Technical Report Documentation Page 

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. 

FAA-AM-76- 14 

4. Title and Subtitle 5. Report Date 

THREE STUDIES OF MOTION SICKNESS SUSCEPTIBILITY 6. Performing Organization Code 

8. Performing Organization Report No. 

7. Authorl s} J • Michael Lentz~ Ph.D. 

William E. Collins Ph.D. 9. Performing Organi zotion Nome and Address 10. Work Unit No. (TRAIS} 

FAA Civil Aeromedical Institute 

P.O. Box 25082 11. Contract or Grant No. 

Oklahoma City, Oklahoma 73125 13. Type of Report and Period Covered 

12. Sponsoring Agency Nome and Address 

Office of Aviation Medicine OAM Report Federal Aviation Administration 

800 Independence Avenue, s.w. 14. Sponsoring Agency Code 

Washinqton D.C. 20591 15. Supplementary Notes 

This research was conducted under Tasks AM-D-75-PSY-54 and AM-D-76-PSY-62. 

16. Abstract 

The incidence of motion sickness in a large (N = 3,618) college population was determined by means of a questionnaire. Significantly greater proportions of men than 

women had low susceptibility scores; significantly greater proportions of women had 

high susceptibility scores. Comparisons of MSQ scores were made with other selfassessments, age changes, motion experiences, familial susceptibility, use of motion 

sickness medication, muscular coordination, willingness to participate in motion 

experiments, flying experience, phobias, visual motion effects, and use of alcohol. 

MSQ scores were next used to select groups of highly susceptible and nonsusceptible 

subjects (12 men and 12 women in each group) to assess the relationships of motion 

sickness susceptibility to laboratory measures of vestibular function and duration of 

the spiral aftereffect. When subjective alertness levels were controlled, there was 

no enhancement of eithfr elicited nystagmus or turning sensations in comparing 

susceptible with nonsusceptible individuals. MSQ scores were also used to select an 

additional 25 men and 25 women for each of the two categories of susceptibility. 

These subjects were tested on at least three but not more than six of the following 

eight tests: Floor Ataxia Test Battery, State-Trait Anxiety Inventory, Menstrual 

Distress Questionnaire, Cornell Medical Index, Cornell Word Form, Eysenck Personality 

Inventory, Rotter Internal-External Locus of Control Scale, and the 16 Personality 

Factors test. The consistent and significant patterns of results from those tests 

are discussed in terms of the personality characteristics that generally distinguish 

those highly susceptible from those nonsusceptible to motion sickness. 

17. Key Words 18. Distribution Statement 

Motion Sickness Document is available to the public 

Vestibular Function through the National Technical Information 

Personality Service, Springfield, Virginia 22151 

Behavior 

19. Security Classil. (of this report} 20. Security Classif. (of this page} 21. No. of Pages 22. Price 

Unclassified Unclassified 

Form DOT F 1700.7 (8-72} Reproduction of completed page authorized 
Acknowledgment 

We gratefully acknowledge the assistance of Gregory N. Constant, Linda 

Foreman, and Cissy Lennon in the conduct of the study; of Jean Grimm 

and Cindy Mayes for the scoring of tests; of LaNelle Murcko for editorial 

assistance; and of Dr. Earl Folk, Peter L. Nelson, and Rosalie Melton for 

statistical aid. This study was conducted in the Aviation Psychology Laboratory of the Civil Aeromedical Institute and was funded in part by a grant 

from the Department of Psychiatry and Behavioral Sciences, University of 

Oklahoma Health Sciences Center. 
Table of Contents 

Motion Sickness Susceptibility and Related Behavioral CharacterPage 

istics in Men and Women by J. M. Lentz and W. E. Collins ____ 1 

Nystagmus, Turning Sensations, and Illusory Movement in Motion 

Sickness Susceptibility by J. M. Lentz ------------------------- 11 

Some Psychological Correlates of Motion Sickness Susceptibility by 

W. E. Collins and J. M. Lentz ------------------------------- 19 

MOTION SICKNESS SUSCEPTIBILITY AND RELATED BEHAVIORAL 

CHARACTERISTICS IN MEN AND WOMEN 

J. Michael Lentz, Ph.D. 

"William E. Collins, Ph.D. 

I. Introduction. 

Of the multiple methods used to assess motion 

sickness susceptibility,9 the questionnaire approach has been shown to yield reasonably valid 

results2 and is clearly the easiest technique to 

employ. Several motion sickness history questionnaires4 7 11 have been considered for military 

application, primarily to predict attrition from 

flight training programs. In particular, the 

Pensacola Motion Sickness Questionnaire7 has 

been used in a multiple prediction formula to 

estimate a candidate's likelihood of success in 

naval flight training. 

In other than military settings, where individuals form relatively select groups because of 

various types of preliminary screening, motion 

sickness questionnaires (MSQ) have received 

only meager use. The most noteable example of 

a nonmilitary MSQ is documented in a study 

by Reason,t 2 who administered a short motion 

sickness questionnaire to 150 men and 150 women 

at the University of Leicester. From this 

sample, he concluded that women reported a 

greater incidence of past motion sickness than 

did men and that both sexes reported a lower 

incidence of motion sickness following the age 

of 12. 

In general, MSQ's have not been subjected to 

reliability tests and have rarely been used to 

examine specific features associated with motion 

sickness susceptibility. 

The current investigation consisted of two 

phases, the first o£ which determined how motion 

sickness susceptibility was distributed in a relatively large college population. This survey was 

similar to that reported by Reason,' 2 although 

it encompassed a much larger sample and was 

1 

used to provide a source of potential subjects for 

a laboratory study of vestibular function. 8 ·The 

second phase, which included a test-retest 

sample, was similar to our first survey but also 

incorporated sets of items designed to assess the 

degree to which certain behavioral and other 

characteristics might be associated with motion 

sickness susceptibility. 

II. Procedure. 

A. MSQ-1. MSQ-1 was completed by 2,432 

students in undergraduate classes at three local 

universities. The students ranged in age from 

16 to 62 (mean=22.0); only 7 percent were 30 

years of age or older. Although test taking was 

not mandatory, almost all classes had 100-percent 

participation. 

MSQ-1, a modified version of a questionnaire 

developed by Birren/ was scored on the basis of 

responses to 20 items concerned with the individual's lifetime tendency to develop motion 

sicknessin a variety of situations, such as in automobiles, trains, roller coasters, etc. (see Table 2 

for a list of all 20 situations). The possible 

answers for each item and the numerical weights 

used to score those answers were : never sick ( 0) , 

rarely sick ( 1) , occasionally sick ( 2) , often sick 

(3), and almost always sick (4). An individual 

·could also indicate no experience in a particular 

situation. 

Following the 20 basic items, MSQ-1 had three 

additional questions: In general, how susceptible 

to motion sickness are you~ Have you ever taken 

a medication like Dramamine for motion sickness? Would you be interested in being a paid 

volunteer in an experiment that involves very 

mild motion ? 
B. MSQ-2. MSQ-2, developed as a more comprehensive version of MSQ-1, consisted of three 

sections. The first section, similar to MSQ-1, 

assessed the frequency of motion sickness as well 

as the degree of experience in 20 motion situations. The second section assessed motion sickness tendencies in the individual's immediate 

family as well as the individual's general susceptibility to motion sickness and how it had 

changed since the age of 12, and it included other 

items on muscular coordination, phobias, visual 

motion, flying experiences, and willingness to participate in a motion experiment. The third section inquired about the individual's experience 

with alcohol. 

Students, ranging in age from 16 to 56 (mean= 

20.5), in undergraduate classes at a state university were subjects; less than 4 percent were 

30 years of age or older. MSQ-2 was administered on a test-retest basis with an interval of 

6 to 8 weeks between sessions. The students were 

instructed to complete all three MSQ sections 

on their original testing and only the first section of 20 items on the retest. The original test 

was completed by 1,072 students and 548 completed the second test (no attempt was made to 

retest all classes) ; a total of 434 completed both 

forms. Thus, responses' were available from a 

total of 1,186 students for the first section of the 

MSQ-2 questionnaire and from 1,072 students 

for the second and third sections. 

III. Statistical Analyses. 

Responses to items were omitted inconsistently 

and only occasionally. Two types of statistics 

were applied to the data: correlation coefficients 

and X 2 tests of significance of differences. Differences were considered significant at probability levels of .05 or less. 

IV. Results. 

A. Distribution of Scores. Data from MSQ-1 

and MSQ-2 were combined into a single distribution. Mean scores ranged from 0 to 3.65 and 

were arbitrarily partitioned into nine categories. 

There were significant differences (p<.001) in 

the distribution of scores for men a~~ women 

with a greater percentage of men than women 

in the low (least susceptible) MSQ categories 

and, conversely, a smaller percentage of men in 

the high (most susceptible) MSQ categories. 

The distributions of scores for men, women, and 

both sexes combined appear in Table 1. For 

some later analyses, subjects were divided into 

three degree-of-susceptibility groups based on 

the nine response categories of MSQ scores. The 

nonsusceptible subjects were those individuals in 

MSQ category 1; the moderately susceptible 

group included individuals in categories 2, 3, 4, 

and 5; the very susceptible group comprised individuals in MSQ categories 6, 7, 8, and 9. 

B. Test-Retest Reliability. MSQ-2 was conducted on a test-retest basis. Based on 434 subjects the derived reliability coefficient for mean 

scores on the 20-item section was 0.84. The questionnaire thus yields consistent inf?rmation. 

C. Self-Assessments. Mean MSQ scores from 

the 20 motion situations were compared with the 

subjects' own estimates of their motion sickness 

susceptibility (In general, how susceptible to 

motion sickness are you: extremely, very, moderately, minimally, not alH). The mean MSQ 

scores for all subjects and their estimates (scored 

0--4) of susceptibility were significantly correlated (r=0.70). Many susceptible subjects were 

somewhat inclined to underestimate their degrees 

of susceptibility relative to their mean MSQ 

scores. 

TABLE 1. Distribution of Subjects by HSQ Score:s 

Category 

(Score) 

Men 

Women 

All 

N 

1 

(0) 

520 

266 

786 

' 

27 

16 

22 

2 3 4 5 6 7 8 9 

(.01-.24) (.25-.49) (.50-.74) (.75-.99) (1.00-1.24) (1.25-1.49) (1.50-1.74) (1.75 +) 

Total 

N ! N ! .!! .! N .! N .! .!! .! " .! .!! .! -"-

731 37 405 21 152 8 63 3 43 2 22 1 10 0 6 0 1,952 

488 29 361 22 237 14 132 8 95 6 44 3 15 1 28 2 1,666 

1,219 34 766 21 389 11 195 5 138 4 66 2 25 1 34 1 3,618 

2 
D. Susceptibility Indew. A motion sickness 

susceptibility index was developed to provide a 

comparison between the 20 items involving motion. The susceptibility index was derived for 

each MSQ item (ignoring "no experience" answers) by calculating the mean score of all subjects who answered the item by using the 

following weights: 0 =never sick, 1 =rarely sick, 

2=occasionally sick, 3=often sick, 4=almost 

always sick. Susceptibility index scores based on 

all subjects tested are presented in Table 2. An 

item with a high susceptibility index score is 

more likely to induce motion sickness than is an 

item with a low susceptibility index score. For 

instance, from Table 3 one can conclude than an 

individual is most likely to report the strongest 

degree of motion sickness susceptibility to carnival devices because those items had the highest 

susceptibility index scores in both subject groups. 

E. Ewperience With Forms of Motion. Experience in motion situations for each of the 

three degree-of-susceptibility groups is shown in 

Table 3. Inspection of the data reveals that a 

significant overall difference (p< .001) was almost 

entirely due to the divergent scores from the 

very susceptible subjects; they reported fewer 

experiences in these motion situations. Men and 

women did not differ significantly. 

Iteoo 

1. 

2. 

3. 

~. 

5. 

6. 

7. 

8. 

9. 

10. 

11. 

12. 

13. 

14. 

15. 

16. 

17. 

18. 

19. 

20. 

TABLE 2. A Notion Sickness Sus-tibllity Index. Very Sus-tlble 

Subjects Are Those Whose Mean M5Q Scores for All 20 ItWere 1. 00 or Higher. 

Susceptibility Index 

Very 

All Susceptible 

Subjects Subjects 

(11=3,618) (H=25l) 

Large Ships 0.61 2.26 

Sull Boat'~ 0.26 1.16 

Merry·go-rounds 0.59 2.1~ 

Roller Coasters 0.65 2.21 

Ferris Wheels 0.~7 2.01 

Other Carnival Devices 0.98 2.56 

AutOIIObUes (as a passenger) 0.53 1.86 

Buses 0.38 1.7~ 

Trains 0.16 0.98 

Subways 0.11 1.10 

Streetcars 0.08 0.98 

Airplanes ( ... u or large) 0.~ 1.91 

Elevators 0.33 1.52 

Swings 0.32 1.57 

H~s 0.07 0.69 

Ring and Bar Cywuost1cs 0.16 0.85 

ScMiersaults 0.30 1.28 

Rollerskat1ng 0.05 0.44 

Ice Skating 0.04 0.33 

Dancing 0.06 0.34 

TABLE 3. The Frequencies in Percentages With Which the Four 

Experience Categories Were Checked for the 

20 Motion Items (HSQ-2) 

Number of Ex~eriences 

0 1-3 4-9 10+ Total Total N 

Group ($) ($) ($) ($) Experiences Subjects 

Nonsusceptible 18 13 12 56 4,816 241 

Moderately Susceptible 18 l4 12 55 16,197 814 

Very Susceptible 24 17 14 45 2,595 131 

All Hen 19 14 12 54 12,756 640 

All Women 19 14 12 54 10,852 546 

3 
F. Reported Changes in Susceptibility With 

Age. Responses to items concerning how the individual's tendency to develop motion sickness 

may have changed since the age o£ 12 are presented in Table 4. Analysis o£ the data indicated a significant sex difference (p < .001) with 

women reporting more increases and £ewer decreases in susceptibility since the age o£ 12 than 

did men. In comparing susceptibility groups, 

the majority o£ nonsusceptibles reported no 

change (although they denied any motion sickness experiences, 4 o£ 213 respondents indicated 

an increased tendency to develop motion sickness, 

and 25 others indicated a decreased tendency) 

whereas most o£ the moderately and very susceptible individuals reported a change in susceptibility (p < .001) with very susceptible subjects 

reporting the greatest percentage o£ increases 

( 19 percent). More than 40 percent o£ the latter 

two groups indicated a decrease in susceptibility 

since the age o£ 12. 

G. Familial Susceptibility. Estimates o£ motion sickness susceptibility in family members 

are presented in Table 5. This set o£ questions 

required the individual to estimate the motion 

sickness susceptibility o£ his or her parents and 

siblings. There were significant differences between susceptibility groups (p<.001 in each 

case) £or reported susceptibility o£ sister ( s), 

brother ( s) , mother, and £ather. In each instance, highly susceptible individuals more often 

reported having susceptible siblings and parents. 

In comparing differences between men and 

women, women more often reported having susceptible siblings (sister ( s), p < .05; brothers ( s), 

p<.001) than did men; however, this sex difference was not evident in responses to parents' 

susceptibility. 

H. Use of Motion Sickness Medication. MSQ1 inquired about the use o£ anti-motion-sickness 

drugs. 0£ the individuals tested, 16 percent o£ 

the men and 27 percent o£ the women reported 

they had taken a medication like Dramamine 

£or motion sickness (Table 6). -women were 

more likely to take medication than were men 

(p<.001) and, as susceptibility increased, so did 

the frequency o£ taking anti-motion-sickness 

medication (p < .001). 

I. Muscular Coordination. Subjects were asked 

to describe their muscular coordination on a fivecategory response scale (very poor to excellent). 

Men rated their coordination significantly better 

4 

(p<.001) than did women. There were no 

statistically significant differences between susceptibility groups, but there was a tendency £or 

very susceptible subjects to rate themselves lower 

than did moderately susceptible or nonsusceptible 

subjects (Table 7). 

J. Willingness to Participate in Motion Experiments. Both MSQ-1 and MSQ-2 inquired 

about the subject's willingness to be a paid participant in mild motion experiments (Table 8). 

Results differed £or the two administrations; 

specifically, £or MSQ-1 there were no significant 

differences £or sex or £or susceptibility groups 

while MSQ-2 yielded significant differences £or 

both sex and susceptibility. The difference in 

findings is probably attributable to the time o£ 

year that the two questionnaires were administered. Specifically, MSQ-1 was given near the 

beginning of a school semester and MSQ-2, in 

the latter hal£ o£ that semester; the likelihood 

is strong that growing financial needs o£ the students dictated the change in willingness to be 

a paid volunteer. The increase £rom MSQ-1 to 

MSQ-2 in the proportion o£ subjects willing to 

be involved in a motion experiment was greatest 

£or the nonsusceptible subjects and least £or the 

very susceptible. It is worth noting that more 

than hal£ the subjects in each susceptibility category, including the very susceptible, were willing, 

£or pay, to participate in mild motion expBriments. 

K. Phobias, Flying, and Visual Motion. Table 

9 presents data based on a series o£ £our items 

£rom MSQ-2. Sex comparisons £or the £our 

items yielded the following results (p < .001 in 

each case) ; more men enjoyed movies with an 

emphasis on rapid motion, more men were pilots 

or had taken flying lessons, and more women 

were afraid o£ heights and o£ darkness. There 

were also significant differences between susceptibility groups on all four items (p<.OOl by 

X 2 in each case) : movies, flying lessons, heights, 

and darkness. However, nonsusceptible and moderately susceptible individuals did not differ on 

any o£ these items. Thus, very suscepti~le individuals can best be described as less likely to 

enjoy movies with an emphasis on rapid motion, 

less likely to have taken flying lessons, and more 

likely to £ear heights and darkness. The same 

description would pertain to women as compared 

with men. 
TABLE 4. The Percentages of Subjects by Croup and Sex Describing How Their General Tendency to 

Develop Motion Sickness Hay Have Changed Since Age 12 

Croup Increased No Change Decreased Don't Know Total N 

(I) (I) (I) (I) 

Nonsusceptible 2 68 12 18 213 

Moderately Susceptible 9 33 41 16 719 

Very Susceptible 19 21 44 16 ll6 

All Men 5 38 38 18 552 

All W0111en 14 39 33 15 496 

TABLE 5. Estimates by Group and Sex, in Percentages, of the Degree to Which 

Motion Sickness Was Evidenced in Family Members 

Often Number 

Never or of 

Family or Almost Don't Family 

Melllbers Group Rarely Sometimes Always Know Members 

(I) (I) (I) (I) Reported 

Nonsusceptible 61 16 1 22 231 

Moderately Susceptible 52 24 5 19 898 

Sister(s) Very Susceptible 23 34 9 33 160 

All Hen 48 20 3 29 663 

All Women 52 28 6 14 62£ 

Nonsusceptible 73 7 0 19 267 

Moderately Susceptible 63 14 2 22 890 

Brother(s) Very Susceptible 28 26 6 41 156 

All Hen 63 12 1 24 719 

All Women 58 16 3 23 594 

Nonsusceptible 60 23 3 .14 212 

Moderately Susceptible 48 31 6 15 717 

Mother Very Susceptible 29 36 17 18 ll5 

All Hen 47 30 6 16 546 

All Women 50 30 7 14 498 

Nonsusceptible 78 6 1 15 216 

Moderately Susceptible 71 12 1 15 711 

Father Very Susceptible 54 18 5 24 ll4 

All Hen 72 10 1 16 547 

All Women 69 13 2 16 494 

5 
TABLE 6. The Percentages of Subjects by Group and Sex Who Indicated 

Whether They Had Ever Taken Medication Like 

Dramamine for Motion Sickness 

Group Yes No 

($) ($) 

Nonsusceptible 4 96 

Moderately Susceptible 24 76 

Very Susceptible 52 48 

All Men 16 84 

All Women 27 73 

Total 

N 

543 

1,744 

132 

1,306 

1,ll3 

TABLE 7. The Percentages of Subjects by Croup and Sex as They Described Their Muscular Coordination 

Very Below Above 

Croup Poor Average Average Average Excellent ,.otal 

(I) (I) (I) (I) (I) N 

Nonsusceptible 0 4 36 39 20 216 

Moderately Susceptible 0 5 43 36 16 720 

Very Susceptible 1 9 45 34 10 ll6 

All Hen 0 2 33 41 23 5'ilL 

All Women 1 8 51 31 9 498 

6 
TABLE 8. The Percentages of Subjects by Group and Sex Who Indicated 

Whether They Were Interested in Being Paid Volunteers 

in an Experiment That Involved Very Mild Motion 

HSQ-1 HSQ-2 

Group Yes No Total Yes No 

(I) (I) N (I) (I) 

Nonsusceptible 58 42 539 78 22 

Moderately Susceptible 55 45 1, 734 73 27 

Very Susceptible 54 46 132 63 37 

All Hen 57 43 1,293 80 20 

All Women 55 45 1,112 65 35 

TABLE 9. The Percentages of Subjects by Croup and Sex Who Indicated Whether They Liked 

Movies That Emphasize Rapid Motion, Are Pilots or Have Ever Taken Flying Lessons, 

and Are Afraid of Heights or of Darkness 

Like movies with A pilot or have 

Total 

N 

213 

715 

115 

549 

494 

ra~id motion taken fl~ing lessons Afraid of heights Afraid of darkness 

Group Yes No Total Yes No Total Yes No Total Yes No Total 

(%) (%) N (%) (%) N (%) (~) N (~) (~) N 

Nonsusceptibles 82 18 211 11 89 216 21 79 213 7 92 215 

Moderately Susceptible 74 26 702 7 93 719 28 72 720 11 89 714 

Very Susceptible 44 56 113 3 97 115 51 49 115 30 70 112 

All Hen 85 15 539 H 89 554 21 79 552 5 95 551 

·All Women 57 42 487 3 97 496 37 63 496 20 80 490 

7 
L. Alcohol. The last six items on the MSQ-2 

questionnaire were concerned with the consumption o£ alcohol and specifically included a description o£ drinking habits (Table 10) and 

alcohol-induced hangovers (Table 11). From 

the results o£ Table 10, one can conclude that 

men drink more frequently and in larger quantities than do women (p < .001 in both cases) . 

In general, the data indicate the degree of motion sickness susceptibility is not significantly 

related to alcohol consumption, although there 

is a tendency for the more susceptible both to 

drink less often and to drink less on each 

occasion. 

In the descriptions of alcohol-induced hangovers, the frequency and severity of hangovers, 

as well as the general concern about having 

them, become significantly (p < .001 in each case) 

more prominent in individuals as susceptibility 

increases. In addition, men more frequently reported having hangovers than did women 

(p < .01), although women more frequently reported both that they worried about having a 

hangover (p<.05) and that they vomited or 

thought they were going to vomit following 

alcohol ingestion (p < .001). 

V. Discussion. 

Although most previous efforts have been directed toward determining the incidence of 

motion sickness in specific occupational populations (such as among pilot candidates or seagoing personnel) it is noteworthy that motion 

sickness affects a considerable number of people 

in the general population in relatively common 

situations. For example, our definition of very 

susceptible individuals as those whose mean 

motion sickness history questionnaire scores exceed 1.00 (see scoring procedure) accounts for 

8 percent of our surveyed population. Mor{)-

TABLE 10. The Percentages of Subjects by Group and Sex as They Described Their Drinking Habits 

Only one or Total two drinks Drink Drink Drink 

abstainer in 11 fe Rarely occasionally Often Total 

Item Group (\) (\) .J!.L_ (I) .J.!L H 

Description of Nonsusceptible 6 4 15 53 22 216 

drinking habits Moderately Susceptible 8 6 13 57 17 719 

Very Susceptible 4 12 19 48 16 115 

All Men 8 5 10 55 23 553 

All Women 6 7 18 55 13 497 

Three 

or more One time Two or One or two times 

Total or less three times times per 

abstainer per month per month per week week Total 

Item ~ (\) (\) (\) (\) ___.1!L H 

Frequency of Honsusceptible 8 20 24 34 13 216 

drinking Moderately Susceptible 11 21 28 28 ll 716 

Very Susceptible 11 30 26 24 8 115 

All Men 11 15 24 33 16 553 

All Women 10 30 30 24 6 494 

Total Two or Four or Six or abstainer One three five more Total 

Item Group (\) ill .J!.L_ (\) _l!L H 

Average amount Honsusceptible 8 14 36 24 17 215 

of drinks per Moderately Susceptible 10 14 40 26 9 716 

occasion Very Susceptible 10 19 40 22 9 115 

All Men 10 8 34 30 17 552 

All Women 9 22 45 21 3 504 

8 
TABLE ll. The Percentages of Subjects by Croup and Sex as They Described 

Aspects of Their Alcoholic Hangovers 

I tell Group Never 

(I) 

Have hangover Nonsuscept!ble 47 

after drinking Moderately Susceptible 40 

Very Susceptible 35 

All Hen 36 

All Women 47 

Worry about Nonsuscept!ble 78 

hangover when Moderately Susceptible 70 

drinking Very Susceptible 51 

All Hen 71 

All Women 68 

Vomited or Nonsuscept!ble 35 

felt like it Moderately Susceptible 27 

after drinking Very Susceptible 32 

All Hen 23 

All Women 36 

over, slightly more than 20 percent of our population had taken a medication like Dramamine 

for motion sickness. In an increasingly mobile 

world, the extent of the problem of motion sickness susceptibility can only become greater. 

Motion sickness history questionnaires provide 

an adequate approach to susceptibility det~rminations and have the advantage of quick administration with no sophisticated apparatus. In 

the present application, the t~st-retest reliability 

of MSQ-2 was of a magnitude sufficient to suggest good testing stability. Until the differences 

between susceptible and nonsusceptible individuals can be better defined, a prudent approach 

to several types of human research (e.g., vestibular, motion, and performance) would be to 

delineate motion sickness susceptibility for all 

subjects tested. This approach would allow 

better interstudy comparisons of results and 

might also provide an explanation for deviant 

result:s. 

Our findings confirm the report12 that proportionately more women than men report motion 

sickness. However, an unresolved question is 

whether this reported sex difference in susceptibility is based on physiological differences, on 

9 

About 

Half 

the 

Rarely Tille Frequently Always Total 

(I) (I) (I) (I) N 

43 8 1 1 210 

48 10 1 0 684 

42 12 10 0 113 

49 12 2 0 531 

44 7 2 0 476 

20 2 0 0 210 

25 4 1 0 682 

32 9 4 4 ll3 

24 4 1 0 529 

25 4 2 1 476 

61 3 1 0 211 

64 6 2 0 689 

46 10 10 2 112 

69 5 2 0 534 

53 6 3 1 478 

psychological differences, or on a combination 

of those two, or whether it is merely reflective 

of a socialization process in which it is more 

acceptable for women to report illnesses (in~luding motion sickness). Bawkin3 and Abe, 

Amatomi, and Kajiyama1 have suggested that 

susceptibility differences are genetically determined. The latter have reported that at age 3, 

girls suffered more frequently (12.1 percent) 

from motion sickness than did boys ( 6.5 percent). 

A potential hereditary factor in motion sickness 

susceptibility may be supported by our results, 

which indicate that, compared to nonsusceptibles, 

susceptible individuals more often report susceptible parents or siblings. However, susceptible 

people may be more inclined to attend to and 

be aware of such characteristics in their family 

members. 

Very susceptible individuals reported significantly fewer experiences with the 20 itemized 

motion situations than did nonsusceptibles. This 

probably reflects the simple fact that susceptible 

individuals avoid situations in which they are 

likely to become sick. Moreover, a little more 

than 40 percent of those who reported motion 

sickness experiences believed that their suscepti-
bility had decreased since age 12. This finding 

is in agreement with the results of a previous 

MSQ study12 and with the results of at least 

one experimental report. 5 Such a decrease in 

susceptibility with increasing age could be attributable to (i) avoidance of motion situations, 

(ii) a decrease in the physiological sensitivity 

of the vestibular sensory apparatus, or (iii) an 

increase in vestibular experiences with age and 

thus a learning-induced moderation of affect. 

The first possibility, an avoidance of motion situations, cannot account for the age-related reduction of demonstrated susceptibility shown by 

Chinn et al. wherein groups of subjects of different ages were exposed to the same motion 

stimuli. The second suggestion, a decrease in 

physiological sensitivity, is inconsistent with 

other work8 that indicates, at least with young 

subjects, no differences between nonsusceptible 

and very susceptible men or women in vestibular 

nystagmus or in turning sensations produced in 

the laboratory despite the continuing high level 

of susceptibility of the latter group. The third 

possibility, that experience acts as a moderator 

of vestibular responses, seems to be the best current explanation of the age-related reduction in 

motion sickness susceptibility. 

Since motion sickness can be induced by purely 

visual means,10 it was not surprising that a significantly greater percentage of susceptible individuals did not like movies with an emphasis 

on rapid motion. Moreover, extremely susceptible individuals had a greater fear of heights 

and of darkness than did their less susceptible 

counterparts. The relationship of phobias to 

psychosomatic disturbances suggests that additional psychological characteristics may be associated with motion sickness susceptibility. A 

possibly related datum is that very susceptible 

individuals reported they more frequently worried about having alcoholic hangovers. Although 

alcohol affects vestibular functioning6 and can 

produce undesirable effects similar to those encountered during motion sickness, there was no 

significant difference between our susceptible and 

nonsusceptible groups in the amount of alcohol 

consumed. However, in assessing the latter finding, one must consider the young age of our 

subjects and that their drinking habits may not 

be representative of other geographic regions. 

10 

Our data also indicate a number of significant 

sex differences related to motion sickness susceptibility. These findings suggest that behavioral profiles will differ for men and for women in 

relation to their degrees of susceptibility. In 

seeking to delineate characteristics of those prone 

to motion sickness, one must take into account 

these sex differences. 

References 

1. Abe, 1 K., M. Amatomi, and S. Kajiyama: Genetical 

and Developmental Aspects of Susceptibility to Motion Sickness and Frostbite, HUMAN HEREDITY, 

20 :507-516, 1970. 

2. Alexander, S. J., M. Cotzin, C. J. Hill, Jr., E. A. 

Ricciuti, and G. R. Wendt: Wesleyan University 

Studies of Motion Sickness: VI. Prediction of Sickness on a Vertical Accelerator by Means of a Motion 

Sickness History Questionnaire, JOURNAL OF 

PSYCHOLOGY, 20 :25-30, 1945. 

3. Bawkin, H. : Car-sickness in Twins, DEVELOPMENTAL MEDICINE AND CHILD NEUROLOGY, 

13 :310-312, 1971. 

4. Birren, J. E.: Psychophysiological Studies of Motion 

Sickness. Doctoral Dissertation, Northwestern University, Evanston, Illinois, 1947. 

5. Chinn, H. I., S. W. Handford, P. K. Smith, T. E. 

Cone, Jr., R. F. Redmond, J. V. Maloney, and 

C. McC. Smythe: Evaluation of Some Drugs in Seasickness, JOURNAL OF PHARMACOLOGY AND 

EXPERIMENTAL THERAPEUTICS, 108 :69-79, 

1953. 

6. Collins, W. E., D. J. Schroeder, and R. J. Hill: Some 

Effects of Alcohol on Vestibular Responses, ADVANCES IN OTO-RHINO-LARYNGOLOGY, 19:295-

303, 1973. 

7. Hutchins, C. W., and R. S. Kennedy: Relationship 

Between Past History of Motion Sickness and Attrition from Flight Training, AEROSPACE MEDICINE, 36 :984-987, 1965. 

8. Lentz, J. M.: Nystagmus, Turning Sensations, and 

Illusory Movement in Motion Sickness Susceptibility, 

AVIATION, SPACE, AND ENVIRONMENTAL 

MEDICINE, 47 :931-936, 1976. 

9. Money, K. E. : Measurement of Susceptibility to 

Motion Sickness. AGARD CP-109. Technical Editing and Reproduction, Ltd., London, 1972. 

10. Parker, D. M.: A Psychophysiological Test for Motion Sickness and Susceptibility, JOURNAL OF 

GENERAL PSYCHOLOGY, 85:87-92, 1971. 

11. Powell, T. J., A. M. Beach, J. R. Smiley, and N. C. 

Russell : Successful Prediction of Air Sickness in 

Aircrew Trainees, AEROSPACE MEDICINE, 33: 

1069-1076, 1962. 

12. Reason, J. R.: An Investigation of Some Factors 

Contributing to Individual Variation in Motion Sickness Susceptibility. FPRC Rept. 1277. Ministry of 

Defense, Flying Personnel Research Committee, 

London, 1968. 
NYSTAGMUS, TURNING SENSATIONS, AND ILLUSORY MOVEMENT 

IN MOTION SICKNESS SUSCEPTIBILITY 

J. Michael Lentz, Ph.D. 

I. Introduction. 

Some previous investigators18 20 23 have reported 

that vestibular sensitivity, as manifested by 

nystagmic eye movements, is of greater magnitude in motion sickness-susceptible individuals 

than in nonsusceptible individuals. However, 

there also have been reports of no differences in 

nystagmic output between susceptible and nonsusceptible individuals,21 and at least one contrasting report2 indicated that nonsusceptibles 

had more intense nystagmus. 

Investigations concerning rotation-induced sensations of turning have been equally inconclusive.19 Several early reports1 9 15 23 26 and at least 

one recent report24 indicated that susceptibles 

had longer durations of turning sensations or 

steeper sensation cupulograms than did nonsusceptibles. However, other experiments have not 

substantiated these reports; for example, in one 

study Dobie10 found that sensation cupulograms 

were significantly less steep for susceptible student pilots than for nonsusceptible student pilots, 

although in later, more extensive studies11 he 

concluded that sensation cupulograms were not 

significantly different for susceptible and nonsusceptible individuals. The later finding was 

supported by Clark and Stewart,5 who reported 

that thresholds for the perception of rotation 

were not correlated with motion sickness susceptibility. 

Although it is logically appealing to speculate 

that motion sickness-susceptible individuals 

have more sensitive vestibular systems, the conflicting reports do not provide unequivocal support for this position. It should be pointed out 

that sensitivity differences are not necessary to 

explain differential susceptibility to motion sickness. For instance, Graybiel's mode}13 14 of the 

structural elements of motion sickness does not 

necessarily suggest that susceptible and nonsusceptible individuals will differ in their nystagmic 

11 

or subjective turning responses. The basic proposition of his theory is that two separate response systems are activated by vestibular stimulation. The first, or V I, response system is 

characterized by nystagmic eye movements sen- . ' sabons of turning, oculogyral illusions, dizziness, 

and ataxia. The second, or V II, response system is manifested by the classic components of 

motion sickness: sweating, pallor, nausea, and 

vomiting. The factor that determines whether 

a VI response will activate the VII system is 

obtusely termed the "facultative linkage." Graybiel's theory implies that the individual who has 

a strong facultative linkage is more susceptible 

to motion sickness than is an individual who has 

a weak facultative linkage. Although the precise nature of this facultative linkage is not 

described, it may involve a neurophysiological 

mechanism or some other general nervous system 

phenomenon. The crux of the Graybiel theory 

is that primary vestibular responses (VI) are 

mediated by a system separate from that which 

mediates motion sickness (VII). Thus, individuals differing in their susceptibility to motion 

sickness would not necessarily be expected to 

differ in their primary vestibular responses. 

Some of the conflicting reports of nystagmus 

differences between susceptibles and nonsusceptibles may have been the result of several experimental deficiences related to a restricted range 

of subject samples, inadequate control of subjective alertness, or factors associated with previous 

laboratory experience and habituation processes. 

In this study, susceptible and nonsusceptible 

subjects were chosen from a laboratory-naive 

general population (students) so that the subject 

samples were not biased by a self-exclusion 

process (such as might exist in a pilot-candidate 

population) and were not comparisons of individuals who were laboratory naive with those 

who were laboratory experienced. 
Since it is well known that nystagmic responses 

can be enhanced by increasing the subject's alertness level and, conversely, can be greatly dimished by decreasing his alertness level,6 22 one 

of the specific goals of the present study was 

to determine how alertness levels, as defined by 

mental arithmetic and reverie instructions, affect 

the expression of nystagmus in motion sicknesssusceptible and nonsusceptible individuals; another goal was to carefully assess motion sensations. Of secondary interest was Reason's 

report24 that individuals having long spiral aftereffect (SAE) durations (i.e., long durations of 

apparent motion of a stationary spiral subsequent to viewing it while it was turning) had 

high scores on a motion sickness questionnaire 

(MSQ) and, conversely, low SAE scores were 

associated with low MSQ scores. Although it 

is tempting to conclude that motion sickness 

susceptibles have longer SAE durations than do 

nonsusceptibles, this conclusion may be unjustified because Reason's subjects were selected on 

the basis of extreme SAE scores and not on the 

basis of MSQ scores. Since the present study 

was particularly concerned with delineating individuals in the extremes of motion sickness susceptibility, it was on this basis (MSQ scores) 

that subject groups were selected and SAE durations compared. 

II. Method. 

A. Subjects. Forty-eight college students 

ranging in age from 18 to 39 yr served as subjects. Only one subject was older than 30, and 

the mean age of the group was 22.0 yr. The 

subjects were separated into four groups (N = 12 

subjects per group) on the basis of sex and susceptibility to motion sickness (susceptible men, 

susceptible women, nonsusceptible men, nonsusceptible women). Susceptibility to motion sickness was determined by scores on a biographical 

motion sickness history questionnaire administered to a larger group of students. 

Our motion sickness questionnaire was a modified version of one used by Birren3 and was 

scored on the basis of responses to questions concerning the individual's tendency to develop 

motion sickness in a variety of situations (e.g., 

while riding in automobiles, trains, or roller 

coasters) . The MSQ was administered to a large 

group of students; and only individuals who had 

12 

extreme scores were considered for inclusion in 

the experimental groups. Twenty-two percent 

of the total population tested (N =2,426) indicated that they had never been motion sick on 

any of the 20 items included in the MSQ; all 

"nonsusceptible" subjects were drawn from this 

group. "Susceptible" subjects were drawn from 

the other extreme; viz, from among the 9 · percent having the highest questionnaire scores in 

the total population tested. 

Subjects reporting a history of inner-ear problems, deafness, oculomotor disturbances, or head 

injuries that resulted in prolonged unconsciousness were eliminated from the study. All subjects were paid volunteers who agreed to remain 

free of drugs for at least 48 h prior to the testing period (this did not include birth control 

medications used by some of the female subjects) . 

Female subjects were tested between days 6 and 

20 of their menstrual cycle to avoid possible confounding effects of menstrual and premenstrual 

symptoms. 

B. Rotation Trials. All rotatory stimuli were 

delivered via an enclosed Stille-Werner RS-3 

rotation device located in a lightproof room. 

Each subject sat above the center of rotation 

in a small simulated cockpit fitted with two head 

restraints. One restraint held the subject's head 

in a normal, relatively upright position, placing 

the lateral semicircular canals approximately in 

the plane of rotation. The other head restraint 

was designed so the subject looked down 90° 

(1.57 rad) and to his left 45° (0.78 rad), thereby 

placing a pair of vertical semicircular canals 

approximately in the plane of rotation. In addition, the subject held a microswitch for signaling the start of turning, each perceived 90° turn, 

and the cessation of turning sensations. 

Each subject was tested during a single session that consisted of 12 rotation trials with intertrial rest intervals of 2 min each. All trials 

were conducted in total darkness and involved 

rotation in a clockwise direction. Each oddnumbered trial was an 18-s acceleation at 5° /s2 

(0.09 rad/s2 ) followed by rotation at a constant 

velocity of 90°/s (1.57 rad/s). During each of 

the acceleration trials, the subject estimated his 

turning velocity in a manner similar to that described by von Bekesy27 and by Groen and 

JongkeesY Each even-numbered trial consisted 

of a deceleration at 5° /s2 and resulted in the 
cockpit's becoming stationary. During the deceleration trials, the subject, according to instructions, either performed a mental arithmetic problem or assumed a reverie state. In trials 1 

through 8, the rotatory stimulation was applied 

to the lateral semicircular canals (the first :four 

trials were used to :familiarize the subjects with 

apparatus and procedures; these trials were not 

scored) ; in trials g through 12, the rotatory 

stimulation was applied to the vertical semicircular canals. 

C. Recording. Electrodes were taped to the 

outer canthus o:f each eye to record horizontal 

eye movements. Vertical eye movements were 

recorded :from a pair o:f electrodes positioned 

above the left eyebrow and below the eye on the 

malar surface. A .ground electrode was placed 

near the center o:f the :forehead. The corneoretinal 

potentials were amplified and recorded by an 

Offner type T electroencephalograph using a 3-s 

time constant. 

Eye movements were calibrated by means o:f 

lights mounted on the :front o:f the cockpit and 

subtending a visual angle o:f 15° (0.26 rad). 

Both horizontal and vertical eye calibrations were 

taken periodically during the testing sequence. 

D. Scoring. Horizontal nystagmus was scored 

with respect to total duration, number o:f nystagmic beats, and slow-phase displacement (degrees o:f eye movement). The duration o:f 

nystagmus was the time in seconds :from the 

start o:f the stimulus to the last nystagmic beat. 

The number o:f nystagmic beats was the total 

number o:f beats (:fast phases) that occurred during a given trial. Slow-phase displacement was 

the total extent to which the eyes deflected in 

a given direction during primary nystagmus. 

Eye movement calibrations allowed slow-phase 

eye displacement to be quantified in degrees. In 

all instances, the scorer was not informed o:f the 

subject category or stimulus condition. 

Vertical nystagmus during acceleration trials 

was scored in the same manner as was horizontal 

nystagmus. Vertical nystagmus during deceleration trials was often o:f poor quality8 12 16 17 and, 

as a result, was scored by an output rating technique that yielded scores o:f 0 (no nystagmus) 

to 4 (vigorous nystagmus) . The rating was conducted by an experienced nystagmus rater under 

a strict double-blind procedure wherein the rater 

was unware o:f subject category or stimulus condition. 

13 

Sensations o:f turning were measured with respect to duration and the number o:f reported 

goo turns. Duration was the time in seconds 

:from the initiation o:f physical turning to the 

signal representing the end o:f subjective turnmg. The number o:f goo turns was the total 

number o:f subjective signals minus two (start 

and stop signals) . 

E. Spiral Aftereffect. The stimulus was a 

black, three-throw, arithmetic spiral imposed on 

a white disc 20.32 em in diameter. The disc was 

positioned at a distance o:f 1.52 m :from the seated 

subject and was operated at a speed o:f 100 r/min. 

Each subject was instructed to maintain visual 

fixation on the center o:f the spiral disc and to 

estimate the persistence time o:f the SAE :following randomized induction periods o:f 15, 30, 60, 

and 110 s. There were three practice trials, each 

having an induction period o:f 30 s. The test 

trials consisted o:f three repetitions o:f each induction period; the order o:f presentation was 

randomized :for each subject. 

III. Results. 

A. Nystagrri/U8. 

1. Subjective turning condition. Table 1 presents the mean nystagmus measures obtained 

:from stimulation o:f the horizontal and vertical 

semicircular canals during those trials in which 

subjects signaled their turning sensations. Based 

on the 0.05 level o:f significance, separate analyses 

o:f variance revealed no significant sex nor susceptibility main effects or interactions :for any 

o:f the nystagmus measures (slow phase, number 

o:f beats, and duration). 

2. Mental arithmetic and reverie conditions. 

Nystagmus measures obtained :from stimulation 

o:f the horizontal semicircular canals during the 

reverie and the mental arithmetic conditions are 

presented in Table 2. There were no overall 

differences between susceptibles and nonsusceptibles :for either condition. However, the mental 

arithmetic condition was associated with significantly greater magnitude o:f slow-phase nystagmus (F (1, 44) =130.75, p<.001) and nystagmus 

duration (F (1,44) =38.72, p<.001) when compared to the reverie condition. Thus, changing 

the subject's instruction set significantly changed 

both slow-phase nystagmus and nystagmus duration. In addition to the significant main effect, 

there were significant interactions o:f sex w sus-
TAIIL£ 1. Mean Nysta~ Meuures. During Trials in. Ihlen fuming Sensations Were Recorded 

Motion Sickness Susceptibles Motion Sickness Nonswceptlbles c:ro. Means by Sex 

. Nystagllus Nuliber of NystagiiUS Nysta~ Nullber of Nystagllus Nystag~US Nullber of Nystagllus 

Slow Phase Nystaglllic Duration Slow Phase Nystaglllic Duration Sl~~~r Phase Nystaglaic Duration 

(Degrees) Beats (Seconds) (Degrees) Beats (Seconds) (Degrees) Beats (Seconds) 

c: lten 774 ., 49 .,. ... 0 95 52 7~ 87 50 :! ... ;: g~.= 

.:::~i Wol!len 1013 85 53 ~7 77 53 930 81 53 

.. ... Means 8~ 82 51 821 86 52 ! ~ 

... 6 Hen ~5 35 28 393 29 24 369 32 26 s ... ;: .... 

.. li ... WoMn 'K2 n 28 437 37 27 lKO 35 27 tu i > ... 

., 

.. Means 393 ~ 28 415 33 25 

TABLE z. Mean Nysta~ Measures for Horizontal Canal Sti.ulation 

During Reverie and Mental Arithmetic Conditions 

Reverie or Low-Alertness Mental Arith~~etic or High-Alertness 

Condition 

NystagnJS NUIIOer of 

Slow Phase Nystagndc 

N (Degrees) Beats 

Susceptible Hen 12 570 76 

Susceptible W0111en 12 660 78 

Nonsusceptible Hen 12 495 86 

Nonsusceptible W0111en 12 666 85 

All Hen 24 532 81 

All W0111e11 2lf 663 81 

All Susceptibles 24 615 77 

All Nonsusceptibles 24 580 86 

ceptibility w instructions for slow-phase nystagmus (F (1, 44) =7.31, p<.05) and nystagmus 

duration (F (1, 44) =5.99, p<.05). 

It should be noted that a simple effects comparison indicated that in the mental arithmetic 

condition, susceptible men had significantly less 

slow-phase nystagmus than did nonsusceptible 

men. This particular finding might be interpreted as suggesting the existence of a sex-linked 

trait expressed only in an alert or activated state. 

But this possibility seems minimal because dif14 

Condition 

Nystagmus Nystagmus Nl.lllber of Nystagmus 

Duration Slow Phase Nystagndc Duration 

(Seconds) (Degrees) Beats (Seconds) 

45 773 74 49 

46 1054 79 55 

45 964 103 61 

47 996 78 54 

45 868 89 55 

46 1025 78 54 

46 913 76 52 

41: 980 90 57 

ferences were not obtained between the same two 

groups in the subjective turning trials (Table 

1), which also involved heightened alertness. 

The significant three-way interactions for 

slow-phase nystagmus and nystagmus duration 

were largely the result of the unusually low 

scores of two individuals in the susceptible male 

group. Data from the female groups indicated 

that motion sickness susceptibility was not consistently associated with either slow-phase or 

duration scores. 
During vertical semicircular-canal stimulation, 

the reverie and mental arithmetic conditions produced nystagmus scores (ratings, in this case; 

Table 3) that yieldea no statistical difference 

based on susceptibility to motion sickness but 

did yield a significant main effect for instructional conditions (F (1, 43) =4.89, p<.05). 

Again, there was more nystagmus in the mental 

arithmetic condition than in the reverie condition. There was also a significant main effect 

of sex (F (1, 43) =5.81, p<.05) in that women 

had a higher vertical nystagmus rating. Although women consistently had more slow-phase 

nystagmus in all conditions (Tables 1, 2, and 

3), the only measures that evidenced a statistically significant difference between men and 

women were these vertical nystagmus ratings. 

There was a significant sex m instructions interaction for the vertical nystagmus rating; a 

simple effects test indicated that the nystagmus 

rating for women was significantly lower in the 

reverie condition than in the mental arithmetic 

condition (F (1, 43) =9.28, p<.Ol), whereas the 

ratings for men did not significantly differ between the instructional conditions. The difference in nystagmus ratings between men and 

women was not significant for the reverie condition but was significant for the mental arithmetic condition (F (1, 43) =10.06, p<.01). It 

should be pointed out that the nystagmus rating 

for men decreased slightly from the reverie condition to the mental arithmetic condition. The 

decrease may be attributed (i) to two nonsusceptibible men who had large rating differences 

across the reverie to the mental arithmetic condition (Table 3) and (ii) possibly to the coarseness of the rating categories and the difficulty 

inherent in rating vertical nystagmus. The differences obtained here between the duratio~s of 

vertical canal and of horizontal canal responses 

are consistent with differences in the time constant for those two sets of canals as reported in 

a number of other studies. 

TABLE 3. Mean NystagnRJS Ratings for Vertical Canal 

Stimulation During Reverie and Mental Arithmetic 

Conditions 

;Reverie or Mental Arithmetic 

Low-Alertness or High-Alertness 

N Condition Condition 

Susceptible Hen 12 1.04 1.25 

Susceptible Women 11* 1.50 2.18 

Nonsusceptible Hen 12 1.58 1.36 

Nonsusceptible Women 12 1.73 2.13 

All Hen 24 1.31 1.30 

All Women '23* 1.80 2.15 

All Susceptibles 23* 1.26 1.70 

All Nonsusceptibles 24 1.66 1.74 

*One record was not scoreable. 

15 
TABLE 4. Mean SlJ)jectlve Turning Measures 

Duration of Turning 

Sensations (Seconds) 

The NUib&r of Reported 

90 Tums 

Horizontal 

Canal 

N Stimulation 

Susceptible Men 12 32 

Susceptible Women 12 35 

Nonsusceptible Hen 12 36 

Nonsusceptible Women 12 29 

All Hen 24 34 

All Women 24 32 

All Susceptible:s 24 33 

All Nonsusceptibles 24 33 

B. Sensations of Turning. The mean scores 

£or the total duration o£ turning and the number 

o£ reported goo turns are presented in Table 4. 

Based on the 0.05 level o£ significance, separatB 

analyses o£ variance revealed no significant sex 

or susceptibility effects £or both measures. However, horizontal semicircular-canal stimulation 

elicited much stronger sensations than did vertical semicircular-canal stimulation £or both the 

duration o£ sensation (F (1, 44) =126.56, p< 

.001) and the number o£ goo turns reported 

(F (1, 44) =101.56, p<.001). These results are 

probably attributable to differences in the response characteristics o£ the two sets o£ canals, 7 12 

but the £act that horizontal canal stimulation 

always preceded that o£ the vertical canals must 

be considered. In addition, there was a significant sex x susceptibility interaction (F (1, 44) = 

7.42, p<.01) £or the duration measures. 

C. Spiral Aftereffect. The average durations 

o£ the sprial aftereffect illusion £or the £our induction periods are presented in Table 5. Nonsusceptible individuals had significantly shorter 

SAE durations than did susceptibles (F (1, 44) = 

5.62, p < .01). There was a significant main effect 

across induction periods (F (3, 132) =63.6g, 

16 

Vert leal Horizontal Vertical 

Canal Canal Canal 

Stimulation Stimulation Stillllll.ation 

24 19 14 

26 21 15 

27 23 16 

24 17 12 

26 21 15 

2~ 19 14 

25 20 15 

26 20 14 

p < .001) in that longer induction periods produced longer SAE durations. In addition, there 

was a significant susceptibility x induction-period 

interaction (F (3, 132) =4.82, p<.01). The 

significant interaction indicates that the motion 

sickness-susceptible individuals had a greater 

absolute increase in reported ~AE durations as 

a function o£ increasing SAE induction periods 

than did nonsusceptibles. This result suggests 

that longer induction periods would have greater 

reliability i£ SAE durations were used to predict motion sickness susceptibility. 

TABLE 5. llean Spiral Aftereffect (SAE) Duration (Seoonds) 

SAE Induction Period (Seconds) 

15 30 60 110 Total 

Susceptible Men 12 12.9 16.9 21.5 25.5 76.8 

Susceptible Wo.en 12 10.5 14.4 17.5 22.9 65.3 

Nonsusceptible Men 12 6.0 8.6 10.3 11.9 36.8 

Homsusceptible Wat~~en 12 7.~ 9.4 12.5 15.6 "·9 All lien 24 9.5 12.8 15.9 18.7 56.9 

All Wo.-en 24 9.0 11.9 15.0 19.2 55.1 

All Susceptlbles 24 11.7 15.7 19.5 24.2 71.1 

All Nonsusceptibles 24 6. 7 9.0 11.4 13.8 ~.9 
IV. Discussion. 

. The. primary emphasis of this study was to 

mvesbgate the relationship of motion sickness 

susceptibility to both nystagmic eye movements 

and turning sensations elicited by vestibular stim-

~latio~. Contrary to data reported by other 

1nvesbgators,'8 20 23 the results of the present 

~tudy indic~te that motion sickness susceptibility 

Is. ~ot consistently reflected in the magnitude of 

ehc1ted nystagmus and, clearly, there is no enhancement of nystagmus in susceptible individuals. 

It is apparent from the present results, as well 

as from other reports,4 6 that an increased alertness level of the subject has an enhancing influence on elicited nystagmus. Uncontrolled 

alertness levels could account for some of the 

reports indicating that individuals susceptible to 

motion sickness have more nystagmus than do 

nonsusceptibles. For example, it is possible that 

nonsusceptible individuals being tested over several trials in a dark environment could have 

become bored and drowsy and thus experienced 

a consequent loss of alertness; such a condition 

would tend to produce nystagmus of relatively 

low intensity. Conversely, susceptible individuals 

in the same situation may have maintained alertness because of the unpleasant and perhaps 

threatening vestibular stimuli. The current data 

indicate that instructional procedures to control 

alertness fluctuations are particularly important 

when a decrease in alertness level across trials 

may be mistaken for decreased vestibular sensitivity or response habituation. 

Motion sickness susceptibility was not reflected 

in the intensity or duration of turninO' sensa- • b 

bons among subjects tested in this study. That 

some of the previous reports concernin 0' turn- • • b 

mg sensatwns were in conflict may have been 

due to characteristics of the cupulometric technique employed. In comparison to most of the 

older studies, the current procedure used an 

acceleration of lower magnitude and lonO'er dura- • b 

bon, thereby allowing more time for central 

nervous system ( CNS) processes to influence 

after-responses. The procedure should have been 

advantageous for discriminating among people 

with differentially developed adaptive or suppressive mechanisms. 

The secondary emphasis of this study was to 

investigate the relationship between motion sick17 

ness susceptibility and persistence of the spiral 

aftereffect. The results indicated that motion 

sickness susceptibiles had longer SAE durations 

than did their counterpart nonsusceptibles; however, there was a large overlap in the range of 

scores. When considering individual SAE scores, 

susceptibility was best differentiated in the group 

of women. Thus, while there appears to be a 

relationship between motion sickness susceptibility and spiral aftereffect duration, the magnitude of this relationship is not such that highly 

reliable predictions of motion sickness susceptibility can be made on the basis of SAE values. 

In differentiating motion-sickness-susceptible and 

nonsusceptible individuals, the current SAE results are in agreement with those reported by 

Reason. 24 However, the current results tend 

not to support the Reason and Benson report25 

of a significant correlation between visual and 

labyrinthine aftersensations. If susceptibility 

can be differentiated by aftereffect characteristics in several sensory modalities as suggested 

by Reason and Benson,25 then both motion sickness susceptibility and the aftereffect phenomenon are probably associated with a general CNS 

mechanism (i.e., inhibition), which could be important from a theoretical basis. Future studies 

should be directed toward further clarification 

of the relationship between susceptibility to motion sickness and characteristics of responses to 

the SAE and other aftereffect illusions. 

There were no significant overall sex differences for nystagmus, sensations of turning, or 

SAE durations; however, there was a tendency 

for women to have more slow-phase nystagmus. 

This tendency, quite consistent but subtle in 

nature, suggests that further exploration of potential sex differences in nystagmic responses may 

be warranted. 

From a theoretical approach, the lack of 

overall differences between motion sickness-susceptible and nonsu~~eptible individuals in nystagmus and sensations of turning clearly refutes 

the classical theory that these responses are 

enhanced in susceptible individuals. Moreover, 

since indivdiual differences in motion sickness 

susceptibility are not correlated with nystagmie 

responses or sensations of turning, it is suggested that approaches that use these responses 

to assess the effectiveness of anti-motion-sickness 

drugs will have limited validity. 
The spiral aftereffect results suggest that 

motion sickness susceptibility may be related to 

some general CNS phenomenon that may be 

synonymous with the facultative linkage mechanism proposed by GraybieU3 14 The results are 

consistent with the implication from the Graybiel model that nystagmus and sensations of turning (V I responses) are not necessarily directly 

related to the classic symptoms of motion sickness (V II responses). It is speculated that a 

general nervous system process, such as inhibition, may be differentially developed in individuals and may be overtly expressed in spiral 

aftereffect durations, motion sickness susceptibility, and, perhaps, a variety of other measures 

but not in the primary measures of vestibular 

responses-nystagmus and turning sensations. 

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18 

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12. Gilson, R. D., C. W. Stockwell, and F. E. Guedry, Jr_: 

Nystagmus Responses During Triangular Waveforms 

of Angular Velocity About the Y- and Z-axes, ACTA 

OTO-LARYNGOLOGICA, 75:21-26, 1973. 

13. Graybiel, A. : Structural Elements in the Concept 

of Motion SicknE>ss, AEROSPACE MEDICINE, 40: 

351-367, 1969. 

14. Graybiel, A.: Vestibular Mechanisms Underlying 

Certain Problems in a Rotating Spacecraft. In 

A. Graybiel (Ed.), Fifth Symposium on the Role of 

the Vestibular Organs in Space Exploration, U.S. 

Government Printing Office, Washington, D.C., 1970, 

pp. 35-39. 

15. Groen, J. J., and L. B. W. Jongkees: Turning Test 

With Small Regulable Stimuli. IV. The Cupulogram 

ObtainE>d by Subjective Angle Estimation, JOURNAL 

OF LARYNGOLOGY AND OTOLOGY, 62:236-240, 

1948. 

16. Guedry, F. E., Jr., and A. J. Benson: Nystagmus 

and Visual Performance During Sinusoidal Stimulation of the Vertical Semicircular Canals. U.S. 

Naval Aerospace Medical Research Laboratory Report No. 1131, 1971. 

17. Hixson, W. C., and J. I. Niven : Directional Differences in Visual Acuity During Vertical Nystagmus. 

U.S. Naval Aerospace Medical Institute Report No. 

1079, 1969. 

18. Kennedy, R. S., and A. Graybiel: Validity of Tests 

of Canal Sickness in Predicting SuscE>ptibility to 

Airsickness and Seasickness, AEROSPACE MEDICIN1iJ, 33 :935--938, 1962. 

19. Lansberg, M. P. : A Primer of Space Medicine. Amsterdam, Elsevier, 1960. 

20. Lidvall, H. F. : Mechanisms of Motion SicknE>ss as 

Reflected in the Vertigo and Nystagmus Responses 

to Repeated Caloric Stimuli, ACTA OTO-LARYNGOLOGICA, 55:527-536, 1962. 

21. McDonough, F. E., and M. W. Thorner: Regulation 

Barany and Swing Test in Navigation Cadets. Committee on Aviation Medicine Report No. 116, 1942. 

22. Mowrer, 0. H. : Influence of "Excitement" on the 

Duration of Post-Rotational Nystagmus, ARCHIVES 

OF OTOLARYNGOLOGY, 19 :46-54, 1934. 

23. Preber, L.: Vegetative Reactions in Caloric and 

Rotatory Tests, ACTA OTO-LARYNGOLOGICA 

(Supplement), 144:1-119, 1958. 

24. RE>ason, J. T.: An Investigation of Some Factors 

Contributing to Individual Variation in Motion SicknE>ss Susceptibility. Flying Personnel Research Committee Report No. FPRC/1277, 1968. 

25. Reason, J. T., and A. J. Benson: Individual Differences in the RE>ported Persistence of Visual and· 

Labyrinthine After-Sensations, and of Exponentially 

Decaying Visual and Auditory Signals, BRITISH 

JOURNAL OF PSYCHOLOGY, 59:167-172, 1968. 

26. Van Egmond, A. A. J., J. J. Groen, and G. de Wit: 

The Selection of Motion Sickness-Susceptible Individuals, INTERNATIONAL RECORD OF MEDICINE, 167:651--660, 1954. 

27. Von Bekesy, G.: Subjective CupulomE>try, ARCHIVES. 

OF OTOLARYNGOLOGY, 61 :16-28, 1959. 
SOME PSYCHOLOGICAL CORRELATES OF MOTION 

SICKNESS SUSCEPTIBILITY 

William E. Collins, Ph.D. 

J. Michael Lentz, Ph.D. 

I. Introduction. 

In earlier conceptions of what is currently 

known as motion sickness, individuals were considered to be of weak constitution and generally 

lacking in "moral fibre" if they manifested motion sickness symptoms. This viewpoint persisted in the literature through the late 1940's 

despite chronic motion sickness in individuals 

renowned for their courage, such as Julius 

Caesar, Lord Nelson, and Lawrence of Arabia.19 

During and following World War II, airsickness, 

one form of motion sickness, became a particular 

concern of the military and was often attributed 

primarily to psychic factors, such as tension, 

fear, anxiety, or nervousness. 5 9 10 1a 21 24 2s 29 33 

In addition to airsickness, some chronic seasickness among Navy personnel was reported to be 

strongly associated with neurotic traits and a 

tendency toward fainting as revealed during 

psychiatric examinations. 27 

In the years immediately following World 

vVar II, the only noteworthy attempt to associate 

psychological characteristics with susceptibility 

was made by Birren,t who reported a significant 

positive correlation ( r= 0.43) between scores on 

the Cornell Selectee Index (a neuropsychiatric 

inventory) and those on a motion sickness history questionnaire. Although Birren and his 

predecessors had noted that some psychological 

factors appeared to be related to motion sickness, studies conducted by Wendt31 were influential in causing this line of research to be almost 

abandoned for a decade. \V endt indicated that 

the primary cause of motion sickness was stimulation of the vestibular sensory apparatus and 

that "factors such as physiological state, posture, 

and wave-character are of far greater potency 

than psychological factors in their effects on motion sickness rates." 

19 

Zwerling35 took exception to Wendt's suggestion. In 1947, Zwerling34 had shown that the 

incidence of motion sickness in experimental subjects was significantly increased when they were 

exposed to electric shock during rotation trials; 

he concluded that fear or anxiety heightened susceptibility. He also noted a relationship ( statistically nonsignificant) between motion sickness 

susceptibility and neurotic tendencies indicated 

as defined by the Minnesota Multiphasic Personality Inventory (MMPI). In reply to Wendt, 

Zwerling indicated that sensory stimulation, 

psychosomatic factors, general physical fitness, 

type of motion, and secondary factors (e.g., temperature, ventilation) were all operative in the 

etiology of ·motion sickness and there was no 

basis for the selection of any one as the single 

cause of motion sickness. 

Naval cadets have been the subjects of many 

of the more recent studies of motion sickness 

susceptibility and personality characteristics. 

Harris12 reported that conventional analyses of 

Rorschach Test scores and MMPI profiles provided no replicable differences between airsick 

and nonairsick cadets; however, he concluded 

that there remained at least suggestive evidence 

of a greater disturbance in personality functioning among the airsick group. In a study of nine 

cadets, McMichael and Graybiel18 reported significant relationships between demonstrated motion sickness susceptibility and the Rorschachderived composite dimensions of "rigidity" and 

"lability." 

Using large samples (157-229) of naval flight 

students, Guedry and Ambler11 reported that 

neuroticism on anxiety scores (from the Eysenck 

Personality Inventory and the Omnibus Personality Inventory) "tended to correlate significantly" with motion sickness symptoms (produced by a laboratory motion device) as rated 
in the Brie£ Vestibular Disorientation Test 

(BVDT) ; they also noted a significant (unspecified) correlation between BVDT symptoms 

and the masculinity-femininity scale o:f the 

Omnibus Personality Inventory (the masculinity 

end o:f the scale related to low motion sickness 

sensitivity). Similarly, Reason and GraybieJ23 

have reported significant but small (about 0.20) 

correlations between the motion sickness history 

o:f 70 naval cadets and both the introversion and 

the neuroticism scales o:f the Eysenck Personality 

Inventory. A similar study by Wilding and 

Meddis32 :found that among a group o:f 60 students, motion sickness history was significantly 

correlated with Eysenck's neuroticism ( r = 0.46) 

but not with introversion (r=0.04). These results were, however, contrary to those obtained 

by Kottenhoff and Lindahl,13 who had tested 50 

volunteer subjects in the laboratory and reported 

a significant correlation ( 0.35) between introversion as measured by the Maudsley Personality 

Inventory (MPI) and demonstrated motion 

sickness symptoms. The MPI measure o:f neuroticism did not correlate significantly with the 

demonstrated symptoms, nor did either measure 

correlate significantly with a travel sickness questionnaire. Moreover, anxiety, as defined by the 

Taylor Manifest Anxiety Scale, showed no correlation with either the questionnaire or demonstrated symptoms. 

The many studies on the relationship o:f personality :factors to motion sickness susceptibility 

have varied considerably in their investigative 

approaches and perhaps even more divergently 

in their conclusions. A reason :for the divergent 

findings may pertain to the subject populations 

used. In the vast majority o:f studies, subjects 

have been prescreened military trainees; in a 

:few other studies, they have been relatively small 

groups o:f people unscreened :for susceptibility 

characteristics. The need :for a comparison o:f 

highly susceptible with nonsusceptible people 

was noted as early as 1949 by Tyler and Bard,30 

whose comments in this regard were more recently cited by Reason and Brand. 22 The intent 

o:f the present study was to conduct a comprehensive investigation o:f the relationship between 

motion sickness susceptibility and selected personality :factors by comparing subjects who report high susceptibility to motion sickness with 

subjects who report nonsusceptibiilty to any 

:form o:f motion sickness. 

20 

II. Method. 

A. Subjects. Four groups o:f 37 subjects each 

(susceptible men, susceptible women, nonsusceptible men, nonsusceptible women) were obtained 

:from a college student population ranging in 

age :from 18 to 39 years. Susceptibility to motion sickness was determined by scores on a modified version o:f the motion sickness questionnaire 

(MSQ) used by Birren.1 The MSQ was administered to a large group o:f university students 

(N=2,432), and only individuals with extreme 

scores were considered :for inclusion in the experimental groups.15 Twenty-two percent of the 

total population tested indicated that they had 

never been motion sick on any of the 20 items 

included in the MSQ (e.g., automobiles, trains, 

roller coasters, ships) ; all nonsusceptible subjects 

were drawn from this extreme. Susceptible subjects were drawn from the other extreme; viz, 

from among the 9 percent with the highest questionnaire scores in the total population tested. 

·within the susceptible and nonsusceptible categories, the experimental subjects were chosen at 

random. 

B. Procedure. Each subject was tested on at 

least three but not more than six of the eight 

tests in Table 1 (the total number for each test 

is indicated in the table). The tests were administered in accordance with directions in respective 

test manuals or in published references with one 

exception: subtests in the Floor Ataxia Test 

Battery were presented in a modified order. 

1. The Floor Ataxia Test Battery7 is reported 

to be an indicator of the loss or impairment of 

vestibular function. The battery consists o:f five 

subtests that measure equilibrium while standing 

or walking without the aid of vision. The tests 

and their order of presentation were: Stand on 

One Leg-Eyes Closed (SOLEC: both le:ft and 

right legs), Sharpened Romberg ( SR: standing 

heel to toe), vValk on Floor-Eyes Closed 

(WOFEC), and Walk a Line-Eyes Closed 

(WALEC). 

2. The State-Trait Anxiety Inventory (STAI) 

developed by Spielberger and his associates28 

assesses anxiety characteristics. The first portion of the STAI measures the individual's 

"state" anxiety, an expression of the individual's 

ongoing or current anxiety level, which can 

fluctuate considerably with changes in environmental situations. The second portion of the 
TABLE 1. Number and Category of Subjects Administered 

Each of the Eight Tests 

Tests 

Floor Ataxia Test Battery 

Cornell Medical Index 

Cornell Word Form 

Eysenck Personality Inventory 

Rotter Internal-External Control Scale 

16 PF (Form A) 

State-Trait Anxiety Inventory 

Menstrual Distress Questionnaire 

STAI measures the individual's predisposition 

("trait") towards anxiety. Trait anxeity is considered a relatively stable behavioral characteristic or pattern indicative of the individual's 

general response to anxiety-producing events. 

The STAI comprises 40 statements that people 

use to describe themselves. The first 20 statements describe the individual as he :feels right 

now, and the last 20 statements, as he generally 

:feels. For instance, to the statement "I :feel 

calm" the individual has the choice o:f the following replies: not at all, somewhat, moderately 

so, or very much so. All subjects who completed 

the STAI were also used as 'subjects in another 

experiment involving whole-body rotation. 14 Following the rotation experiment, the subjects 

again completed the "state" portion of the STAI, 

and, therefore, both prerotation and postrotation state anxiety scores were obtained. 

3. The Menstrual Distress Questionnaire 

(Form A) was constructed to determine the extent to which women experienced common menstrual symptoms."0 The questionnaire asks a 

respondent to rate her degree of menstrual-related distress for 47 symptoms during three 

phases of her most recent menstrual cycle (menstrual flow, 1 week be:fore menstrual flow, reSusceptibles Nonsusceptibles 

Men Women Men Women Total 

37 37 37 37 148 

37 37 37 37 148 

25 25 25 25 100 

25 25 25 25 100 

25 25 25 25 100 

25 25 25 25 100 

12 12 12 12 48 

12 12 24 

mainder of cycle). The distress rating is a 

6-point scale ranging from no experience of the 

symptom to an acute or partially disabling 

expenence. 

21 

4. The Cornell Medical Index (CMI) is a 

health questionnaire designed to collect general 

medical and psychiatric data to :facilitate patient 

examination. 2 The CMI is composed o:f 195 questions concerning a wide variety o:f medical and 

emotional problems that may have occurred in 

an individual's past; a "yes" or "no" answer is 

required to each item. 

5. The Cornell Word Form (CWF-2) was 

designed to screen for potentially serious neuropsychiatric and psychosomatic disturbances. 

It consists o:f 80 single-word items to which the 

respondent associates one of two alternate descriptions. 

6. The Eysenck Personality Inventory (EPI) 

measures personality in terms o:f two dimensions, extraversion-introversion and neuroticismstability ;6 a Lie Scale is included. The EPI was 

developed from the earlier Maudsley Personality 

Inventory (MPI) and correlates highly with it. 

The test presents 57 questions relating to how 

the respondent may behave, feel, and act; each 

question requires a "yes" or "no" answer. 
TABLE 2. Mean Scorea for the Floor Ataxia Teat Battery, the State-Trait Anxiety Inventory, the Cornell tl!dical 

Index (CHI), ~he Cornell Word Pont (QU), the Eyaenck Peraonality Inventory (Extraveraioo, 

Neurotici••• and Lie Scalea) 1 and the Iotter Internal-External (I-E) Control Scale 

Floor Ataxia Teat latte!I State-Trait .Anxietz. Invento!l Cornell Teata Ez.aenck !ill!!: 

State (Before State (After I-E 

SOLEc-R SOLEC-L SR WOFEC WALEC Trait 

Su.ceptible Men 89.6 86.4 208.8 26.1 35.9 37.5 

Suaceptible Wo.en 75.1 68.3 196.8 25.2 44.9 35.7 

Noa.auaceptible 

lien 79.1 89.6 212.7 28.0 28.0 30.1 

Noaauaceptible 

Wo•n 57.0 61.2 180.2 23.5 49.1 30.6 

All lien 84.4 88.0 210.7 27.1 31.9 33.8 

All Wo.en 66.0 64.7 188.5 24.3 47.0 33.1 

All Suaceptiblea 82.4 77.3 202.8 25.6 40.4 36.6 

All Honauaceptiblea 68.0 75.4 196.4 25.8 38.6 30.3 

7. The Rotter Internal-External Locus of Control Scale25 was developed to assess the extent 

to which individuals believed that they could 

control or influence events that affect them. For 

each of 29 items the subject must select one of 

a pair of statements about how he/she is affected 

by societal events. 

8. The 16 Personality Factors (16 PF) test 

(Form A) is a multidimensional personality 

factor questionnaire established on the basis of 

Cattell's concept of the total human personality. 3 

The test consists of 187 items to which one of 

three alternative responses must be selected (e.g., 

Money cannot bring happiness: (a) true (b) in 

between (c) false.). Scores can be determined 

for 16 primary factors, 8 secondary factors, and 

4 criteria factors. The factors are described m 

detail elsewhere2 but may be summarized, in 

order, as follows: 

a. Primary factors : (A) reserved-outgoing; 

(B) dull-bright; (C) affected by feelingsemotionally stable; (E) humble-assertive; (F) 

sober--happy-go-lucky; (G) expedient--conscientious; (H) shy-venturesome; (I) tough 

minded-tenderminded; (L) trusting-suspicious; (M) practical-imaginative; (N) forthright-astute; (0) self-assured-apprehensive; 

(Q1 ) conservative-experimenting; (Q2 ) group 

dependent-self -sufficient; ( Q3 ) undisciplined 

self -conflict--controlled; ( Q4 ) relaxed-tense. 

b. Secondary factors: (1) extraversion-introversion; ( 2) low anxiety-high anxiety ; ( 3) 

sensitivity-tough poise; ( 4) dependence-independence; ( 5) discreetness; ( 6) prodigal subjectivity; ('7) fluid intelligence; ( 8) superego. 

22 

Rotation) Rotation) aa a.IP E • L Scale 

35.8 37.2 22.5 3. 7 12.1 8.9 2.8 9.6 

31.9 37.5 28.0 4.0 13.4 10.4 2.4 10.7 

31.3 28.5 10.7 1.8 15.4 6.6 2.3 9.2 

32.9 32.3 17.0 1.8 13.2 7.3 2.6 11.1 

33.6 32.8 16.6 2.8 13.8 7.8 2.6 9.4 

32.4 34.9 22.5 2.9 13.3 8.8 2.5 10.9 

33.9 37.3 25.3 3.9 12.7 9.6 2.6 10.1 

32.1 30.4 13.9 1.8 14.3 7.0 2.5 10.2 

c. Criterion factors: ( 1) neuroticism; ( 2) leadership; (3) creativity; (4) school achievement. 

III. Results. 

Group means for all tests except the Menstrual 

Distress Questionnaire and the 16 PF are presented in Table 2. With the same exceptions, all 

data were evaluated by using a two-way analysis 

of variance; the respective F-values are presented 

in Table 3 with p < .05 the accepted level for 

significance. 

TABLE 3. Results of Analyses of Variance of Teat Scores 

(F Ratios) 

Sex • Suscepti- SuaceptiTeat s .. bility bility 

Ataxia Ba tterl 

SOLEC-R 6.22 * 3.82 0.27 

SOLEC-L 9.37 ** 0.06 0.46 

SR 4. 76 * 0.39 1.02 

WOYEC 8.00 ** 0.03 3.52 

WALEC 9.21 ** o.u 1.48 

m! 

Trait 0.14 8.14 ** 0.24 

State (Before 

Rotation) 0.44 0.99 2.44 

State (After 

Rotation) o.u 9.18 ** 0.59 

~ 

CIII 4.88 * 18.14 *** 0.02 

CWP 0.06 12.89 *** 0.15 

IYaenck 

EPI-E o.so 4.99 • 6.05. 

EPI-N 1.97 12.11 *** 0.33 

EPI-L 0.04 0.22 1.58 

.!:2!!!!. 3.23 0.00 0.17 

dF 

1,144 

1,144 

1,144 

1,144 

1,144 

1,44 

1,44 

1,44 

1,144 

1,96 

1,96 

1,96 

1,96 

1,96 

* R. < .OS ** R. < .01 *** 1!. < .001 
A. Floor Ataxia Test Battery. The results 

from each of the five equilibrium subtests indicated that men had significantly better balance 

scores than did women (p < .05-p < .01). This 

significant effect was attributable to the differences between nonsusceptible men and women; 

no differences between susceptible men and 

women were significant. There were no significant differences between susceptible and nonsusceptible groups nor were there significant 

sex x susceptibility interactions. 

B. State-Trait Anxiety Inventory. Susceptible individuals had significantly higher tmitanxiety scores than did nonsusceptibles (p < .01). 

This relationship indicates that two relatively 

permanent personality characteristics, trait anx--

iety and motion sickness susceptibility, are associated either directly or indirectly. The "state" 

portion of this inventory was administered both 

before and after rotatory vestibular stimulation.14 Prior to rotation, there were no significant state anxiety differences between groups; 

:following rotation, however, susceptible individuals had significantly higher state anxiety 

scores (p<.01). A three-way analysis o:f variance indicated that the state-anxiety level o:f 

susceptible individuals increased significantly 

(p<.001) :from the prerotation to postrotation 

sessions, whereas nonsusceptibles evidenced a 

slight but nonsignificant decrease in state anxiety. 

C. Menstrual Distress Questionnaire. 0:£ the 

47 symptoms possibly related to menstrual distress, :fatigue was the only symptom differentially 

expressed ; susceptible women reported more 

fatigue than did nonsusceptibles (p < .05 by t 

test). When the 47 symptoms were collated to 

the suggested eight general :factors, there were 

no significant differences between susceptible and 

nonsusceptible women. 

D. Oornell Medical Index. Susceptible individuals had significantly more "yes" answers on 

the Cornell Medical Index than did nonsusceptibles (p < .001). In addition, women had more 

"yes" answers than did men (p < .05). 

E. Oornell Word Form. Evaluation o:f Cornell Word Form scores indicated that motionsickness susceptible individuals had significantly 

higher scores than did nonsusceptibles (p < .001). 

There were no significant sex differences nor sex 

x susceptibility interactions. 

23 

F. Eysenck Personality Inventory. Nonsm;-

ceptible individuals had significantly higher 

scores on the Extraversion Scale o:f the Eysenck 

Personality Inventory than did motion sickness 

susceptibles (p < .05). In addition, there was 

a significant sex x susceptibility interaction 

(p < .05). On the Neuroticism Scale, susceptibles had significantly higher scores than did 

nonsusceptibles (p<.001). There were no significant differences on the Lie Scale. 

G. Rotter Internal-External Oontrol Scale. 

The Rotter Internal-External Control Scale 

did not significantly differentiate any o:f the 

groups in this study. 

H. 16 PF. All primary, secondary, and criterion scores :for groups represented in Figure 1 

:fall within one standard deviation o:f the mean 

established :for a college student population. 

However, within this relatively normal range o:f 

scores, there were numerous significant group 

differences. An analysis o:f Figure 1 :for significant susceptibility differences plus a departure 

:from mean scores yielded a description o:f our 

subject groups as indicated in Table 4. 

In general, nonsusceptibles tended to score as 

less neurotic, better adjusted, and more venturesome than susceptibles, and susceptibles in genTABLE 4. Descriptions of Groups Based on 16 PF Scores by Sex 

Group 

Male Nonsuaceptiblea 

Male Susceptiblea 

Feu.le Nonausceptiblea 

Fe-.le Suaceptiblea 

All Nonsusceptibles 

All Suscept ib les 

All Men 

All Women 

and Susceptibility Catesories 

Major Descriptors Baaed on 16 pp Scores 

emotionally stable; a .. ertive; happy-g~ 

lucky; venturesome; extraverted; thinking 

(va. emotionally) oriented; independent; 

less neurotic; good leader 

tendenninded; shrewd; dt.creet 

shrewd; self-assured; relaxed; adjusted 

(less anxious); discreet; leas neurotic; 

good leader 

tendernr~nded 

emotionally stable; venturesome; selfassured; relaxed; adjusted (less anxious); 

thinking (vs. emotionally) oriented; less 

neurotic; good leader 

tenderminded: subjective 

assertive; tough minded; experimenting; 

strong self-concept; thinking (vi. 

emotionally} oriented; independent; 

less neurotic; good leader; academic 

achievers 

tenderminded; shrewd; discreet; 1ubjective 
7.50 A. ALL MEN 

7.00 

6.50 

6.00 

5.50 

5.00 

4.50 

4.00 

* * * • * * * * • I 2 3 4 5 6 7 8 9 10 II 12 13 14 IS 16 

* * • • * 4 6 8 

* * 

- SUSCEPTIBLES 

--- NONSUSCEPTIBLES 

* * 4 

7.50 B. ALL WOMEN 

7.00 

6.50 

6.00 

5.50 

w 5.00 

lr 4.50 

0 4.00 u 

(f) • * 

z I 2 3 4 5 6 7 8 9 10 II 

\ 

\ 

* * * * * 12 13 14 15 16 4 6 

! /', 

~ 

/ '~ 

''--~ I 

I 

/ - SUSCEPTIBLE$ 

* * 

--- NONSUSCEPTIBLES 

* * 4 

w 7.50 C. ALL SUBJECTS 

1-

(f) 7.00 

6.50 

z 6.00 

<( 5.50 

w 

~ 5.00 

4.50 

4.00 

• * • * * * * * I 2 3 4 5 6 7 8 9 10 II 1_2 13 14 15 16 

* * * * 4 

* 6 

/',, 

~ 

I ' 

I 

I 

I 

/ - SUSCEPTIBLES 

J --- NONSUSCEPTIBLES 

* • • • 4 

7.50 D. ALL SUBJECTS 

7.00 

6.50 

6.00 

5.50 

5.00 

4.50 

4.00 

* A 8 C * E 

* * • FGHILMN 

I 2 3 4 5 6 7 8 9 10 II 12 13 14 15 16 

$ P< .05 

** P<.OI 

PRIMARY SCORES 

* * * * 

4 

* * * * 

SECONDARY SCORES 

8 

* * * * 

--- WOMEN 

* * 

4 

CRITERION SCORES 

FIGURE 1. Mean sten values for primary, secondary, and criterion scores on the 16 PF test. 

eral had factors in common with women (tenderminded, subjective). The 16 PF raw scores were 

converted by using established regression weights3 

to predict raw scores on the masculinity scale 

of the Guilford-Zimmerman Temperament Survey. N onsusceptible individuals had significantly higher scores (more mascline) than did 

susceptible individuals in both the male (p < .01) 

and female (p<.05) groups. 

24 

IV. Discussion. 

In this study, the Floor Ataxia Test Battery 

was the only test related in a classical or direct 

sense to vestibular functioning. Individuals 

who evidence dramatic differences in the manifestation of motion sickness might be expected 

to differ in their responses to the subtests in this 

battery because both motion sickness and the 

ataxia tests are directly dependent on vestibular 
functioning. Moreover, other investigators8 17 

have suggested that susceptible and nonsusceptible individuals may perform differently on 

equilibrium tests. Our data do not support this 

contention, although they do agree with previous 

reports indicating that men perform better than 

women on these tests. It should be noted that 

other direct manifestations of vestibular function, such as duration and magnitude of both 

nystagmus and turning sensations to angular 

stimulation, have also shown no relationship to 

motion sickness susceptibility.14 

Some significant relationships between motion 

sickness susceptibility and personality or psychological :£actors were obtained. The State-Trait 

Anxiety Inventory (STAI) measured both trait 

anxiety, a persistent personality characteristic, 

and state anxiety, a temporary characteristic 

prone to frequent fluctuations. Susceptible individuals had significantly higher trait-anxiety 

stores; they also had significantly higher stateanxiety scores following a period of exposure to 

rotation than did nonsusceptibles. Although the 

rotational stimuli used was a type that usually 

does not induce motion sickness, the :£act that 

most susceptible subjects were disturbed by it 

emphasized the high degree of susceptibility o:£ 

this particular group. Since prerotational stateanxiety scores did not differ, it is proposed that 

the vestibular stimulation produced by the rotatory device triggered the dormant anxiety predisposition (trait anxiety) in susceptible subjects 

as was evidenced by elevated postrotational stateanxiety scores and some feelings o:£ malaise. 

Although alertness and axiety may be separate neuropsychophysiological entities, they may 

work in a highly correlated fashion in individuals susceptible to motion sickness. For instance, the high trait-anxiety predisposition of 

susceptible individuals might be quickly expressed 

in stressful motion environments. The elevated 

anxiety level could, in turn, heighten subjective 

alertness, which has been shown to accentuate 

some vestibular responses. 4 This interrelated 

system could become self-perpetuating in motion 

environments because of the tendency o:£ increased 

vestibular activity to accentuate the development 

o:£ anxiety. 

The results from the Cornell Medical Index 

(CMI) indicated that susceptible individuals reported significantly more physical and emotional 

25 

difficulties than did nonsusceptibles. According 

to the CMI test manual, many individuals in 

the susceptible group would be suspected of having a medically significant disturbance. Moreover, a significant difference between susceptible 

and nonsusceptible individuals was also evidenced by scores on the Cornell Word Form. 

In this instance, nonsusceptible individuals had 

significantly :£ewer indications of potential neuropsychiatric or psychosomatic disturbances. Care 

should be exercised in interpreting this significant difference, however, because the susceptible 

subjects did not have abnormally high scores. 

The results :£rom the Eysenck Personality Inventory (EPI) indicated that nonsusceptible individuals were significantly more extraverted 

and less neurotic than susceptibles. Again, the 

scores did not suggest that susceptibles were abnormal in either respect. Although the EPI 

indicated that nonsusceptibles were more extraverted, this tendency was not expressed m 

scores on Rotter's Internal-External Locus of 

Control Scale. 

In summarizing scores on the 16 PF test, it 

can be generally concluded that nonsusceptible 

individuals tended to be scored as tough and 

aggresive. In some ways, these descriptors are 

suggestive of stereotypical male behavior; the 

results of other tests, on which nonsusceptibles 

scored significantly higher than susceptibles in 

masculinity ratings, support this general description. 

Moreover, a basic conclusion that may be 

drawn :£rom the 16 PF test as well as from most 

o:£ the other tests in this study is that nonsusceptible individuals may be better prepared to 

cope in a nonemotional manner with stressful 

situations, whereas susceptible individuals may 

be more likely to manifest emotional responses 

in the same situat:ons. In short, it appears that 

susceptibles are more likely to have an autonomic 

nervous system response to stress, be it a mental 

or a physical (e.g., vestibular) stressor. 

Results across the battery o:£ psychological 

tests used in this study seem quite consistent. 

That they show such consistency in significantly 

distinguishing susceptible :£rom nonsusceptible 

people probably reflects the selection factors used 

in defining the two groups. The vast majority 

of previous studies used aviation or naval cadets 

as subjects and defined susceptibility in operational terms; i.e., by those who became motion 
sick during training or in laboratory devices. 

Such groups, however, were likely to exclude 

highly susceptible people, were virtually all men, 

and would have already been screened in medical 

examinations for psychological and physical 

abnormalities. Moreover, a precipitating cause 

of sickness in these military studies could well 

have been situation-specifir· anxiety and the fear 

of failure in meeting occupational requirements; 5 

that is, fundamental factors that might underlie 

pervasive susceptibility to motion sickness might 

not be consistently manifested by those who 

demonstrate relatively situation-specific sickness 

or who suffer motion sickness only occasionally. 

One would expect that tests on less extreme 

groups than those used in this study would result in weaker and less consistent relationships 

between personality factors and motion sickness 

characteristics. 

As a final point, the personality characteristics 

that distinguish our highly susceptible and nonsusceptible subjects are not, of course, universally 

generalizable. Thus, not all anxious, introverted individuals are highly susceptible to motion sickness, and not all masculine, extraverted, 

calm individuals are nonsusceptible. 

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