot (2)cold (2)husband (3)wife (3)import (7)export (11)increase (3)decrease (8)propre (2)sale (7)comedie (6)tragedie (9)a 1'aise (4)inconfortable (9)jour (2)nuit (2)direct (6)indirect (12)sec (3)mouil!6 (5)t6t (3)tard (2)vite (2)lent (4)trouver (2)perdre (2)ami (2)
ennemi (2)plein (2)vide (4)bon (2)
mauvais (2)haut (2)bas (2)chaud (3)froid (3)mari (3)femme (2)importation (11)exportation (10)augmentation (10)reduction (11)independent (7)ddpendent (?)
vie (2)
mort (2)clair (3)sombre (3)independent (6)dependent (14)life (2)death (2)light (2)dark (2)actif (6)passif (?)
reponse (4)question (2)meilleur (2)pire (S)certain (2)incertain (10)Germanfahig (4)unfahig (11)annehmen (2)ablehnen (5)tatig (S)untatig (?)
Ant wort (3)Frage (2)besser (2)schlechter (?)
sicher (2)unsicher (9)sauber (9)schmutzig (12)Komodie (9)tragodie (11)bequem (S)unbequem (10)Tag (2)Nacht (2)direkt (3)indirekt (8)trocken (S)nass (9)frtih (2)spat (2)schnell (2)langsam (3)finden (2)verlieren (2)Freund (2)Feind (2)voll (2)leer (4)gut (2)schlecht (3)hoch (2)niedrig (4)heiss (S)kalt (3)Mann (2)Frau (2)
Einfuhr (11)Ausfuhr (12)Vermehrung (6)Verminderung (11)selbststiindig (4)abhiingig (6)Leben (2)
Tod (2)hell (4)dunkel (3)Spanishcapaz (3)incapaz (7)acceptar (3)rechazar (S)activo (6)pasivo (10)respuesta (4)pregunta (4)mejor (2)peor (2)cierto (2)incierto (9)limpio (3)sucio (6)comedia (4)tragedia (8)coniodo (7)incomodo (10)dia (2)
noche (2)directo (4)indirecto (8)seco (3)mojado (6)temprano (4)tarde (2)pronto (2)lento (4)encontrar (2)perder (2)amigo (2)enemigo (2)lleno (2)vacio (4)buen (2)mal (2)
alto (2)bajo (2)caliente (5)frio (2)esposo (2)esposa (2)importaci6n (?)
exportaci6n (13)aumento (5)diminuci6n (?)
independiente (S)dependiente (9)vida (2)muerte (2)claro (2)
obscuro (2)ROBERT B. ZAJONCTABLE 2— Continued
Englishlife (2)die (2)long (2)short (2)love (2)hate (4)more (2)less (2)near (2)far (2)peace (3)war (2)
positive (9)negative (11)possible (3)impossible (5)presence (4)absence (7)reward (6)punishment (6)right (2)wrong (3)strong (2)weak (3)sweet (2)sour (9)together (2)apart (4)victory (5)defeat (7)wealth (4)poverty (7)white (2)black (2)wide (2)narrow (3)Frenchvivre (2)mourir (2)long (2)court (3)aimer (2)hair (6)plus (2)moins (2)pres (3)loin (2)paix (3)guerre (3)positif (6)negatif (11)possible (2)impossible (3)presence (2)absence (5)recompense (6)punition (12)juste (2)faux (3)fort (2)faible (3)doux (2)amer (4)ensemble (2)s6par6 (2)victoire (4)defaite (8)richesse (5)pauvrete (12)blanc (2)noir (2)large (2)etroit (3)Germanleben (2)sterben (2)lang (2)kurz (2)lieben (2)hassen (6)mehr (2)weniger (2)nah (2)fern (2)Friede (3)Krieg (2)positiv (8)negativ (?)
moglich (2)unmoglich (3)Anwesenheit (9)Abwesenheit (9)Anerkennung (S)Strafe (4)richtig (2)falsch (3)stark (2)schwach (3)suss (4)sauer (9)zusammen (2)getrennt (3)Sieg (4)Niederlage (8)Vermogen (4)Armut (10)weiss (2)schwartz (3)breit (4)schmal (6)Spanishvivir (2)morir (2)largo (2)corto (3)amar (2)odiar (7)mas (2)
menos (2)cerca (2)lejos (2)paz (2)
guerra (2)positive (7)negative (7)posible (2)imposible (2)presencia (3)ausencia (4)premio (4)castigo (4)justo (3)mal (2)
fuerte (2)debil (4)dulce (2)amargo (4)junto (2)separado (3)victoria (5)derrota (9)riqueza (3)pobreza (S)bianco (2)negro (2)ancho (3)angosto (8)Note.—The figures in brackets indicate frequency ranks: (1) means that the word is among the 500 most frequent words, (2)that it is among the 1000 most frequent words, (3) that it is among the 1500 most frequent words, etc. The source of these counts
is Eatoniton (1940).

29 times. "Light" was a response 8655 times(N.B., some subjects must have given it morethan once), "dark" 4274 times. But as in thecase of the Thorndike-Lorge count, "front"
occurred 22 times, while "back" occurred 265
times; "rich" was given 36 times, while "poor"
was a response 95 times. "Near" was given
981 times, "far" 1218. "Coming" was given
166 times, "going" 714 times. And, as in Lcount, "play" and "work" showed 791 and957 occurrences, respectively.
However, the best evidence about the relationship between the individual's verbal hab-its and the evaluative aspect of meaning isfound in a recent study by Siegel,* although
it wasn't the purpose of her study to explore
this relationship. Siegel's experiment dealt
with the effects of verbal reinforcement on theemission of words differing in affective connotation and in frequency. Eighteen six-letterwords of known frequencies and previously
judged on the good-bad and the pleasantunpleasant scales were selected from a larger* Siegel, Felicia S. Effects of word frequency andaffective connotation on verbal responding duringextinction. (Mimeo)

THE ATTITUDINAL EFFECTS OF MERE EXPOSURE
sample. Six of these words were of high frequency (100 and more in 1 million), six of
medium (20 to 30), and six of low frequency(1 to 5). Within each frequency class twowords were previously judged to be good, twoneutral, and two bad. Three groups of subjects, other than those involved in the affective judgments, participated in the experiment, each having to deal with six words ofthe same frequency. The procedure consistedof presenting the subject with the list of six
words, all high, medium, or low in frequency,
depending on the condition in which he was in,and giving him at the same time a stack ofcards on which appeared illegible six-letter"words." Ostensibly, each card contained oneof the six words in the subjects' list. Actually,the "words" consisted of random sequencesof six letters, printed over several thicknessesof paper and one carbon. Their legibility was
further reduced by placing each card in anonionskin paper envelope. The subjects' task
was to "read" or to guess what word appearedon each card. Of interest for the present purposes are the first SO trials which served to establish operant rate, and during which, ofcourse, no reinforcement of any sort was given.
Table 3 shows data on the guessing behaviorof Siegel's subjects as a function of word frequency and affective connotation. Reported ineach cell is the average number of times aword of a given frequency and affective value
was used as a guess during the SO operant
trials. Since there are six words to choose
from, 8.33 represents a chance response rate.
It is clear, however, that both frequency andaffective connotation displace response rateaway from the chance level. High frequency
seems to result in overcalling, and low freTABLE 3
FREE RESPONSE EMISSION AS A FUNCTION or
WORD-FREQUENCY AND WORD VALUE"
Word frequency
...

.

.

Good
MediumBad
X

Low

Medium

High

7.43
6.28
6.28
6.66

9.43
8.57
5.86
7.95

9.68
8.71
7.71
8.70

' From Siegel, I960.

8.8S
7.85
6.61

quency in undercalling. But it is striking todiscover that affective connotation had aneven stronger effect on response emission, themarginals for that variable showing a somewhat greater range of differences.
Some words in the language have primarily
an evaluative function. These words should
show the frequency-value relationship withparticular clarity. Several instances of thisrelationship are examined.
Let us first consider the scales of the Semantic Differential (Osgood, Suci, Si Tannenbaum, 1957). We have chosen only thosescales which have high and relatively pureloadings on one of the three main factors,
evaluation, potency, and activity. Table 4shows the polar opposites of these scales, together with their frequencies according to theThorndike-Lorge L-count. The left-hand polar
opposites in the three columns are the favorable, potent, and active ends of the scales. It
is significant that among the 19 evaluative
scales the favorable polar opposite has always
higher frequency than the unfavorable opposite. For the scales which do not load high on
the evaluative factor the high frequencies are
divided fairly evenly among the potent andnonpotent opposites. In 9 of the IS potency
scales the highly potent end of the scale ismore frequent. In 3 of the 8 activity scales
the active polar opposite is more frequent.
There are two other instances of a highcorrelation between frequency and value foradjectives. The first comes from the work by
Gough (1953). Gough has given the items of
his Adjective Checklist to 30 judges who rated
each adjective for favorability. The mostfavorable and the least favorable quartiles ofGough's checklist are reported in his publication. The average word frequency of theupper quartile is 140, and of the lower quartile 48. The second illustration comes fromdata collected by Anderson (1964). A list of
SSS adjectives was recently used by Anderson
in his work on impression formation. The list
was constructed out of a large sample ofitems. The 555 selected items were given byAnderson to a group of 100 subjects with the
instructions to rate on a 7-point scale "howmuch you yourself would like the person described by that word." We have simply computed the correlation between these likeabil-TABLE 4
POLAR OPPOSITES OF THE SEMANTIC DIFFERENTIAL
AND THEIR FREQUENCIES
Evaluative factor
beautiful
clean
fair
fragrant
goodgrateful
happy
harmonious
honestkind
nicepleasant
positive
reputablesacredsuccessful
sweet
true
wise

ugly
dirty
unfairfoulbad
ungrateful

987
781
561
66

178
221
59
39

5122

1001

sad

194

1449

dissonantdishonest
cruel
awful
unpleasantnegative
disreputableprofaneunsuccessful
sour
false
foolish

26
393

1521

630
457
92
23
102
352
679

1711

420

13
202
9
41
165
370
114
28
21

13
14
102
209
223

REQUENCY PER 4,SOO,OOO WORDS (L-COUNT
—
01
01
01
01
O
O
O
O
O 0
0
O
O

ROBERT B. ZAJONC

10

s

^s

s

1

s

.>
—<

s

/X^
r- 83

o-

I.OI2.013.OI- 4.01- 5.OI2.OO
3.OO 4.OO
5OO
6.OO
AVERAGE FAVORABILITY RATING

I.OO

FIG. 1. Average frequencies of 555 adjectives rated
for favorability. (Based on data from Anderson,
1964.)

Potency factor

frequencies are plotted for six categories ofadjectives in increasing order of favorability.
Considering that the reliabilities of the Thorn1909
dike-Lorge count and of Anderson's favor1005
680
ability ratings are less than perfect, the co1697
1818
efficient of correlation of .83 is particularly
40
54
99
91
impressive.
294
346
Miller, Newman, and Friedman (19S8)
248
37
9
119
have shown that word frequency is a negative
770
276
function of word length. The problem im22
7
mediately arises, therefore, as to which of
646
443
391
593
these two variables is critical for word value
and word meaning. In order to examine thisActivity factor
possible confounding between frequency andword length, the above correlation was recom434
514
activepassive
puted holding the number of letters constant.
1005
brightdark
645
267
excitablecalm
7
No appreciable change in the previously ob514
434
slow
fast
tained coefficient was observed.
21
2
heretical
orthodox
The relationship between word frequency
1092
1006
hot
cold
48
rash
37
cautious
and word length is generally explained in
289
sharp
324
dull
terms of the principle of least effort. Words
that require considerable effort in writing andinspeech are less likely candidates for use.
ity ratings and the logarithm of the Thorn5In
an attempt to control for effort Frincke
dike-Lorge L-count. Figure 1 shows thisandJohnson (1960) have asked subjects torelationship graphically, where means of log
choose the "most pleasantly toned word" from5
Items for which there was no frequency informa- each of 108 homophone pairs. The greatest
tion in the Thorndike-Lorge count were not included majority of these pairs consisted of words ofin computing this coefficient. These items were prithe same length, and all pairs, of course, conmarily of the hyphenated form, such as open-minded,
good-humored, well-spoken, fault-finding, ultra-criti- sisted of words that required the same effort
in uttering them. Out of 3,132 possible choices,cal, wishy-washy, etc.
bass
brave
deep
hard
heavy
large
masculine
matureroughruggedseverestrongtenacious
thick
wide

treblecowardly
shallow
soft
light
small
feminine
youthfulsmoothdelicatelenient
weakyielding
thin
narrow

28
216
881

17
26
104
549

THE ATTITUDINAL EFFECTS OF MERE EXPOSURE
the more frequent member of the pair waschosen 1,836 times.
Dixon and Dixon (1964) have given a listof 200 verbs (in past-tense form) to 60 female and 60 male judges who rated them onan 11-point good-bad scale. The instructions
were to rate what "kind of impression thesubject thought a psychologist would get ofhim when he used each verb in a sentence."
These impression ratings have correlations
with log frequencies (the Thorndike-Lorge Lcount) equal to .48 for females and to .50
for males. But it must be pointed out thatthese coefficients represent correlations severely attenuated by unreliability of the frequency variable. The Thorndike-Lorge countlists verbs in the present-tense form. If an
adjectival form of the verb exists, then it isalso listed. In our own research, in computing
correlation coefficients, only the present-tense
frequencies were used.
Miron (1961) had American and Japanese
subjects rate a sample of three-element phonetic combinations on various scales of the
Semantic Differential. The subjects also rated
these stimulus materials for their familiarity.
It is interesting that the correlations between
familiarity and the composite of evaluative
scales were .59 and .50 for the American and
the Japanese samples, respectively. But thecorrelations of familiarity with the compositesof the potency and activity factors were low
and negative.
As a final example of the relationship between word frequency and the evaluative aspect of meaning, two poems by William Blake
are called to the reader's attention:
Infant Joy"I have no name:I am but two days old,"
What shall I call thee?
"I happy am,
Joy is my name."
Sweet joy befall thee!
Pretty joy!
Sweet joy but two days old,
Sweet joy I call thee:Thou dost smile,
I sing the while,
Sweet joy befall thee!

11

Infant Sorrow
My mother groaned! My father wept;
Into the dangerous world I leapt;
Helpless, naked, piping loud,Like a fiend hid in a cloud,Struggling in my father's hands,
Striving against my swadling bands,
Bound and weary I thought best
To sulk upon my mother's breast.
In these two poems, expressing opposite qualities of affect, the frequencies of the criticalwords (i.e., words which convey the major
content, and hence not articles, pronouns, orauxiliary verbs) were averaged. The averagefrequency of Infant Joy is 2,037. The averagefor Infant Sorrow is 1,116. Two formally similar verses, one by Browning and the other by
Shelley, show the same pattern:Song. R. Browning
The year's at the spring,
And day's at the morn;
Morning's at seven;
The hillside's dew-pearled;
The lark's on the wing;
The snail's on the thorn;
God's in his Heaven—All's right with the world.
Dirge. P. B. Shelley
Rough wind, that meanest loudGrief too sad for song;
Wild wind, when sullen cloud
Knells all the night long;
Sad storm, whose tears are in vain,
Bare woods, whose branches strain,
Deep caves and dreary main—
Wail, for the world's wrong.
The average word frequency of Browning's
poem is 1,380. The poem by Shelley—whichcomes to a rather different and sadder conclusion—has an average frequency of 728.
Stimulus Frequency Attitude: Correlational
Evidence
We may now turn to the more general question of the effect of exposure on attitude, still
limiting ourselves to correlational studies.
Here, less evidence exists, and the evidence
which is available is often indirect. But the

12

ROBERT B. ZAJONC

results are quite similar to those just reviewed.
For instance, Alluisi and Adams (1962) founda correlation of .843 between the preference
subjects expressed for the appearance of letters and their frequency in the language.
Strassburger and Wertheimer (1959) had
subjects rate for "pleasantness" nonsense
syllables varying in association value. Higher
association values consistently received higher"pleasantness" ratings. Wilson and Becknell(1961) and Braun (1962) successfully replicated these results. Braun also found thateight-letter pseudo-words, varying in theirorder of approximation to English (Miller,
1951), show the same pattern. These twostudies differ from the similar ones by Johnson, Thomson, and Frincke, discussed earlier,in that subjects in the former ones were asked
to judge how pleasant were the stimuli themselves, or how much subjects liked them (Wilson & Becknell, 1961), while in the latter
whether they meant something close to "good"or close to "bad."In 1947 the National Opinion ResearchCenter conducted an extensive survey on the"prestige" of various occupations and professions. Nearly 100 occupational categories
were rated for "general standing." Twentyfour of these occupations are labeled by single
words, such as "physician," "scientist," "janitor," etc. The remainder is described lesseconomically: "owner-operator of a printing
shop," or "tenant farmer—one who owns livestock and machinery and manages the farm."Thus, one is able to determine the frequency
of usage for only a part of this list—the 24
single-word occupations. The correlation between rated occupational prestige of these 24
items and the log of frequency of usage is .55.
Similar to the ratings of occupational prestige are the social distance ratings of ethnic
and racial groups, first developed by Bogardus(1925) over 30 years ago. Recent replications
show that these social distance ratings enjoy
remarkable stability (Bogardus, 1959). The
correlation between the so-called "racial-distance quotients," which are numerical equivalents of these ratings, and the log frequency
of usage of these ethnic labels is .33.
In order to explore relationships of thissort further, I have selected 10 countries
whose names are found in the Thorndike-

Lorge L-count, and whose frequencies can bearranged in increasing order in approximately
constant log units. These countries were thengiven to high-school students with the instructions to rank-order them in terms of liking.
Table 5 shows the average rank each country
received and its frequency of usage according
to the L-count. There seems to be little question about the frequency-attitude relationship.
The same relationship is found with American
cities. Selected were 10 cities that (a) arelisted in the Thorndike-Lorge L-count, and(b) can be arranged in increasing order of
frequency in approximately constant log units.
University students were asked how muchthey would like to live in each of these 10
cities. Their task, specifically, was to rankorder these cities according to their preferences "as a place to live." The averageranks, together with frequency counts of these
10 cities, are shown in Table 5.
Other subjects, also high-school students
in the Midwest, were asked to rate on a 7point scale how much they liked various trees,
fruits, vegetables, and flowers. In each case 10
items were selected which were listed in theThorndike-Lorge count and which could beordered according to a constant log frequency
unit. Table 6 shows both the average ratings(0 = dislike; 6 = like) and the frequency
counts for the four types of items. The rankcorrelations between the frequency and average attitude are .89, .85, .84, .81, .85, and .89,
for countries, cities, trees, fruits, vegetables,and flowers, respectively.
TABLE 5
PREFERENCE RANKS AND FREQUENCY COUNTS
FOR 10 COUNTRIES AND 10 CITIES
CitiesCountries

Country

England
CanadaHolland
GreeceGermany
Argentina
Venezuela
Bulgaria
Honduras
Syria

AverFre- age prefquency erence
rank

497
130
59
31
224
15
9
3
1
4

2.67
3.33
3.42
4.00
4.92
6.08
6.58
7.75
7.92
8.34

City

BostonChicagoMilwaukee
San Diego
DaytonBaltimore
Omaha
Tampa
El Paso
Saginaw

AverFre- age prefquency erence
rank

255
621
124
9
14
68
28
5
1
2

2.75
3.08
3.83
4.25
5.75
6.08
7.08
7.08
7.50
7.58

THE ATTITUDINAL EFFECTS OF MERE EXPOSURE

13TABLE 6
PREFERENCE RATINGS or TREES, FRUITS, VEGETABLES, AND FLOWERS,
AND THEIR CORRESPONDING FREQUENCIES
Trees

f

APR

Fruitsf

APR

Vegetablesf

APR

Flowers

f

APR

pine
walnut

172
75
125
8
34
14
2
1
3
4

4.79
4.42
4.00
3.96
3.83
3.75
3.00
2.92
2.83
2.75

apple
cherrystrawberry
pear
grapefruit
cantaloupe
avocadopomegranate
gooseberry
mango

220
167
121
62
33
1.5
16
8
5
2

5.13
5.00
4.83
4.38
4.00
3.75
2.71
2.63
2.63
2.38

corn
potatolettucecarrotradishasparagus
cauliflower
broccolileekparsnip

227
384
142
96
43
5
27
18
3
8

4.17
4.13
4.00
3.57
3.13
2.33
1.96
1.96
1.96
1.92

rose
lily
violetgeraniumdaisy
hyacinthyucca
woodbineanemonecowslip

801
164
109
27
62
16
1
4
8
2

5.55
4.79
4.58
3.83
3.79
3.08
2.88
2.87
2.54
2.54

oak

rosewoodbirch

firsassafras
aloes

yew
acaciaNote.—f = frequency of usage; APR = average preference rating.

Of course, word counts do not faithfully
represent the frequencies with which one encounters the above items. And it is difficult
to discover precisely how often the average
Midwestern high school student encounters ayew, a cowslip, or a radish. But a fair index
of frequency of exposure can be found in farm
production data. For seven of the vegetables
in Table 6 farm production figures for 1963
are available, and they are shown below inthousands of tons:
corn (4.17)
potatoes (4.13)
lettuce (4.00)
carrots (3.57)
asparagus (2.33)
cauliflower (1.96)
broccoli (1.96)

2,340.9
13,777.1
1,937.6
843.8
187.8
123.4
123.9

Included also (in brackets) are average preference ratings of these seven vegetables. The
rank correlation between the production figures and the average preference ratings is .96.
Of course, this impressive correlation coefficient, like those we observed above, may
not reflect the effect of frequency on attitude
but the effect of attitude on frequency. Thus,
it can be argued that many roses are grownbecause people like roses. But it can also beargued that people like roses because there
are many roses growing. There is less ambiguity, however, with regard to the correlation between frequency of letters and thepreference for their appearance (Alluisi &Adams, 1962). There aren't so many e's inEnglish just because we like the way e's look.
Still, until there is experimental evidence, thequestion of which is the cause and which theeffect remains a matter of conjecture. We
shall now turn, therefore, to such experimental
evidence.
Exposure—Meaning: Experimental Evidence
Experiment I. The first experimental study on therelationship between exposure and word meaning
was carried out by Johnson, Thomson, and Frincke(1960). These authors first asked subjects to rate anumber of nonsense words on the good-bad scaleof the semantic differential. The subjects were theninstructed that "this is an experiment concerning
the effectiveness of repetition in learning to pronounce strange words correctly." Some of thesewords were shown once, others twice, 5 times, or 10
tunes. Subjects were required to look at these words
and to pronounce them on each presentation. Following this training procedure the words were again
rated on the good-bad scale. A significant exposure
effect was obtained, with the words shown frequently increasing on the evaluative scale. Strangely,
however, words which were seen only once in training were judged afterwards not quite as "good" as
before training. Thus, as a result of 2, 5, and 10
exposures words improved in meaning, and as aresult of but 1 exposure they deteriorated. Thisfinding, however, may be an artifact of the beforeafter procedure used by Johnson, Thomson, andFrincke. Moreover, frequencies and stimuli were
fully confounded in their study.
Our experiment used the same stimuli which, incidentally, came from the familiar experiment by
Solomon and Postman (19S2) on the effects of word
frequency on recognition threshold, but our design
differed from the one used by Johnson, Thomson,
and Frincke in several respects. In the JohnsonThomson-Frincke experiment the same words always
appeared in the same frequencies to all subjects.
Thus, the word "jandara," for instance, was given 10
times to each subject, and the word "mecburi" wasgiven once to each subject. It is possible that theeffects these authors obtained are not due to the

14

ROBERT B. ZAJONC

frequency manipulation alone, but that they dependon the stimulus material with which the frequency
variable was fully confounded. In our study words
and training frequencies were, therefore, counterbalanced in a Latin-square design. Because words
and the number of exposures were counterbalanced,
an after-only design could be employed, requiring
no premeasures. The effects of repeated exposure
could be observed for each word by comparing thefavorability rating it received after having been
exposed during training once, twice, five times, etc.
Eliminating premeasures also eliminated for eachstimulus one full exposure that necessarily preceded
and therefore accompanied the frequency manipulation.
The present experiment differs from that of Johnson, Thomson, and Frincke (1960) in several otherrespects which are less critical for the interpretationof results. The procedure of this experiment, therefore, is described in some detail. Except for somespecific changes, the same general methodology isfollowed throughout this series of studies.
Twelve seven-letter "Turkish" words, shown in
Figure 3, were counterbalanced against six frequencies (0, 1, 2, 5, 10, and 25) in six replications of theexperiment. Seventy-two subjects were run, one ata time, 12 subjects in each replication. The initial
instructions informed the subject that the experiment dealt with "pronouncing foreign words." He
was told that he would be shown some foreign words,
hear the experimenter pronounce them, and that hewould be required to pronounce them himself. The
words were typed on 3 X S-inch cards. On eachtrial a card was shown to the subject for approximately 2 seconds. Simultaneously the experimenter
pronounced the word, requiring the subject to follow him. Since each frequency class contained twoword-stimuli, there were 86 trials altogether. The
position of a given stimulus in the sequence of these86 trials was determined at random. Following theabove frequency training subjects were told thatthe words they had just learned to pronounce werein fact Turkish adjectives, and that their next task
would be to guess what they meant. The experimenter told the subject that he realized how nearly
impossible this task was, and he therefore did not
require him to guess the word meanings exactly.
Instead, it would suffice if the subject indicated on
a 7-point (0 to 6) good-bad scale whether each word
meant something good or something bad and towhat extent, because these Turkish adjectives all
meant something good or bad. These ratings weremade of the 10 stimuli which the subject received
during the frequency training, and of 2 additional
ones previously never seen by him.
The results of the experiment are shown in Figure
2 and in Figure 3. In Figure 2 are shown the ratings of "goodness" averaged for each of the six
frequencies, and plotted on a log scale. Each pointon that curve is based on 144 observations, and it
is clear that a strong exposure effect was obtained(F = 5.64; d/= 5/355; /><.001). Figure 3 showsthe exposure effect for each of the 12 words sepa-

rately. The ratings of "goodness" were averaged foreach word when it was given during training withthe lower frequencies of 0, 1, and 2 (hatched bars),
and when it was given with the higher frequencies
of S, 10, and 25 (solid bars). This was possible
because each word was used in each frequency
equally often but for different subjects. It is evident
from Figure 3 that some words are rated as having
more positive meaning than others, and this effect is
indeed significant (F = 8.35; # = 11/781; p<.001).
Apparently, some of these words "sound better" thanothers. But independently of word content, subjects
consistently rated the given word to mean something "better" if they had seen it (and had said it)
more often. This is true for all the 12 words used in
the experiment, a result that has a chance likelihood
equal to .00024.
Experiment II. Since the hypothesis proposed
above holds that it is mere exposure that is a sufficient condition of attitude change, the procedureused in Experiment I is not optimal for testing its
validity. Subjects in Experiment I were required topronounce the nonsense words during training, and
it is possible that a decrease in difficulty in pronouncing the words associated with successive presentations was responsible for the results. In other words,
subjects rated the frequent stimuli more favorably
because they found them easier to pronounce thanstimuli which they saw and pronounced only once or
twice. And, there were stimuli which they neverpronounced and, in fact, did not really know how
to pronounce. Wilson and Becknell (1961) suggested
that the evaluative ratings of nonsense syllables ofhigh association value are higher than of low associ-

CHINESE CHARACTERS NONSENSE WORDS

01]

2

5

FREQUENCY

FIG. 2. Average rated affective connotation of
nonsense words and Chinese-like characters as afunction of frequency of exposure.

THE ATTITUDINAL EFFECTS OF MERE EXPOSURE

IS

sufficient factor in affecting evaluative ratings but
not a necessary one. In order to eliminate the pronounciation factor and to reduce the subjects' active
LOW FREQUENCY
participation while exposure is being manipulated,
AFWORBU
the following experiment was carried out.
HIGH FREQUENCY
To meet the requirements of the definition of"mere exposure," Chinese characters were substituted
for the nonsense words. These stimuli were takenfrom Hull's (1920) concept formation study, and I
am told that not only are most of them meaningless, but that they are also far from the absolutely
NANSOMA
minimal standards of Chinese caligraphy. Nevertheless, they were quite adequate for our experimental
purposes. The subjects were again told that theexperiment dealt with the learning of a foreign
language, but now they were not required to proENANWAL.
nounce the characters. Nor were they able to pronounce them subvocally. They were simply instructed to pay close attention to the characterswhenever they were exposed to them. In all other
ZABULON
respects the experiment was identical to the one
employing nonsense words. Now, too, following
training subjects were told that the characters stood
LOKANTAfor adjectives, and that their task was to guess their
meaning on the good-bad scale. Characters and exposures were again counterbalanced. Figures 2 and 4
show the results, and it is obvious that the exposurefavorability relationship previously found with
nonsense words obtains (F = 4.72; dj = 5/335; p <.001) even if the individual's exposure to the stimu12345
lus consists of his passively looking at it for a
RATED "GOODNESS" OF MEANING
period of about 2 seconds. Figure 4 shows that the
FIG. 3. Average rated affective connotation of exposure effect is found for all stimuli but one.
The above results add strength to the hypothesis
nonsense words exposed with low and high frequenthat mere exposure is a sufficient condition for atticies.
tude enhancement. But again the last experiment did
ation value because they are easier to pronounce. In not succeed in completely eliminating a learning facorder to follow up their suggestion a group of 22 tor from the exposure manipulation, for it is possiUniversity of Michigan subjects were given the ble that this manipulation is now confounded withabove "Turkish adjectives" with the instructions to the ease of recognition. This danger of confounding,
rate them according to "how easy or difficult it is to however, is probably minimal because at no timepronounce" them. Using a 7-point scale, a signifi- were the subjects ever required to recognize orcant item-effect was revealed by an analysis of vari- discriminate the idiograms.
The results of Experiments I and II are in anance (F= 14.28; d f = 11/263; p<.00l), showingthat there are indeed differences among the nonsense apparent conflict with results reported by Amster
words in the ease with which they can be pro- and Glasman (1966). These researchers report a
nounced upon their first presentation. The Wilson- negative result using a procedure similar to that
Becknell conjecture is supported by a correlation of employed by Johnson, Thomson, and Frincke (1960).
.46 between the average ease of pronouncing the The experiment was similar in all respects except
words and the evaluative scores obtained in Experi- that meaningful English words were substituted forment I. These latter scores were obtained by the nonsense stimuli. No exposure effect was obaveraging for each word the rating it obtained in all served by Amster and Glasman for these meaningful
words. But this finding is not at all surprising. Nor
frequencies.
These results, however, in themselves do not is it especially significant for the understanding of
preclude a relationship between exposure and evalua- exposure effects. Adding one more occasion (or eventive rating. With ease of pronouncing held constant 10 more occasions) to see and say a perfectly wellthe exposure effect may still be obtained. This ex- known English word to all the times this word had
pectation is strengthened by the results of a study been seen and uttered by the individual in the past—
described above (Frincke & Johnson, 1960) in which a figure often in the thousands—really shouldn't have
homophone pairs differing in word-frequency were much effect on the meaning he attributes to it. The
rated for "pleasantness." Since homophones do not expectation of a change in the evaluative aspect ofdiffer in pronounciation, the obtained frequency meaning as a function of a few additional exposureseffects show that ease of pronouncing may be a becomes even less reasonable when we consider that

ROBERT B. ZAJONC

16LOW FREQUENCYHIGH FREQUENCY

I

2

3

4

S

RATED "GOODNESS" OF MEANING

FIG. 4. Average rated affective connotation ofChinese-like characters exposed with low and highfrequencies.
the change in affective connotation is a linear function of the logarithm of frequency, as we noted in
Figures 1 and 2. If n is the frequency of the subject's
preexperimental exposure to the word, then the comparisons made by Amster and Glasman involved thefollowing four frequencies: n + 1, n-\-2, n + S, andn + 10. Since n is large, perhaps as large as 1000, thedifferences in exposures amounted to fractions of1%.

Word-Frequency-Word-Value Relationshipas a Special Case oj the Exposure-Attitude
RelationshipIn the first section of this paper some evidence was presented suggesting that words
with positive affective connotations are used
more frequently (both in print and in speech)
than words with negative affective connotations. In the second section evidence wasgiven to suggest that the affective connotation of a word improves with their repeateduse. Because the second item of evidence rests
on experimental proof, in which the frequency of usage was systematically and independently manipulated, one cannot question
the causal direction implied in these data. But
finding that the frequency of usage affects
meaning needn't necessarily preclude the possibility that meaning determines the frequency
of usage. It is necessary, therefore, to examine
more closely the results on the correlational
evidence between word-frequency and wordvalue.
Why are positive words used more frequently? Besides the rather wistful and unlikely explanation that there are more positive than negative referents (i.e., we live in aparadise), one real possibility suggests itself.
The evidence reviewed so far deals only withusage per word. The totality of "good" and"bad" usage, however, depends on the numbers of different "good" and "bad" words inthe language. It is entirely possible, therefore,that the superiority of "good" words in frequency per word exists side by side with thesuperiority of "bad" words in their greater
variety. This possibility receives some support
from the fact that in English (and in a hostof other languages) prefixes and suffixes thatserve to negate or reverse meaning, such asanti, de, im, in, ir, less, un, etc., are mostcommonly attached to words having a positive connotation. Once attached to a word
they almost universally form a word with anegative affective connotation. Positive words
with these prefixes or suffixes are exceptional:
unselfish, independent, are some examples.
It would appear, therefore, that there areindeed more negative than positive words.
And if there are more different negative
words, the usage per word would naturally beattenuated for these words, because the total
usage would be distributed among a larger
universe of items.
Norman ° has asked a group of students toseparate a large sample of adjectives into
"good" ones and "bad" ones. On the average
2.31 more items were placed in the "bad" pilethan in the "good" pile. The frequency figures in Table 1 above show a pattern consistent with Norman's independent finding.
0

Warren T. Norman, personal
1965.

communication,

THE ATTITUDINAL EFFECTS OF MERE EXPOSURE
The average frequency of the preferred antonyms is 2.3 times larger than the average frequency of the nonpreferred antonyms! Therefore, for the material considered here, theratio of total positive and negative usage isequal to unity.
If repeated usage enhances the affective
meaning of words, a relatively large supply ofnegative words would in fact be needed. It
would be equally reasonable to expect that
there exist devices in language protecting
words from a deterioration of meaning. It is
entirely possible that the prefixes and suffixes discussed above serve this function. Because the negative qualities of these prefixes
and suffixes are independent of their referents,
because they are essentially abstract, and because they derive their negativity from thesemantic function they perform, words formedby means of these prefixes and suffixes areperhaps better able than root words to resist
an enhancement of affective connotation as aresult of repeated usage. I was unable to findevidence corroborating this point of view,
although there is a good deal of philologicalliterature on both positive changes in meaning(see for instance vanDongen, 1933) and negative changes in meaning (see, for instance,
Schreuder, 1929). Most of the sources, however, consider changes in meaning of rootwords only.
If there are many remaining doubts thatfrequency of words is a function of the valueof their referents, then the following frequencies of a few well-chosen but significant words
should once and for all dispel them:
Psychologist
ChemistEconomist
Sociologist
Astronomer
Geologist
Physicist
Geographer
Botanist
Biologist

36
32
32
14
12
9
8
7
6
S

Exposure-Attitude Relationship: Experimental
Evidence
Experiment HI. In all the experiments above thequestion asked of the subjects in rating the stimuli

17

following exposure dealt with the evaluative aspectof their meaning. The subjects were never required
to say just how much they "liked" the nonsensewords or "Chinese" characters. In all probability, theresults would have been the same if they were asked
directly to state their attitude toward these words
and characters, and the Wilson-Becknell (1961)
results support this conjecture. But because theirstimuli were essentially verbal, subjects' answers
could in these studies be strongly influenced by semantic factors. This would have been less likely, ofcourse, in the case of Chinese characters than in thecase of nonsense words.
As was pointed out above, there is some direct
evidence on the attitudinal effects of mere exposure,dealing almost exclusively with music appreciation.
Meyer (1Q03), for example, played to his studentsoriental music 12 to IS times in succession. In mostcases the students' introspective protocols indicateda better liking for the pieces on the last than on
the first presentation. One of the students who took
part in Meyers' experiment (H. T. Moore), andwho showed enhancement effects of repeated exposure ("I liked the last time better than the first,
because I became more used to the successive
chords"), followed up this work in a study of his
own 20 years later. Moore and Gilliland (1924)
played to their students jazz and classical records
once a week for 25 weeks. Liking for classical records increased, but no change was found for jazzmusic. Similar results are reported by other writers(Krugman, 1943; Verveer, Barry, & Bousfield, 1933;
Washburn, Child, & Abel, 1927). Downey andKnapp (1927) played to 33 students a variety ofmusical selections (e.g., Tschaikowsky's Marche
Slave, Massenet's Meditation from "Thais," Columbia, The Gem of the Ocean, etc.) once a week forfive weeks. All pieces of music except one (Columbia, The Gem of the Ocean) became better liked at
the close of the sessions. Alpert (1953) presented
subjects with sounds having unfamiliar rhythms. His
subjects found these sounds at first unpleasant.
After repeated presentations, however, the liking forthem increased. Additional exposures of subjects tothe tones resulted in increasing indifference on thepart of the listeners. More recently, Mull (1957)
found that upon repeated exposure to their music
subjects enjoyed Schoenberg and Hindemith more.
In the area of visual arts, Pepper (1919) foundthat repeated exposure resulted in more positive
esthetic judgments of unusual color combinations.
Krugman and Hartley (1960), however, using
famous paintings, could only find ambiguous results. Maslow (1937) projected for 4 days in succession 15 paintings of great masters. Six days following the last presentation the 15 paintings were
presented once again, and interspersed among themwere 15 others (matched for the artist) which thesubjects had never seen. The results indicated agreater liking for the familiar paintings. Maslow(1937) also made tests of preference, frequently
with similar results, for other familiar and unfamiliar objects, such as rubber bands, paper clips,

18

ROBERT B. ZAJONC

blotters, pens, pencils, etc. A similar experiment to
the one with paintings, but using instead Russian
girls' names, showed the same results. The same
subjects were used in all these studies and the sessions took place in the same room, the subjects always sitting in the same chairs. Toward the end of
the testing program Maslow asked if anyone would
like to change seats. No one did, preferring, apparently, to remain in the familiar one.
Although the results of the above studies are
fairly consistent, the conditions under which they
were carried out make their conclusions somewhat
less than compelling. In the majority of instances,the circumstances of the repeated exposure werequite ambiguous. The experiments were usuallyconducted in classes, the instructor serving as theexperimenter. Subjects often responded aloud, thus
being able to influence each other's judgments andopinions. Prior to the sessions the experimenter
often expressed his own preferences. The stimuli,
repeatedly shown, were not always exposed under
the same conditions, and the material, exposures, andsequences were seldom counterbalanced. But in allof these experiments a pattern of results emerges
showing that the frequency manipulation has more
pronounced attitude effects for stimuli that are novel,
unfamiliar, or unusual than for familiar stimuli.
This pattern is, of course, consistent with the observation that attitude enhancement is a function of
the logarithm of frequency.
Becknell, Wilson, and Baird (1963) have recently
reported more convincing support for the exposureattitude hypothesis. Slides of nonsense syllables were
presented with different frequencies (1, 4, 7, and 10).
Following this exposure training (which also included
interspersed presentations of slides with landscapes
and with ads) female subjects were given pairs ofboxes containing nylon stockings, and they wereasked to choose the "brand" they preferred. These"brands" corresponded to the nonsense syllables previously shown, and they were printed on the boxes.
Each subject received two different pairs of boxes
for comparison. The paired-comparison data showeda tendency of subjects to prefer the box marked by
the more frequent syllable. Again, however, thesemantic component is not excluded from the effects
obtained in these two studies.
There is one more item of evidence, somewhat
indirect, on the problem of the effects of exposure.
In a study by Munsinger (1964) subjects were given
the opportunity to present to themselves CVC trigrams whose association value, evaluation scalevalue, and prepotency score (Handler, 19SS) werepreviously assessed. By pressing a response key the
subject would expose in a small window a trigram
which he would then have to spell. The rate at
which he key-pressed constituted the dependentmeasure. In one of Munsinger's experimental groups
subjects could expose to themselves, by means ofthat key response, trigrams that were matched for
association and prepotency. All these trigrams, however, previously scored low on the evaluative scalesof the semantic differential. After subjects reached

t 3.5

J3.0

2.5 -

I

2

5

10

25

FREQUENCY

FIG. 5, Average attitude toward photographs as afunction of frequency of exposure.
an asymptotic key-pressing rate, the experimental
conditions changed such that now the subjects' response would expose trigrams that were high inevaluation, although they were still matched for
association and prepotency. A significant increase in
key-pressing rates is reported by Munsinger following the change in the affective value of the trigrams.
Again, however, the semantic component is not entirely excluded from the effects obtained in these
two studies.
Because they are less a matter of semantic factors,
we have chosen to manipulate interpersonal attitudes
by means of exposure. Using the same experimental
design as with the Chinese characters, faces of men(photographs of graduating Michigan State University seniors taken from the MSU Yearbook)were employed as attitude objects. The experiment
was introduced to subjects—all students at the
University of Michigan—as dealing with the problem of "visual memory." Following the exposuremanipulation, which consisted of presenting eachphotograph a different number of times for a periodof 2 seconds, subjects were asked to rate on a 7-point
scale how much, they might like the man on eachphotograph. The results of this study are shown in
Figures S and 6. While the exposure effect is not asclear as previously (only 9 of the 12 stimuli showit), it is still rather impressive (F = 9.96; dl = 5/355; p< .001).

The Exposure-attitude Hypothesis andRelated Theoretical Issues
The above results raise a series of empirical and theoretical questions. Are all attitudes

THE ATTITUDINAL EFFECTS OF MERE EXPOSURE

*-~

&*»

*% & $

Vfti x19i •* 4*

arfL

?^

\SfA^

FIG. 6. Average attitude toward photographs exposed with low and high frequencies.

enhanced by mere repeated exposure? Is
there a number of repetitions beyond which
attitude begins to become negative? Does thisnumber vary systematically across attitude
objects? Are these effects stable? These andsimilar questions can only be answered byfurther empirical work. On a theoretical level
these questions address themselves primarily
to those psychological processes that mediate
exposure effects.
Let us first consider a possible biologicalsignificance of an exposure-enhancement
mechanism. A stimulus presented for the firsttime evokes in the organism an instinctive
fear reaction. Lorenz (1956) noted that ayoung raven,confronted with a new object, which may be acamera, an old bottle, a stuffed polecat, or anything else, first reacts with escape responses. He will
fly up to an elevated perch, and, from this point of
vantage, stare at the object literally for hours. After
this he will begin to approach the object very
gradually . . .

Biihler, Hetzer, and Mabel (1928) observedthat human infants reacted to a strange soundby crying out with fear. Upon the second exposure of the sound stimulus, movement andvocalization that indicated displeasure wereobserved. On the third exposure, the infants
listened to the sound showing some signs ofattention, but did not seem to show any displeasure. On the fourth exposure, they lookedin the direction of the sound with detectableinterest. These facts, of course, are borne out
by common observation. Hunt (1965) reported that young infants he observed preferred a familiar mobile to a new one. And
the "Black Bag" story cited in the introduction represents another example of phenomenain this category. At the outset the "Black
Bag," in fact, attracted a good deal of hostility. Cairns (1966) has recently presented avery convincing argument that the affiliative
behavior and social attachments among animals are solely determined by the animals'
exposure to one another. Examining evidence
on affiliative preferences of animals observed
under conditions of inter- and intraspecific cohabitation and of animals deprived of social
contact, Cairns concluded that such affiliative
preferences vary directly with the length of
the association and with the importance ofthe cues which are generated in the course of
the association. Cairns, moreover, did not
limit his conclusion to inter-animal social attachments but prposed that "animals tend toremain in the presence of [any] objects towhich they have been continually exposed[p. 409]."
The survival value of an avoidance reflex
to a novel stimulus is obvious. But there isno direct evidence that all organisms areequipped with an avoidance reaction occurring
upon the encounter of a novel stimulus. However, if we assume that they are, then the
exposure-attitude hypothesis becomes more

ROBERT B. ZAJONC

20

reasonable. The first encounter with the novel
stimulus produces fear reaction. If no negative consequences are associated with thisfirst encounter, the avoidance reaction upon
the second encounter will naturally be weaker.
If such encounters continue, and if no otherevents—negative in their consequences forthe organism—accompany these encounters,then the organism's attitude toward thestimulus must improve. To be sure, the hypothesis does not deny or preclude the effects
of reinforcement. The exposure of a stimulus
coupled with reward will strengthen the animal's approach behavior; and the exposureof stimulus coupled with a noxious event will
strengthen his avoidance reactions. But inthe absence of reward or punishment, mere
exposure will result in the enhancement of
the organism's attitude toward the given
stimulus object.
If novel stimuli evoke fear, conflict, or uncertainty, one should be able to detect thesestates, and to observe their dissipation upon
repeated exposure. To the extent that GSR
measures arousal that is associated with theabove states, we would expect greater GSRs
upon the presentation of novel stimuli thanupon the presentation of familiar ones, andwe would also expect a drop in GSR reactivity to be the consequence of repeated stimulus exposure.
Experiment IV. Changes in affective arousal that
occur as a result of repeated exposure of a novel.35

stimulus were examined in an independent experiment. Fifteen subjects were presented with nonsensewords (the same as in Experiment I) in a series of
86 trials. Two words appeared 25 times, two 10 times,
two 5 times, two twice, and two once. The positionof a word in the series of trials was determined bya random device. Words were counterbalanced
against frequencies in three experimental replications. Due to a mechanical failure of the apparatus,
data for one subject could not be used, and were
not included in the analysis.
On a given trial, the stimulus word was projected
onto a screen for a period of 2 seconds, and thesubject's GSR was recorded. The interstimulus interval was 20 seconds. GSR was measured only
during the first 10 seconds following stimulus onset,
and all GSRs occurring during the last 12 secondsof the interstimulus interval were treated as artifacts. The Kaplan-Hobart technique of GSR measurement (Kaplan & Hobart, 1964), which requires
current of only 10 microamperes, was employed.
Zinc-zinc sulphate electrodes (Kaplan & Fisher, 1964;
Lykken, 1959) were applied to the forefinger andthe middle finger of the subject's nonpreferred hand.
The results of the experiment are shown in Figure
7 and Figure 8. In Figure 7 changes in conductanceare plotted for each successive presentation of thestimulus-word. For purposes of clarity data for only
one stimulus are graphed in each frequency class.
The results for the other set of stimuli are thesame. It can be seen that, in general, successive
presentations result in a lower autonomic reactivity. After about seven or eight exposures a stable
asymptote is reached. Hence, only stimuli shown 25
and 10 times attain an asymptote. Words shown
five times, twice, or once generate greater changes
in conductance even on their last exposure. Thiseffect is seen better in Figure 8 in which GSRs on
the last exposure of the stimuli were plotted. As
prior frequency of exposure increases there is a—• 25 Exposures. .o 10 Exposures—» 5 Exposures—..7 Z Exposures
I Exposures

30

°.25
20
.15
.10

5.05
Llj

5

5

10

15

20

25

30

35

40

45

50

55

60

65

70

75

FIG. 7. GSR obtained upon repeated exposures of nonsense words.

80

85

THE ATTITUDINAL EFFECTS OF MERE EXPOSURE
40

1

2
5
10
FREQUENCY OF PAST EXPOSURE (LOG SCALE)

2 5

FIG. 8. GSR obtained on the last exposure of nonsense words exposed with various frequencies.
lesser change in conductance upon stimulus presentation. This effect is significant at the .OS level (F =4.01; df = 4/117).
These results cannot be due to an overall adaptation that may be occurring as the series of the 86
trials progresses. It is clear that the stimulus shown
just once generated a substantial GSR although it
occurred as late as on the 67th trial. As a matter offact, its GSR does not differ from the GSR obtained
for the first presentation of the other stimuli. The
last presentation of the stimulus word that had justone prior exposure also resulted in a substantial
GSR although it occurred on the 64th trial. And on
the whole, although there is variability over trials, at
any one point during the series GSR's are higher for
stimuli with infrequent prior exposures than for
stimuli previously seen by the subject many times.
It seems, therefore, that with increased exposure
there is a genuine reduction in stimulus-evokedarousal. These findings are in agreement with thosereported by Berlyne, Craw, Salapatek, and Lewis(1963). In their study subjects were shown visual
patterns differing in complexity and in incongruity.
The patterns were presented for 3 seconds on threesuccessive occasions. A significant drop in GSR was
obtained between the first and the second presentation. But no significant GSR effects were associatedwith complexity or incongruity.

DISCUSSION
While the bulk of the results presented andreviewed in this monograph supports the
hypothesis that repeated exposure is a sufficient condition of attitude enhancement, there
are findings and theoretical formulations which

21

appear to be in conflict with the hypothesis.
The most pronounced source of ostensibly
contradictory results is in the area of exploration and curiosity. There is impressive
evidence today that in a free situation thesubject (human or animal) will turn toward
a novel stimulus in preference to a familiar
one (e.g., Berlyne, 1960). If such orienting
and exploratory "approach" behavior is a
symptom of a favorable attitude toward thestimulus object, the wealth of data on exploration and orienting behavior (Berlyne,
1950, 19SS; Berlyne & Slater, 1957; Dember&Milbrook, 1956; Montgomery, 1953; Thiessen & McGaugh, 1958; Thomson & Solomon,1954) stands in clear contradiction to thosereported in this monograph.
But there is at present no direct evidence
to support the above assumption. And, on thecontrary, it is more likely that orienting toward a novel stimulus in preference to a
familiar one may indicate that it is less liked
rather than it is better liked. Ordinarily,
when confronted with a novel stimulus theanimal's orienting response enables it to discover if the novel stimulus constitutes asource of danger. It need not explore familiar
stimuli in this respect. Novelty is thus commonly associated with uncertainty and withconflict—states that are more likely to produce negative than positive affect. Most recent
work by Harrison (1967) indicates quite
clearly that exploration and favorable attitudes are in fact negatively related. Using
nonsense words, Chinese characters, andphotographs of men's faces, Harrison obtained measures of liking from one group of
subjects and measures of exploration from another group. The correlations between exploration and liking were —.69, —.69, and— .60 for nonsense words, characters, andphotographs, respectively. If the function oforienting behavior is eventually to change thenovel stimulus into a familiar one, it is also its
consequence to render the stimulus object
eventually more attractive (or perhaps merely
less repulsive).
In his research Harrison also obtained dataon the behavioral consequences of exposure,and in particular, on response conflict thatnovelty seems to arouse. It is a truism, of22

ROBERT B. ZAJONC

course, to assert that novel stimulus is one towhich no specific response, beside orienting,has as yet been attached. But the novel stimulus cannot fail being similar to an entire hostof other stimuli that the individual had encountered in the past, and to which he had
attached specific responses. And it is entirely
likely that some of these generalized response
tendencies that the novel stimulus simultaneously excites are mutually incompatible;that is, they cannot all be emitted at the sametime. This antecedent condition is what makes
response conflict (of some, however small,magnitude) a necessary concomitant of novelty.
Using latency of free associations as ameasure of response conflict, Harrison wasable to demonstrate that response conflict ismarkedly reduced upon repeated exposure of
a novel stimulus. Chinese ideographs wereshown to a group of subjects once, twice, S
times, 10 times, and 25 times, in a manner
similar to that used in other experiments described above. Following this exposure manipulation, Harrison presented each stimulus
once again requiring the subject to respond"with the first thing that came to mind." Included now were also Chinese ideographs thatthe subject had never seen. The latency ofthese free associations was obtained on eachsuch trial, and the results revealed a systematic and significant drop in latencies as afunction of the frequency of prior exposure.
Another set of data which may also be ofsome consequence for the exposure-attitude
hypothesis is to be found in the area of semantic satiation. In a typical semantic-satiation experiment the subject is asked to repeat words, two or three per second, for aperiod of IS seconds. The general findings inthis area indicate that following this sort of
rapid repetition the word seems to "lose" itsmeaning (for a review of the literature see
Amster, 1964). Loss of meaning is measured
by a departure from polarity on semantic
differential scales, such as good-bad, strongweak, etc. (Lambert & Jakobovits, 1960).
When repeated in rapid succession and rated
on some semantic differential scale, immediately thereafter the words tend to be placedneither toward one (e.g., good) nor the other(e.g., bad) end of the scale, but are rated
toward the neutral point of the scale. While
several studies have demonstrated a reduction of polarization following rapid repetitionof a word (Das, 1964; Kanungo & Lambert,
1963a, 1963b; Messer, Jakobovitz, Kanungo,& Lambert, 1964), there is an equal amountof conflicting evidence (Amster & Glasman,
1965; Floyd, 1962; Reynierse & Barch, 1963;
Schulz, Weaver, & Radtke, 1965). Yelen and
Schulz (1963) attribute satiation findings toa regression artifact. A reduction of polarityof positive words as a result of repetition
would indeed be embarrassing for the exposure-attitude hypothesis. A reduction of polarity of negative words (i.e., words with asemantic score below the neutral point)
would, of course, be entirely in agreement withthe present results, for they would simply beshowing an enhancement effect along theevaluative dimension. It should be noted that
all our stimuli initially received negative ratings, that is, below the neutral point, 3, on
the 0-6 good-bad scale. Given no exposure atall, the evaluative ratings for the Turkish
nonsense words, Chinese-like characters, andphotographs were 2.56, 2.67, and 2.79, respectively. In terms of polarity these averages
are —.44, —.33, and —.21. Contrary to thesemantic satiation hypothesis, absolute polarities increased after 25 exposures, for they
were +.61, +.78, and +.61, respectively.
Admittedly, the controversy within semantic
satiation literature may have to be resolved
before clear implications for the exposure
effect can be drawn. Parenthetically it should
be noted, however, that the form of exposure
used in the semantic satiation paradigm (i.e.,
30 to 45 repetitions in 15 seconds) is not what
has been above defined as the sufficient condition of attitude enhancement. Moreover, insemantic satiation studies the stimulus is commonly a verbal response made by the subject
himself. Whether such a response-produced
stimulus should constitute what is meant by
mere exposure is a matter of some doubt.
The above hypothesis and data seem to beconsistent with the theory of reinforcement
recently proposed by Premack (1959). This
new and engaging approach to reinforcement
effects, for which a good deal of impressiveTHE ATTITUDINAL EFFECTS OF MERE EXPOSURE
evidence has already been accumulated (Premack, 1961, 1962, 1963, 1965; Premack &Bahwell, 1959; Premack & Collier, 1962),
holds that if the emission of one response, A,
is made contingent upon the emission ofanother response, B, and if A occurs withgreater frequency than B, B will gain in therate of emission. A can, therefore, be considered as having positive reinforcement value
which seems to depend alone upon its frequency of occurrence. Contingencies between
responses can be introduced by controlling
manipulanda or the availability of goal objects. Thus, for instance, in studying theseeffects in Cebus monkeys, Premack (1963)
used four manipulanda: a plunger, a hinged
door, a vertically operated lever, and a horizontally operated lever. It was possible to
make any manipulandum inoperable at any
time, and to make it operable only in the caseof a prior manipulation of another manipulandum. Thus, each manipulandum could
serve for the reinforcwg or for the reinforced
response. After establishing for each monkey
the probabilities of operating each item underfree access to all, contingencies were arranged
between pairs of items, such that, for instance, the vertical lever could not be operated unless the animal pulled the plunger,
or the hinged door remained locked unlessthe subject pressed the horizontal lever, etc.
The introduction of these contingencies resulted in the predicted effects. In general,
responses that were less probable increased in
the rate of emission when more probableresponses were made contingent upon them.
When two responses were equal in probabilityof emission little or no change in response
rates was observed.
Viewed in the present context, the individual's response probabilities can be taken
as an indication of his "attitudinal liking"or "attraction" to the goal objects of these
responses, or to the instrumental stimuli associated with them. To the extent that the
reward value of a given response, A, which iscontingent upon another response, B, is adirect function of A's probability of emission,then increasing its probability of emission will
increase its reward value. Premack (1961)
was able to demonstrate such an effect in rats

23

for licking and bar pressing. Changing thelanguage somewhat, it may be said that theindividual's "attitudinal liking" for the goal
object of the response A increases with theindividual's exposure to the goal object of A.
In Premack's work continuous reinforcement
schedules are used and, hence, the individual'sfrequency of exposure to the goal object of A
is equal to the frequency of emission of A.
There are important differences between
the phenomena observed by Premack andthose reported in the present paper. In mostof his experiments the frequency of occurrenceof responses results from an independent, perhaps genetically given or previously acquired,response preference of the subject. In the experimental work on attitudinal effects of exposure, the frequency of occurrence of thestimulus-object is deliberately manipulated.
Moreover, the subject usually does not havea prior preference for the stimulus exposed.
On the contrary, he may often manifest
avoidance tendencies. But the parallel is compelling.
While there is a great deal in common between Premack's work on reinforcement andthe research on attitudinal effects of exposure,a clear understanding of the implications of
one for the other requires a systematic determination of what "reinforcement value"and "attitudes" have in common that makes
them both equally vulnerable to simple frequency effects.
CONCLUSION
The balance of the experimental results reviewed and reported in this paper is in favorof the hypothesis that mere repeated exposureof an individual to a stimulus object enhances his attitude toward it. But, as yet,the account books cannot be closed. Further
research must examine the boundary conditions of the exposure-attitude relationship, for
it is possible that the neat linear log-frequency-attitude relationship, repeatedly observed here, may well break down under someconditions. This future research must, in particular, concentrate on the effects of large
frequencies of exposure, on duration of exposure, on interexposure intervals, and on

24

ROBERT B. ZAJONC

many other similar parameters of mere exposure. This research must also assess theapplicability of the exposure-attitude relationship to a greater variety of stimulus objects. The question of generalization of specific exposure effects is of equal theoreticalimportance. Does repeated exposure to agiven stimulus result in the enhancement of
attitudes toward similar or related stimuli?
Because the above effects seem to be a function of the logarithm of frequency of exposure, they are more apparent and more pronounced for differences among small frequencies than for differences among large frequencies. For the same reason, attitudinal enhancement produced by means of exposure
will be more readily effected for novel objects
than for familiar ones. It is likely that exposure effects for very familiar objects areabsent completely or are so small that theycannot be detected at all by methods now
available. As we have seen above, Amster andGlasman (1966) failed to obtain the exposure
effect for common English words. It will be
important for future research, therefore, todetermine the range of familiarity for which
the exposure effect is obtained.
Mere exposure is a necessary preconditionof a vast variety of experimental manipulations. For example, in attempts to change
attitudes by means of persuasive communications the attitude object is mentioned repeatedly, regardless of whether the attempt is directed toward making the attitude more favorable or toward making it less favorable. Making attitudes more favorable should, therefore, be easier than making them less favorable. It is interesting that studies on theeffectiveness of persuasion in attitude change
seldom try to effect a negative change, andalmost never compare the relative success ofa pro-persuasion with the success of a conpersuasion. In an attitude-change study Tannenbaum and Gengel (1966) have recently
obtained only positive shifts, although botha positive as well as a negative manipulation
were employed.
The partial reinforcement manipulation,
too, is subject to possible confounding with
the number of stimulus presentations. Erlebacher and Archer (1961), for instance, reported the curious result that at the comple-

tion of training greater numbers of correct
responses were associated with smaller percentages of reinforcement. However, in thevarious conditions of reinforcement subjects
worked until they performed in succession apredetermined number of correct responses,
the same for all percentages of reinforcement.
Therefore, percentage of reinforcement was inthis study completely confounded with thenumber of stimulus exposures (and also with
the number of reinforcements). Althoughmany authors have tried to cope with thisconfounding in one way or another (e.g.,
Festinger, 1961; Kanfer, 1954; O'Connell,
196S), the methodological difficulties have notbeen completely overcome. None of the four
variables that are associated with the partial
reinforcement effect-—percentage of reinforced
trials, number of trials, number of positive
reinforcements, number of nonreinforcements—can be studied independently of the others.
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