280

and 1.00 by definition. Table 1 gives the com-
posite speed test results in these terms.

The 22 individuals with congenital or rheu-
matic heart-defects were slower than the healthy
individuals, but not significantly so.

Both groups of Ss with non-hypertensive car-
diovascular diseases (Groups IIIa and IIIb)
were very significantly slower than the healthy
group and very similar to each other.

The hypertensive Ss showed a more compli-
cated picture: Group IVa, Ss who were not
medicated and presumably susceptible to situa-
tional stress, were at least as slow as the arte-
riosclerotic Groups IIIa and IIIb. In contrast,
the hypertensive volunteers, who were medi-
cated and presumably less liable to possible
situational stress, performed as well as the
healthy group. ;

The nine cerebrovascular Ss performed most
slowly of all, as would be expected. It is inter-
esting that the unmedicated hypertensive Ss
(Group IVa) were almost as slow as these cere-
brovascular cases.

All subgroups listed in Table 1 were faster
than would be exected on the WAIS Digit Sym-
bol Test. The WAIS Manual gives conversion
scales for various adult ages, so that the per-
formance of each age group in the large stand-
ardization samples has a mean of 10.0 and a

Table 1. Age-adjusted Composite Speed-test Scores

for All Subjects Aged 35-59.
Group No oMn o¢ P
(Gtd.
Score)
Ta, Healthy volunteers 3390.00 1.00
Tb. “False positives,” maximally
stressed healthy cases 16 0.08 0.98 >0.50
I, Rheumatic or congenital defects,
compensated, AHA class TA 2 0.38 1.07 >0.10

Illa, Arteriosclerotic cardiovascular

dizease, AHA class TA or IB

(iuild or moderate, compensated),

not medicated, some situational

stress 47
IIlb, -Arteriosclerotic cardiovascular

disease, AHA class IA or IB, not

‘medicated, volunteers not under

situational stress 13
Vo, Essential hypertension, AHA class

TA oF IB, not medicated, some

situational stress ug
IVb. Essential hypertension, AHA class

TA or IB, medicated, volunteers

‘not under situational stress 13
YV. Individuals displaying history or

physical evidence of cerebro-

‘vageular disease, recovered and

without overt mental /behavioral

deficits 8

<0.001

1.54 1.53 <0.01

1.74 1.40 <0.001

0.77 >0.10

1,24. <0,01

SPIETH

standard deviation of 3.0. In these terms, our
healthy Ss aged 35-59 had mean Digit Symbol
scores of 13.2, or slightly more than one stand-
ard deviation above the population mean score;
cardiovascular Groups IIIa, IIIb, and [Va con-
sidered together had a mean score of 11.1 points.
The estimated standard deviations of the scores
of various groups of Ss with pathological condi-
tions were no greater than the population stand-
ardard deviation of 3.0, while the standard de- .
viation. for the healthy individuals was con-
siderably less: about 1.8 points instead of 3.0.
Because a previous study (Birren & Spieth,
1962) showed correlations of about 0.40-0.65
between the Digit Symbol Test and the other,
very brief, speed tests in the battery, it seems
safe to conclude that our aviation sub-popula-
tion is superior to the population at large on
speed tests in general.

The relative discriminative powers of the
various speed tests were assessed by t-tests be-
tween mean scores on individual tests of the
healthy group versus Groups IIIa, IIIb, and
IVa combined, the healthy group versus the
cerebrovascular group (both sets of tests used
age-adjusted scores), and young healthy Ss
(ages 23-39) versus old healthy Ss (age 50-
59). The Psychomet Stimulus-matching Tests

Table 2. Average Length of the Speed Tests and
t-values of Mean Differences in Reaction Times

‘Between Various Subgroups.
Ay. Time Healthy Healthy
for vs. Gps. vs. Young
Healthy (a+ Cerebro- (age 23-39)
Aged T1Ib+ vascular ws, Old
4044 IVa) Ss (age 50-59)
‘Tests or Combinations Ge) © 0) ©
I, Paychomet Tests
1. Simple light matching,
sum of 4 runs of 10
responses 28 64> 1.85 8.208
2, Small digit or letter
matching, buttons
labeled in order 45 Boab 4.7 8.1
8, Small digit or letter
matching, buttons
labeled in random
sequence 6 7.AT® 5.66% 10,78
4. Large digits or letters,
battons labeled in
serambled sequence 85 6.24 5.87 «8.460
5. Color-plus-symbol
stimulus matehing 45 5.77 2.688 7.89%
6. Tri-color stimulus
matching 90 3.5 2.25 1.94
TI, WAIS Digit-Symbol Test 90 4.84 3.31% 6.335
Mil, Trail Making Tests A+B 86 47 8,16" 3,70

‘Statistically significant at less than 0.01 level of confidence.
Statistically significant at less than 0.001 level of confidence.



HEALTH STATUS AND PSYCHOLOGICAL PERFORMANCE

No simple conclusion can be drawn from this
study about the effects of hypertension on per-
formance. The untreated hypertensive Ss in
Group IVa had reason to be under considerable
situational emotional stress and performed quite
poorly; the essentially hypertensive members of
Group IVb, whose blood pressures were being
kept within normal limits by drug treatments,
and who also were tested under presumably
more relaxed circumstances, performed as well
as the healthy control group. It is plausible
(Spieth, 1964) that both emotional stress and
blood pressure were causal variables in this
study.

Does the slowness of the cardiovascular S’s
performance reflect a “basic” or “fundamental”
reduction in mental efficiency, or merely a more
cautious self-pacing? I think the former is true,
for these reasons: a) Most of the cardiovascular
Ss in this study hoped to demonstrate them-
selves as fit to fly or control air traffic. b) The
cardiovascular disease Groups IIa, IIb, and
IVa were somewhat poorer than like-aged
healthy Ss on the untimed recall parts of the
Halstead Tactual Performance Test—signifi-
cantly so at recalling the shapes of the blocks.
This recall test was truly free of speed effects,
because each $ was given whatever time was
necessary to reach the performance criterion be-
fore the untimed recall test began. c) In the
Psychomet Test battery, there was a clear-cut,
health-group by subtest-complexity, interaction
of reaction times. All Psychomet Subtests were
performed on the same stimulus and response-
button panel. The stimulus-oculomotor and
the arm-motor activity were the same in all sub-
tests, while the complexity of the information-
processing varied considerably. If simple “mo-
tor” slowing were all that were involved, we
would expect the ratio of reaction times of
healthy to cardiovascular Ss to decrease from
the less to the more time-consuming tasks,
while in fact the reverse occurred, as may be
seen in Figure 2. The mean RT of the cardio-
vascular Ss on the simplest Psychomet test was
about 0.05 second longer than the mean RT of
healthy Ss, while on the more complex tests the
cardiovascular Ss took several tenths of a second
longer per reaction than did the healthy Ss.
Thus most, and possibly all, of the slowness of
the cardiovascular Ss on the more complex sub-
tests came not in the “doing,” but in the “de-
ciding what to do” phase of the reaction pro-
cess. This fact does not refute the “self-pacing”
hypothesis of cardiovascular Ss’ slowness, but it

283

does, I believe, weaken the case for it some-
what. d) Outside evidence counter-indicates a
“self-pacing” hypothesis: A set toward slowness
would not seem to explain the findings by
Simonson and Enzer (1941) of subnormal
flicker fusion thresholds in Ss with hypertension
and/or coronary heart disease, nor Reitan’s
(1954) finding of significantly more numer-
ous “organic signs” in hypertensive Ss than
in controls on the untimed Rorschach test.
The most interesting indirect information comes
from Anderson’s (1963) finding that coronary
heart disease Ss, while they performed more
slowly than control Ss on a speeded test, also
made more errors: one would expect fewer
errors from a set or attitude toward limiting
one’s pace.

The data in this study further confirm several
other studies which indicate that middle-aged
individuals with coronary heart disease or hy-
pertension perform more poorly than control Ss
on a variety of psychological tests and tasks,
probably even when there is no independent
evidence of cerebrovascular impairment. In
addition to the aforementioned studies, Enzer,
Simonson, and Blankstein (1942) reported that
Ss with coronary heart disease and/or hyper-
tension had a lower maximum finger-tapping
rate than healthy Ss of like age; this reaction
they ascribed to circulatory insufficiency. Apter,
Halstead, and Heimburger (1951) found that
essential hypertensive Ss showed significantly
higher indices of organic brain impairment than
controls, when the highly valid Halstead Im-
pairment Index battery was used. Birren, But-
ler, Greenhouse, Sokoloff and Yarrow (1963)
reported that elderly hypertensive Ss showed
slower serial choice reaction times than health-
ier old Ss. Reitan and Shipley (1963) reported
a relationship between cholesterol level and
performance deficits in old men but not in
young men on a battery of tests known to be
a sensitive index of brain impairment.

The importance of the present study, if any,
is that performance deficits were found in
Ss who were fully recovered from an acute ill-
ness, who presented no history or independent
symptoms of cerebrovascular disorder, and
whose cardiovascular disease symptoms were
rated by cardiologists as “mild” or “moderate”
(Classes IA or IB by American Heart Associa-
tion Standards).

The results of this study do not prove that
individuals with moderate degrees of cardio-
vascular disease are mentally impaired in any


HEALTH STATUS AND PSYCHOLOGICAL PERFORMANCE

on a single “speed” factor, so the scores were all
weighted appropriately and added to produce
a single “composite speed score.”

4, The Halstead Tactual Performance Test
(Halstead, 1947; Reitan & Shipley, 1963).
This test is an excellent indicator of organic
brain impairment (Reitan, 1959).

5. The WAIS Block Design Test (Wechsler,
1955) with Ss given sufficient time to complete
all items.. This test is a modification of an earlier
one, the WB-I Block Design Test, which is a
good indicator of organic brain impairment
(Reitan, 1959).

REsutts

Speed tests—The composite speed scores
(weighted sum of standard Psychomet Tests,
Trail Making Tests, and WAIS Digit Symbol
Test) of Ss in Groups Ja, Illa, IIb, IVa, and
IVb are shown in Figure 1, by age, together
with lines connecting their means. Groups IIIa

+3

+2

+1

Composite Speed Scores in & Units

279

and IIIb (arteriosclerotic disease groups) are
plotted as a single group. The ordinate values
correspond to the standard deviation for all
healthy Ss’ scores.

Because most of these various subgroups were
rather small and were irregularly scattered
among the various age levels and because the
variance of the various health groups seem to
be heterogeneous, the differences between means
of the healthy group and each of the groups
with pathological conditions were tested in the
following manner: a straight line was fitted to
the means of the healthy Ss aged 35-59. This
line was taken as the “baseline” for all scores in
the 35-59 age range; that is, this line defines a
score of “zero” in all of these age levels for all
Ss, healthy or otherwise. The variance of
healthy Ss aged 35-59 around this line was com-
puted and called unity, The mean and stand-
ard deviation of the healthy Ss thus were 0.00

=34 35-39

40-44

45-49 50-54
AGE

55-59

Fig. 1. Distributions of individual composite speed scores (in @ units) by age for healthy Ss (ll —— ll),
Groups Ila and IIb combined (C(===(), Group IVa (S] ——- —— N), and Group IVb (....- fl).



HEALTH STATUS AND PSYCHOLOGICAL PERFORMANCE 281
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Mean Reaction Time in Seconds of Healthy Subjects

Fig. 2. The abscissa represents the mean time required by a healthy S per reaction in a serial choice reaction
time test, or per response in a paper and pencil test. The mean time per reaction by Ss in Groups IIIa, IIb, and

IVa combined is plotted as a percentage of the mean time per reaction on the test by a healthy S. I -IX
Psychomet Tests; A, B—Trail making tests; D, digit symbol test.
Table 3. Mean Performances on the TPT and Block Design Tests for Healthy Subjects and for
Subjects with Cardiovascular Disease (Groups IIa, IIIb, and IVa Combined).
actual Performance Test Block Design Test
‘Totals Times Wars

Ago Time 3rd Trial Shapes Locations Point Times

(Yrs) N Geo) Gee.) __ Recalled Recalled N Score ——_(Bee.)
20-34 Healthy 146 480 cs 1d 5.7 M5 418 250

ov - _ = = = = = —

35-30 Healthy a 4m of at 5.5 8 43.7 245

ov 4 43 49 5.5 3.2 3 41.0 450
40-44 Healthy 143 530 109 74 AT 122 41.0 291

oy 19 55 ua TA 5.0 u 36.8 378

45-49 Healthy 55 590 16 7.6 4.8 aT 38.6 340

cv 10 710 168 6.1 27 10 39.3 370

50-54 Healthy 38 025 18 Ta 41 38 38.8 372

ov 16 830 164 64 3.6 15 36.0 410

55-59 Healthy B 758 167 6.2 3.9 19 39.1 340

ov 2 835 200 6.8 3.1 9 33.0 534

Means of

Cerebrovascular Ss Healthy 29 595 18 74 4.6 38.8 350
and healthy Ss of cv 9 878 208 6.2 34 35.9 485

same age distribution

‘Time scores are geometric means, in seconds.



284

gross sense. On the WAIS Digit Symbol and
Block Design tests, for which standardization
data are available (Wechsler, 1955), these car-
diovascular disease Ss, while inferior to the
healthy Ss, still did substantially better than
would be expected from like-aged individuals
drawn at random from the whole population.

The major import of the present results is
that substantial parts of the mean “age changes”
found in cross-sectional studies of psychological
performance might better be attributed to dis-
ease processes which are not inexorably bound
up with age, but are merely positively correlated
with age than to age itself. The incidence of
cardiovascular diseases and their increase with
age are high enough to account for much of the
reported downward trends of mean psychologi-
cal test scores with age. For example, White,
Edwards, and Dry (1950) reported important
degrees of coronary arteriosclerosis in about
20% of males aged 35, 50% of those aged 45,
and 75% of those aged 55. The incidence curve
declines with age after 55 because of a rising
death rate. It need be assumed only that the
progressively older age samples in a typical
study of psychological performance contain pro-
gressively higher percentages of the kind of
mild-to-moderate cardiovascular disease Ss
studied here, in order to predict an appreciable
part of the typical “aging effect.”

There is no reason at present to conclude that
downward trends of performance with age after
maturity are entirely attributable to extrinsic
disease processes; on the contrary, the strictly
healthy Ss in the present study produced mild
downward age trends as may be seen in Figure
1 and-Table 3. Nevertheless, it would almost
certainly be extremely profitable to measure the
cardiovascular health status of Ss in any psy-
chological study of aging.

Summary

Psychological performance tests were given to
more than 600 men aged 23-59. All were in
nominally normal health. Mild to moderate de-
grees of cardiovascular disease, with apparent
cerebral involvement, were reliably asso-
ciated with slow and, to a lesser extent, poor
performance. It is concluded that this was not
an artifact of attitude or testing situation. Be-
cause cardiovascular disease is common in old
humans and its incidence increases very rapidly
after age 35, it is suggested that much of the
typical downward trend of performance with
age is a reflection of cardiovascular diseases
rather than of aging per se.

SPIETH

‘The author is grateful to Miss Sue Watkins for administering these
tests to the majority of the Ss, to Miss Ann Alderman for performing
the statistical tests, and to John Seipel, M.D., neurologist, for iden-
tifying neuropathological $s, so that they could be eliminated from
the study or assigned to the relevant subgroup.

REFERENCES

Anderson, D.: An evaluation of the fusion frequency of
flicker and related phenomenon. as indices of seden-
tary fatigue and/or levels of excitability of the central
nervous system. Ph.D. Thesis, Univ. of Minnesota,
Minneapolis, 1963.

Apter, N. S., W. C. Halstead, and R. F. Heimburger:
Impaired cerebral functions in essential hypertension,
Amer. ]. Psychiat., 107: 808-813, 1951.

Birren, J. E., R. N. Butler, S. W, Greenhouse, L. Soko-
loff, and M. R, Yarrow: Interdisciplinary relationshi
interrelations of physiological, psychological, and psy-
chiatric findings, in healthy men, Chap. 15 in: J. E.
Birren, R. N. Butler, S. W. Greenhouse, L. Sokoloff,
and M. R. Yarrow (Editors), Human Aging. U.
Govt. Print. Office, Washington, 1963, PHS Publ.
986, pp. 283-305.

Birren, J. E., K. F. Riegel, and D. F. Morrison: Age
differences in response speed as a function of con-
trolled variations of stimulus conditions; evidence of
a general speed factor. Gerontologia, 6: 1-18, 1962.

Birren, J. E., and W. Spieth: Age, response speed and
cardiovascular functions, J. Geront., 17: 390-391, 1962,

Enzer, N., E. Simonson, and S. S. Blankstein: Fatigue
of patients with circulatory insufficiency, investigated
by. means of fusion frequency of flicker. Ann. intern.
Med., 16: 701-707, 1942.

Halstead, W. C.: Brain and intelligence. Univ. Chicago
Press., Chicago, 1947, xiii, 206 pp.

Reitan, R. M.: Intellectual and affective changes in es-
sential hypertension, Amer, J. Psychiat., 110: 817-824,
1954,

Reitan, R. M.: Certain differential effects of left and
right cerebral lesions in human adults, J. Comp.
physiol. Psychol. 48: 474, 1955,

Reitan, R. M.: Validity of the Trail Making Test as an
indicator of organic brain damage. Percep. & motor
Skills, 8: 271-276, 1958.

Reitan, R. M.: Effects of brain damage on a psycho-
motor problem solving task. Percep. & motor Skills,
9: 211, 1959.

Reitan, R. M,, and R, E. Shipley: The relationship of
serum cholesterol changes to psychological abilities,
J. Geront., 18: 350-357, 1963,

Simonson, E., and N. Enzer: State of motor centers in
circulatory insufficiency. Arch. intern. Med., 68: 498-
512, 1941.

Snedecor, G. W.: Disproportionate subclass numbers.
The R x 2 table. Chap. 11, Sec. 11.11 in: Statistical
Methods. Iowa St. College Press, Ames, 1946, 4th Ed.,
pp. 289-293,

Spieth, W.: Slowness of task performance in cardiovas-
cular diseases. In: J. E. Birren and A. Welford (Edi-
tors), Biological Bases of Age Changes in Speed of
Behavior. Charles C Thomas Co., Springfield, Ill.,
1964, (in press).

Wechsler, D.: Wechsler Adult Intelligence Scales. Psy-
chological Corp., New York, 1955, 110 pp.

White, N. K,, J. E. Edwards, and T. J. Dry: The rela-
tionship of the degree of coronary atherosclerosis with
age, in men. Circulation, N. Y., 1: 645, 1950.

*U.S. GOVERNMENT PRINTING OFFICE:1992-661-063/60003


AM 64-4

CARDIOVASCULAR HEALTH STATUS, AGE,
AND PSYCHOLOGICAL PERFORMANCE

OFFICE OF AVIATION MEDICINE
FEDERAL AVIATION AGENCY



282

(scrambled large or small digits or letters, or
colors-plus-symbol) and the Digit-Symbol Test
all were reliable discriminators in all compari-
sons; the Trail Making Tests were less so, espe-
ciallly for age. Because of the extreme brevity
of some of these tests, some pairs of tests were
combined to make scores, which in most cases
were based on at least 40 seconds of perform-
ance. These combinations and their associated
t-values for various comparisons are shown in
Table 2. The health-status comparisons are
based on age-adjusted scores. Old healthy Ss
were slower than young healthy Ss, and Ss with
pathological conditions were slower than like-
aged healthy Ss on all tests.

The relative slowing of the Ss with cardio-
vascular diseases (Groups IIIa, IIIb, and IVa)
is shown in Figure 2. The Psychomet Tests are
represented by Roman numerals connected by
lines, and the paper and pencil speed tests by
letters. As may be seen, the Ss with cardiovas-
cular disease tended to take a disproportionately
longer time than normal Ss on the more com-
plex reactions.

The Halstead Tactual Performance Test
(TPT).—Four scores were derived from TPT
performance: total time required to complete
the task three times, time required on the third
trial, and also number of shapes, and number
of locations drawn in the untimed recall test
which followed the three completions of the
tactual task. The means of these scores by age
and health categories are shown in Table 3.

The Ss with cerebrovascular disease (Group
V) were significantly poorer than like-aged
healthy Ss°6n all measures. F-tests were per-
formed, using only Ss aged 35-59, between the
healthy group, and Groups IIIa, IIIb, and IVa
combined to form a single group. (It was ap-
parent by inspection that the Ss with rheumatic-
congenital defects [Group II] and the medi-
cated hypertensive volunteers [Group IVb]
were not significantly different from the healthy
group.) The F-test technique used (Snedecor,
1946) takes account of the disproportionate age
distribution of number of cardiovascular and
healthy Ss. There was a highly significant in-
crease, with age, in total time required (P <
0,001) and in time required on the third trial
(P < 0.005). Older $s recalled significantly
fewer block shapes (P < 0.002) and insignifi-
cantly fewer block locations (0.20 > P >
0.10) than younger Ss. *

SPIETH

The combined group of Ss with cardiovas-
cular pathological conditions compared with
healthy Ss, required significantly more total
time (P < 0.025), and were slower on the
third trial, but at a borderline level of statisti-
cal significance (P < 0.05). They recalled
fewer block shapes, at a borderline level of
statistical significance (P < 0.05), and were
insignificantly poorer at recalling block loca-
tions (0.20 > P > 0.10) in comparison with
the healthy Ss.

Modified WAIS Block Design Test—Mean
performance scores are given in Table 3. The
healthy Ss’ scores averaged more than one
standard deviation above the estimated means
for the whole population at various ages as
given by the quite extensive standardization
data (Wechsler, 1955) for this test. The per-
formance of the cardiovascular Ss, while below
that of the healthy Ss of like age, averaged al-
most a full standard deviation above the popu-
lation mean. No attempt was made to analyze
mean differences among these point scores be-
cause of the pronounced ceiling effect in the
distribution of these scores. In order to obtain
continuously-distributed measures, each $’s
score was taken as the logarithm of the sum of
times required to perform the last four (and
most difficult) items on this test. Groups Ib, II,
and IVb performed very like the healthy Ss.
Groups IIIa, IIIb, and IVa combined were com-
pared with healthy Ss aged 35-59 in a health-
by-age F technique which corrects for dispro-
portionalities of age by health category (Snede-
cor, 1946). The increase of the time score with
age was significant (P < 0.001), and the car-
diovascular Ss were slower than like-aged
healthy Ss at a borderline level of statistical
confidence (P<0.05).

Discussion

Could these results be attributed to different
degrees of stress which the clinical testing situ-
ation may have produced in members of differ-
ent subgroups? I think they could not, at least
for the normotensive individuals: the “false
positive” Ss in Group Ib, who had the most
reason to be emotionally distressed by the clin-
ical situation, performed as well as the large
comparison Group Ia, while among the normo-
tensive arteriosclerotic Ss, the presumably more
relaxed members of Group IIIb performed as
poorly as did the presumably more stressed
members of Group IIIa.


Cardiovascular Health Status, Age, and
Psychological Performance’

AS IMPORTANT PROBLEM in the psychology of
aging is the extent to which poor or slow
performances are associated with age-correlated,
controllable diseases rather than with “aging”
per se. Several published studies (see Discus-
sion) indicate that middle-aged men with es-
sential hypertension or coronary heart disease
perform more poorly than like-aged controls on
a variety of tests and tasks. The present study
contrasts task performance scores of healthy
men with scores of men who live normal lives
and are in nominally “normal” health, but who
have cardiovascular diseases with mild to mod-
erate degrees of symptoms. The scores of men
who presented histories or symptoms of cere-
brovascular involvement are treated separately.

Mareriats AND METHops

Subjects—Federal law requires that civil
aviation pilots and air traffic control specialists
pass physical examinations periodically in order
to practice their specialties. Persons needing
physical certification may go to any of about
6,000 private physicians in the country who are
licensed to certify them, or to the Federal Avia-
tion Agency’s Georgetown Clinical Research
Institute in Washington, D. C., where these
data were gathered. Also, men who are refused
certification by a private physician may receive
an “appeal” examination at this Clinic. Men
were assured that they would be judged only on
the standard, legally-prescribed physical exami-
nation, and were asked to volunteer for the
more elaborate research tests and measures, in-
cluding the psychological tests. Fewer than 1%
declined. Most of the volunteers were FAA
employees and most are or have been pilots or
resented at the 1962 Annual Meeting of
the Gerontological Soeiety, Miami; at a conference on the, Biological
Bases of Age Changes in Speed of Behavior at St. John’s College,

Cambridge University, 1963; and the Sixth International Congress of

Gerontology, Copenhagen, .
Georgetown Clinical Research Institute, Federal Aviation Agency,

‘Washington, D. C.

1 Parts of this report were

Reprint from Joumal of Gerontology, Vol.

Walter Spieth, Ph.D.’

air traffic controllers, or both. Nearly all come
from the highest one-fourth of the population
in terms of occupational status and education.
Approximately one-half were given the WAIS
Arithmetic and Vocabulary scales (Wechsler,
1955); almost none scored below the population
mean, and most fell one standard deviation or
more above it on both scales. The majority of
these Ss were admitted to training in their avia-
tion specialties on the basis of entrance test-
batteries, which usually contained tests of both
perceptual-motor speed and spatial form-per-
ception abilities. All Ss were between the ages
of 23 and 59; most of Ss of major interest in this
study fell in the age range 35-59. All were
white. From nearly 800 dossiers of Ss aged 59
or younger, the Institute’s neurologist or other
examining physicians eliminated most Ss who
showed appreciable symptoms of central neuro-
pathology. Most Ss with other miscellaneous
pathological conditions were also eliminated.
A cardiologist, W. R. Scarborough, M.D., of this
Clinic, formed the following groups from the
remaining dossiers:

Ta. Strictly healthy Ss (N=560) all of whom
actively volunteered to come to the Clinic.
None had been referred by another physician.
Of these, 339 were aged 35-59.

Ib. “False Positive” Ss (N= 16) who had
been referred to the Clinic for further evaluation
and were thus extremely concerned about the
outcome of the examinations, but were later
judged sufficiently healthy to fly or work air
traffic control positions.

IL Ss (N=22) with stable mild rheumatic
or congenital cardiovascular defects. Many of
these were active volunteers, although some
were referred.

Illa. Ss (N=47) with somatic arteriosclerotic
or coronary heart disease. All were mild or
moderate cases; that is, all fell into American

19, No. 3, July, 1964—Printed in U.S.A. 277



278

Heart Association categories IA or IB. All
were referred to the Institute by other physi-
cians. All were normotensive, and none showed
independent clinical evidence or history of cere-
brovascular disease or impairment. A majority
had evidence and histories of myocardial in-
farction, none less than 6 months prior to the
examinations. All were recovered and regularly
employed.

IVa. Ss (N=17) with hypertension or hy-
pertensive cardiovascular disease in mild or
moderate.degree (AHA class IA or IB), with
blood pressures persistently higher than 140/90.
None showed clinical evidence or histories of
cerebrovascular disease or impairment.

V. Ss (N=9) presenting history or clinical
symptoms of cerebrovascular disease.

None of the foregoing Ss had taken drugs on
the day of the examination or for several days
before the examination, and most had not taken
drugs for several weeks or more before the ex-
amination.

Most individuals in group Ia were volunteers
who had no particular reason to be anxious in
the clinical situation. In contrast, many of the
individuals in Groups Ib, IIa, [Va, and V, and
some in Group II had reason to be anxious or
emotionally troubled about the outcome of their
physical examinations, although those few who
seemed emotionally upset were excluded from
this study.

In order to control for possible differences in
the emotional states between Ss in Group I and
in the other aforementioned groups, volunteers
were recruited from fully employed FAA offi-
cials who were not seeking medical certification,
through the kind cooperation of Bernard J.
Kramer, M.D. They were enrolled in an inde-
pendent, executive health program and had
been diagnosed by Dr. Kramer as suffering some
cardiovascular disease with mild or moderate
symptoms (AHA categories IA or IB). Almost
100% cooperation was obtained. Unfortunately,
the small size and the heterogeneity of this
sub-population permitted the formation of only
two groups:

IlIb. 12 individuals with history and evi-
dence of old myocardial infarctions, coronary
heart disease or arteriosclerosis, without hyper-
tension. None had taken drugs for several
weeks preceding the tests.

IVb. 13 individuals who had been diagnosed
as hypertensive by private physicians or at the
independent executive health clinic, and whose

SPIETH

blood pressures were being kept below 140/90
at the time of testing by various drug treat-
ments. Two took central nervous system de-
pressants and the others took vasodilating drugs.

None of the Ss in Groups IIIb or IVb had
histories or symptoms of cerebrovascular dis-
orders. They were given only the psychological
tests, without physical examination, at this
Clinic.

All Ss in Groups IIIa, IIIb, IVa, IVb, and V
were 35-59 years old.

Tests.—Ss were given the following tests, us-
ually in a single session, in order 1, 2, 3, and
also were given tests 4 and 5 when possible.

I. WAIS Digit-Symbol Substitution Test
(Wechsler, 1955). An earlier version of this
test was found to be a good indicator of organic
brain dysfunction (Reitan, 1955).

2. Trail Making Tests A and B, which are
good indices of organic brain impairment (Rei-
tan, 1958).

3. A battery of stimulus-matching, serial re-
action-time tests on the Psychomet Apparatus
(Birren, Riegel, & Morrison, 1962), with the
original tests 2-9, plus several new variations.
The device has a 14”-wide row of 10 stimulus
windows in front of the S, with 10 response but-
tons in a corresponding row a few inches lower,
and labels just above the buttons. In all tasks,
when the S pressed the “start” button, a stimu-
lus window lighted and gave a cue indicating
which of the 10 buttons should be pressed.
When S pressed the correct button, it extin-
guished the stimulus and simultaneously lighted
another one, etc., to make a continuous serial
choice reaction-time task. A subtest consisted
of two sets of 10 reactions. The tests were I)
pressing the button directly under the stimulus
light; II) finding the button labeled with stim-
ulus digit “j” and pressing it, when the 10 but-
tons were labeled in order—l, 2, 3,.. j .. 10;
III) like II, but with the buttons labeled in a
scrambled order; IV) and V) like II and III,
with letters rather than digits; VI) and VII)
like III and IV but with large (54”) block
symbols; VIII) stimulus-matching as above, but
with a stimulus one of five colors with either
an “X” or an “O” in it; IX) matching Y-shaped
patches, with a red, a yellow, and a blue pie-
shaped segment in each.

In all of the above tests, $ was told to go as
fast as possible. A previous factor analysis of
some of these data (Birren & Spieth, 1962) in-
dicated that all three sets of tests loaded heavily