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The effects of distance between interactants and subject anxiety on conjugate lateral eye movements
BRAIN
AND
COGNITION
4, 328-337 (1985)
The Effects of Distance between Interactants and Subject Anxiety on Conjugate Lateral Eye Movements RAND E LENHART V. A. Medical
Center,
Palo Alto,
California
and State
University
of New
York
at Buffalo
Ehrlichman and Weinberger (1978, Psychological Bulletin 85, 1080-l 101) have suggested that the distance between participants during face-to-face interviewing may be a significant determinant of directional patterns of conjugate lateral eye movements (CLEMS). As predicted, at the longer, social distance CLEMS were dependent on the verbal or spatial nature of questions; when interactants were at a closer, personal distance CLEMS became more consistent in direction, regardless of problem type. Distance manipulation also differentially altered CLEM patterns for the two sexes. 8 1985 Academic Press. IK.
Conjugate lateral eye movements (CLEMS), spontaneous reactive gaze shifts to the right or left during reflective thinking, are presumed to reflect contralateral cerebral hemispheric activation (Duke, 1968; Galin & Omstein, 1974; Gur, Gut-, & Harris, 1975; Kinsbourne, 1972). A consistent finding in CLEM research is that subjects tend to display a characteristic direction of averting the eyes so that each may be classified as a “right mover,” “left mover,” or “bidirectional” (Duke, 1968; Gur et al., 1975). Bakan (1969) attempted to explain this evidence for “individual hemisphericity,” that is, a tendency to rely most heavily on the processing mode of one hemisphere, in terms of relative dominance of one cerebral half over the other; CLEMS represent easier activation of the hemisphere contralateral to the direction of eye movement. Subsequent studies have revealed that individuals with similar CLEM patterns also have cognitive and personality profiles resembling one another (Dewitt & Aver-ill, 1976; Gur & Gur, 1975; Hiscock, 1977; Weiten & Etaugh, 1973). An alternative research strategy has focused on the effects of specific types of tasks upon the direction of CLEMS (Galin & Ornstein, 1974; Kinsbourne, 1972; Schwartz, Davidson, & Maer, 1975). The majority of these studies have shown spatial and emotional questions to evoke more Address requests for reprints to Rand E Lenhart, Ph.D., Psychology Service 116B, V. A. Medical Center, 3801 Miranda Ave., Palo Alto, CA 94304. 328 0278-2626185 $3.00 Copyright All rights
6 1985 by Academic Press, Inc. of reproduction in any form reserved.
CONJUGATE
LATERAL
EYE
MOVEMENTS
329
frequent left CLEMS, whereas verbal and numerical problems have produced more right-going gaze shifts. Analogous to the “hemisphericity” model, these results have been attributed to the differential activation of the two cerebral hemispheres as a consequence of the cognitive demands of differing problems. Recently, the Gurs (Gur, 1975; Gur & Gur, 197.5; Gur et al., 1975) have published evidence which may explain why some studies find stereotyped CLEM patterns, irrespective of task, while others report questionspecific eye shifts. When the experimenter was in a face-to-face confrontation with the subject, CLEMS tended to be characteristically consistent for individuals; however, when the experimenter was not in the subject’s visual field (i.e., videotaped or experimenter-behind-subject condition), direction of gaze deviations became related to the cognitive demands of problems. The authors have argued that an interviewer’s presence before a subject may be anxiety provoking and threatening, resulting in subjects resorting to stereotyped modes of responding involving one or the other cerebral hemisphere. In contrast, the absence of a faceto-face encounter may be associated with low arousal, consequently each hemisphere may be activated by the appropriate type of problem as indicated by gaze direction. This hypothesis appears to be supported by Ehrlichman and Weinberger’s (1978) conclusions that most of the studies in which CLEMS were found to be largely unidirectional were conducted in a face-to-face interview, while those reporting an interaction between type of task and CLEM direction were conducted under videotaped conditions with the experimenter either behind the subject or in another room. Subsequent investigations (Erwin, McClanahan, & Kleinman, 1980; Hiscock, 1977) have shown that while CLEM direction was more sensitive to question type under low arousal, it tended to be unidirectional (i.e., independent of task) under greater arousal. Erwin et al. asked their subjects embarrassing questions (e.g., “What happened on your first date?“) and found such a relationship, whereas Hiscock produced greater anxiety in one group of subjects by informing them that questions constituted an oral intelligence test and that their scores would be announced. In the latter study, another group did not receive the anxiety manipulation; both heard problems via a tape recorder positioned behind them. Those in the anxiety condition reported themselves as more tense, less happy, angrier, and less confident. Moreover, there was a significant correlation between low anxiety and subjects’ tendency to move their eyes “appropriately,” depending on the verbal or spatial content of the question. Nevertheless, an important dilemma for the anxiety or arousal hypothesis of the Gurs is the finding of a significant interaction between problem type and gaze direction in a few studies employing the supposed “anxiety-
330
RAND E LENHART
provoking” experimenter-facing-subject format (Galin & Ornstein, 1974; Kocel, Galin, Ornstein, & Merritt, 1972). In a comparison of studies utilizing this interview condition, Ehrlichman and Weinberger noted that distance between subject and experimenter varied substantially (or, more frequently, was not reported), resulting in a pattern suggesting stereotyped CLEMS at closer distances and problem-specific eye movements at further distances. Indeed, for the studies reviewed, not one using a distance less than 1.22 m found an interaction of CLEM direction and question type, while all of those exceeding 1.37 m obtained such a result. If the Gurs’ are correct that subject anxiety significantly alters CLEM patterns and if Ehrlichman and Weinberger are right that anxiety can be influenced directly by varying distance between interrogator and respondent, several further hypotheses are warranted. First, in a face-toface interview when interactants are at a close, personal distance reactive eye shifts should be stereotypic for individuals regardless of cognitive task; these same subjects also should report relatively greater anxiety. By contrast, it is expected that the differential cognitive demands of verbal and spatial problems will determine CLEM patterns when interactants are at a further, social distance and that subjects will report relatively less anxiety at this distance. Second, if different tasks do indeed preferentially activate the cerebral halves, one might expect task performance to be dependent on the “appropriateness” of the hemisphere engaged. The few researchers (Gut-, 1975; Hiscock, 1977; Kinsbourne, 1972; Weiten & Etaugh, 1974) investigating this relationship have found success in responding to be unrelated to eye movement patterns. The present study includes two improvements in this regard: the construction of questions with clearly defined correct responses presented in a forced-choice paradigm, and the inclusion of female subjects, who largely have been excluded from CLEM studies due to the general finding (Sherman, 1979) that males are more discretely lateralized than females. Regardless of sex, it is hypothesized that righthemisphere activation (left CLEMS) will be associated with correct answers to spatial questions while left-hemisphere arousal (right CLEMS) should be associated with accurate responding to verbal items. METHOD
Subjects Right-handed undergraduates at the State University of New York at Buffalo (24 males and 24 females) were the subjects. Only those with no sinistrality among their parents were included.
Questions
to Elicit
CLEMS
Stimuli to .elicit eye movements consisted of 10 verbal and 10 spatial questions. Verbal items included definitions, synonyms, analogies, comparisons, logical, and phonemic questions.
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LATERAL
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331
Spatial problems consisted of visual memory, image manipulation, spatial orientation, and miscellaneous visualizations. Items were derived from Hiscock’s (1977) questions, or were formulated on the basis of WARS-R or Stanford-Binet items. Questions were constructed such that the last word was crucial to formulating answers, one-word responses were sufficient, and items were storable for correctness. Each item consisted of a question followed by four (or two) alternatives, one of which was correct. An example of a verbal item was “What is the meaning of the word ‘ponder’? (a) hesitate (b) doubt (c) deliberate (d) delay.” An example of a spatial question was “Which direction would you be facing if east was to your left? (a) north (b) east (c) south (d) west.” Half of the subjects received the problems in the order VSSV and half order SVVS.
Procedure Equal numbers of males and females were randomly assigned to two conditions: (1) seated at a “personal” distance (0.6 m) (Near) or (2) seated at a “social” distance (1.8 m) (Far) from the investigator (male). Subjects were seated in front of a table facing the experimenter and a one-way mirror. The table served the function of a natural barrier to determine distances between participants. Subjects were told they would be asked a series of questions, each of which would be followed by alternatives read aloud from which to choose the correct response. In order to obtain the subject’s central fixation prior to the end of each problem, the examiner attempted to withhold the last three words of each question until eye contact was established. Subjects were asked to formulate an answer and to indicate (by raising their hand) when they desired the alternatives. Subjects indicated their selection by signaling with the fingers of the raised hand the number, by order, of their choice. Indicating hand was counterbalanced. Subjects were told that these signals were the focus of videotaping. Postexperimental inquiry showed that no subject suspected that eyes were being monitored. Eye movements were recorded through the one-way mirror with a zoom lens attached to a video camera. The camera was positioned directly above the interviewer, who also recorded gaze shifts. A valid eye deviation was defined as any shift in focus away from central fixation (i.e., breaking eye contact with the experimenter). A second experimenter independently scored the videotaped CLEMS; interrater agreement on direction of valid CLEMS was 91%. Pilot data indicated the necessity for including a large block of practice trials (N = 20) to allow for acclimatization to the experimental environment. Subsequently, subjects were asked the 20 experimental trials. The final data collected were responses on the state anxiety scale of the State-Trait Anxiety Inventory (STAB, developed by Spielberger, Gorsuch, and Lushene (1970), administered directly after experimental trials. Subjects completed these items only with respect to their feelings, thoughts, and attitudes during the interview.
Scoring Recordings of subjects’ initial gaze deviations at the end of each problem were categorized as (1) any detectable lateral component (right or left) or (2) the absence of a lateral shift (up, down, stare, and eyes closed). Only eye movements in the first category were included in the analyses, and lateral shifts with vertical components (e.g., right and up) were included. The number of left- and right-going eye deviations occurring during both question types was calculated for each subject. Raw data were modified to yield a proportion R L/R + L, where R and L represent the number of right and left CLEMS, respectively. Scores could range from - 1 to + 1, with a score greater than 0 indicative of proportionally more right-looking CLEMS while a score less than 0 signified proportionally more lefttending CLEMS.
332
RAND
E LENHART
RESULTS Anxiety
and Distance
Manipulation
STAI state-anxiety scores were calculated for each subject; Table 1 provides the means for males and females in both Near and Far conditions. An ANOVA was performed on the data with sex (male and female) and distance manipulation (Near and Far) as between factors. A significant interaction of sex and distance was discovered, F(1, 44) = 12.11, p < .Ol, and analysis of the simple main effect determined that for males only the mean of 41.67 for the Far group was significantly greater than the mean of 28.75 for the Near group, a reversal of the pattern predicted by the Gurs’ model, F(1, 44) = 13.32, p < .OOl. Although females produced results in line with this hypothesis (i.e., decreased anxiety with increased distance), the means did not differ significantly. CLEMS
and Distance
Manipulation
Mean proportions of right and left CLEMS to verbal and spatial problems for males and females in both the Near and Far conditions are presented in Fig. 1. An ANOVA was performed on these data with sex and distance as between factors and question type (verbal and spatial) as a repeated variable. A main effect for gender was obtained, F(1, 44) = 5.67, p < .05, with the mean of + .34 for men greater than the mean of - .04 for women. That is, overall, males tended to more often look to the right while females displayed essentially no lateral preference in gaze direction. This finding was qualified by a significant sex x distance interaction, F(1, 44) = 7.93, p < .Ol. Analysis of simple main effects indicated that the mean proportions for the two sexes differed only at the Near distance, F(1, 44) = 12.02, p < .Ol. Males produced a mean proportion of + .56 and females of - .28. These same means for the Far condition were + .13 and + .20, respectively. Thus, at the Far distance both sexes demonstrated, a weak tendency toward right looking, whereas at the Near distance males displayed an even stronger bias for right CLEMS and females now TABLE MEAN REPORTED STAI FOR MALES AND FEMALES AND
FAR
1 STATE-ANXIETY INTERROGATED
SCORES AT NEAR
DISTANCES
Distance Sex
Near
Far
Male Females
28.75 37.92
41.67 33.42
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333
FIG. 1. Proportions (R - L/R + L) of conjugate lateral eye movements (CLEMS) to the left or right in response to spatial (0) and verbal (0) questions provided by male and female subjects. Proportions above 0 represent more right-going CLEMS while proportions below 0 signify more left-moving CLEMS.
exhibited a preference for left CLEMS. These results confirm that distance manipulation had a significant impact on CLEM patterns, but that there are important gender differences in this regard. A significant interaction of problem type and distance condition was also found, F(1, 44) = 5.53, p < .05. Analysis of simple main effects demonstrated that the mean proportions of + .28 for verbal items and + .05 for spatial ones differed significantly, but only among the Far group, F(1, 44) = 6.11, p < .05. Figure 1 displays this interaction. For subjects in the Near condition the verbal mean was + .I1 and the spatial mean was + .18. This indicates a weak preference for right-moving CLEMS regardless of question type for subjects interviewed at the Near distance. Therefore, only for those interrogated at the Far distance were CLEMS problem dependent, as there was proportionally more right looking to verbal items as compared to spatial questions. This result confirms the prediction that the relationship between CLEM direction and problem type would be altered by manipulating interpersonal distance, and that this relationship was in the expected direction. Relationship between CLEMS and Anxiety
In order to determine the relationship between anxiety and CLEM direction, proportions of right and left CLEMS during each problem type for males and females in both distance conditions were correlated with state-anxiety scores. Left looking in response to spatial items was associated with anxiety scores for males in both the NEAR and FAR conditions: r = - .61 and r = - .63, p < .05, respectively. Thus, males showed a predominance of left CLEMS when both contemplating spatial problems and experiencing relatively greater anxiety.
334 Accuracy
RAND
E LENHART
of Answers
Subjects’ nonverbally indicated responses to problems were scored according to general knowledge, or scoring criteria provided in the WAIS-R and Stanford-Binet. The number of correct responses to verbal and spatial items provided by males and females in the two distance groups was calculated. A 2 (sex) x 2 (distance) x 2 (question type) ANOVA with repeated measures on the last variable was performed on the data. A main effect of question type was observed, as subjects were more often accurate to spatial items (6.43) than to verbal questions (5.87), F(1, 44) = 5.06, p < .05. In addition, there was a main effect of sex, F( 1,44) = 5.75, p < .05. The mean of 13.38 for correct responses supplied by males was significantly greater than the mean of 11.21 for females. Although males performed better than females overall, both groups performed significantly above chance. The means represent accuracy rates of 66.88 and 56.05%, respectively, and significant b < .05) deviation scores of Z = 4.00 and Z ‘= 2.91, respectively. CLEMS,
Accuracy
of Responses
and Distance
Manipulation
Proportions of right and left CLEMS for each subject in each of the four groups for correct and incorrect responses to verbal and spatial problems were calculated. A 2 (sex) x 2 (distance) x 2 (question type) x 2 (accuracy-correct or incorrect) ANOVA with repeated measures on the last two factors was conducted on the data. A significant interaction of question type and accuracy was discovered, F(1, 44) = 4.29, p < .05; analysis of the simple interaction indicated that the mean proportions differed for verbal and spatial items only when CLEMS were accompanied by correct responses, F(1,44) = 4.19, p < .05. When subjects answered questions correctly the mean proportion was + .26 for verbal problems and - .Ol for spatial questions. These same means were + .14 and + .16, respectively, for incorrect responses; that is, a small bias toward righttending CLEMS was demonstrated regardless of the type of question. In contrast, when correct answers were supplied, verbal problems were associated with somewhat stronger right looking while gazes to spatial questions contained more left CLEMS so that a slight bias toward left shifting was observed. This finding follows the prediction that “appropriateness” of the aroused hemisphere, as signified by CLEM direction, is related to correctness in responding to problems. DISCUSSION
The CLEM data of this investigation support the prediction (Ehrlichman & Weinberger, 1978) that interpersonal distance between subject and experimenter in a face-to-face questioning format can have a significant impact on observed reactive gaze patterns. Moreover, the results provide a plausible explanation for the discrepancy between those studies which
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335
report strong individual preferences in eye movement direction and those which do not when using this interviewing condition. Namely, interrogating at a closer, more “personal” distance (Near) produces stereotypic CLEMS which are not problem specific, while questioning at a further, “consultative” distance (Far) results in gaze shifts which are dependent on the nature of the task. In the present experiment, examining subjects at a Near distance resulted in a slight bias toward right-going CLEMS, regardless of question type. However, when subjects were interviewed at a Far distance, eye movement patterns were related to the type of problem; verbal queries elicited proportionally more right looking than spatial questions. This finding not only follows the assertions of Ehrlichman and Weinberger regarding the effect of distance on CLEM patterns, it is congruent with previous research indicating relatively greater lefthemisphere arousal (i.e., more frequent right-tending gazes) in response to verbal items as compared to spatial problems (Galen & Ornstein, 1974; Kinsbourne, 1972; Schwartz et al., 1975). With respect to an explanation of these results based on differential subject anxiety, the findings herein disconfirm the anxiety hypothesis of the Gurs (Gur, 1975; Gur & Gur, 1975; Gur et al., 1975) which predicts that subjects should produce stereotyped CLEM patterns when feeling anxious or threatened, while low arousal should be associated with CLEMS reflecting differential activation of the two hemispheres during verbal and spatial processing. Contrary to this prediction, males in the Far condition reported significantly more anxiety than their counterparts in the Near condition; females in the Far condition expressed only slightly less anxiety than those Near. Thus, although social distance had a substantial effect on gaze deviation patterns in the expected direction, the results with regard to self-reported anxiety indicate that subject anxiety cannot account for this effect. Hiscock (1977) similarly discovered that anxiety does not underlie the effects of face-to-face interrogation, despite the fact that under this condition subjects tended to look consistently to one side or the other. In the present experiment the only significant association between CLEM direction and anxiety was that males overall produced the most left looking (right-hemisphere arousal) while both processing spatial information and experiencing relatively greater anxiety, a finding consistent with prior results showing nondominant hemisphere involvement in both spatial (Kinsbourne, 1972) and emotional (Schwartz et al., 1975) processing. Furthermore, manipulating distance between interactants in this study differentially affected CLEM patterns for the two sexes. For males, a weak preference for right-moving CLEMS was observed at the Near distance; with decreased distance the proclivity toward right looking strengthened. Females at the FAR distance also demonstrated a small bias toward right-going gazes. However, when interviewed at the Near
336
RAND E LENHART
distance a strong preference for left-tending CLEMS was observed. This finding once again confirms the relationship between distance and gaze deviation patterns, but particularly for males. Also, once again, differences in subject anxiety cannot explain this finding as males reported greater anxiety at the longer distance. The results for females are difficult to explain in view of the limited research with this population. It is not clear why females would show a preference for right CLEMS when Near and a tendency toward left CLEMS when Far. Previous research shows that women are more likely to be left movers while men are more likely to be right movers (Weiten & Etaugh, 1974), a finding which was replicated in this study, but only when subjects were at the Far distance. Clearly, further studies are needed in order to elucidate this relationship. Finally, if CLEM direction reflects contralateral hemisphere activation, one could predict that performance on verbal and spatial problems would be dependent on the hemisphere aroused by subjects. Although earlier research (Gur, 1975; Hiscock, 1977; Kinsbourne, 1972; Weiten & Etaugh, 1974) has failed to demonstrate this relationship, in the present study accuracy of subjects’ responses was related to CLEM direction. Specifically, subjects gazed to their right (left-hemisphere activation) relatively more often in response to verbal as compared to spatial tasks, but only when CLEMS were accompanied by correct answers. When subjects’ answers were incorrect this relationship was no longer significant. These results indicate, then, that activation of the “appropriate” hemisphere, as indicated by CLEM direction during cognitive effort, may be crucial to formulating correct responses to cognitive tasks. The current investigation included certain controls not present in other experiments (e.g., a forced-choice paradigm with clearly defined correct responses), and this may explain the significance of these results. REFERENCES Bakan, P. 1%9. Hypnotizability, Perceptual
and Motor
Skills,
laterality of eye movements and functional brain asymmetry. 28, 927-932.
Dewitt, G. W., & Averill, J. R. 1976. Lateral eye movements, hypnotic susceptibility and field independence-dependence. Perceptual and Motor Skills, 43, 1179-1184. Duke, J. D. 1968. Lateral eye movement behavior. Journal of General Psychology, 78, 189-195. Ehrlichman, H., & Weinberger, A. 1978. Lateral eye movement and hemispheric asymmetry: A critical review. Psychological Bulletin, 85, 1080-l 101. Erwin, R. J., McClanahan, B. A., & Kleinman, D. M. 1980. Effects of level of arousal and type of task on bilateral skin conductance asymmetry and conjugate lateral eye movements. Pavlovian Journal of Biological Sciences, 15, 59-67. Galin, D., & Ornstein, R. 1974. Individual differences in cognitive style. I. Reflective eye movements. Neuropsychologia, 12, 367-376. Gur, R. E. 1975. Conjugate lateral eye movements as an index of hemispheric activation. Journal
of Personality
and Social
Psychology,
31(4),
751-757.
Gur, R. E., & Gur, R. C. 1975. Defense mechanisms, psychosomatic symptomatology, and conjugate lateral eye movements. Journal of Consulting and Clinical Psychology, 43, 416-420.
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Cur, R. E., Gur, R. C., & Harris, L. J. 1975. Cerebral activation, as measured by subjects’ lateral eye movements, is influenced by experimenter location. Neuropsychologia, 13, 35-44. Hiscock, M. 1977. Effects of examiner’s location and subject’s anxiety on gaze laterality. Neuropsychologia,
15, 409-416.
Kinsboume,
M. 1972. Eye and head turning indicates cerebral lateralization. Science (Washington, D.C.), 176, 539-541. Kocel, K., Galin, D., Omstein, R., & Merritt, E. L. 1972. Lateral eye movement and cognitive mode. Psychonomic Science, 27, 223-224. Schwartz, G. E., Davidson, R. J., & Maer, F. 1975. Right hemisphere lateralization for emotion in the human brain: Interactions with cognition. Science (Washington, D.C.), 190, 286-288.
Sherman, J. 1979. Cognitive performance as a function of sex and handedness: An evaluation of the Levy hypothesis. Psychology of Women Quarterly, 3, 378-390. Spielberger, C. D., Gorsuch, R. L., & Lushene, R. E. 1970. Manual for the State-Trait Anxiety Inventory (self-evaluation survey). Palo Alto, CA: Consulting Psychologist Press. Weiten, W., & Eta@, C. F. 1973. Lateral eye-movement as related to verbal and perceptualmotor skills and values. Perceptual and Motor Skills, 39, 481-482. Weiten, W., & Etaugh, C. F. 1974. Lateral eye-movement as a function of cognitive mode, question sequence and sex of subject. Perceptual and Motor Skills, 38, 439-444.
AND
COGNITION
4, 328-337 (1985)
The Effects of Distance between Interactants and Subject Anxiety on Conjugate Lateral Eye Movements RAND E LENHART V. A. Medical
Center,
Palo Alto,
California
and State
University
of New
York
at Buffalo
Ehrlichman and Weinberger (1978, Psychological Bulletin 85, 1080-l 101) have suggested that the distance between participants during face-to-face interviewing may be a significant determinant of directional patterns of conjugate lateral eye movements (CLEMS). As predicted, at the longer, social distance CLEMS were dependent on the verbal or spatial nature of questions; when interactants were at a closer, personal distance CLEMS became more consistent in direction, regardless of problem type. Distance manipulation also differentially altered CLEM patterns for the two sexes. 8 1985 Academic Press. IK.
Conjugate lateral eye movements (CLEMS), spontaneous reactive gaze shifts to the right or left during reflective thinking, are presumed to reflect contralateral cerebral hemispheric activation (Duke, 1968; Galin & Omstein, 1974; Gur, Gut-, & Harris, 1975; Kinsbourne, 1972). A consistent finding in CLEM research is that subjects tend to display a characteristic direction of averting the eyes so that each may be classified as a “right mover,” “left mover,” or “bidirectional” (Duke, 1968; Gur et al., 1975). Bakan (1969) attempted to explain this evidence for “individual hemisphericity,” that is, a tendency to rely most heavily on the processing mode of one hemisphere, in terms of relative dominance of one cerebral half over the other; CLEMS represent easier activation of the hemisphere contralateral to the direction of eye movement. Subsequent studies have revealed that individuals with similar CLEM patterns also have cognitive and personality profiles resembling one another (Dewitt & Aver-ill, 1976; Gur & Gur, 1975; Hiscock, 1977; Weiten & Etaugh, 1973). An alternative research strategy has focused on the effects of specific types of tasks upon the direction of CLEMS (Galin & Ornstein, 1974; Kinsbourne, 1972; Schwartz, Davidson, & Maer, 1975). The majority of these studies have shown spatial and emotional questions to evoke more Address requests for reprints to Rand E Lenhart, Ph.D., Psychology Service 116B, V. A. Medical Center, 3801 Miranda Ave., Palo Alto, CA 94304. 328 0278-2626185 $3.00 Copyright All rights
6 1985 by Academic Press, Inc. of reproduction in any form reserved.
CONJUGATE
LATERAL
EYE
MOVEMENTS
329
frequent left CLEMS, whereas verbal and numerical problems have produced more right-going gaze shifts. Analogous to the “hemisphericity” model, these results have been attributed to the differential activation of the two cerebral hemispheres as a consequence of the cognitive demands of differing problems. Recently, the Gurs (Gur, 1975; Gur & Gur, 197.5; Gur et al., 1975) have published evidence which may explain why some studies find stereotyped CLEM patterns, irrespective of task, while others report questionspecific eye shifts. When the experimenter was in a face-to-face confrontation with the subject, CLEMS tended to be characteristically consistent for individuals; however, when the experimenter was not in the subject’s visual field (i.e., videotaped or experimenter-behind-subject condition), direction of gaze deviations became related to the cognitive demands of problems. The authors have argued that an interviewer’s presence before a subject may be anxiety provoking and threatening, resulting in subjects resorting to stereotyped modes of responding involving one or the other cerebral hemisphere. In contrast, the absence of a faceto-face encounter may be associated with low arousal, consequently each hemisphere may be activated by the appropriate type of problem as indicated by gaze direction. This hypothesis appears to be supported by Ehrlichman and Weinberger’s (1978) conclusions that most of the studies in which CLEMS were found to be largely unidirectional were conducted in a face-to-face interview, while those reporting an interaction between type of task and CLEM direction were conducted under videotaped conditions with the experimenter either behind the subject or in another room. Subsequent investigations (Erwin, McClanahan, & Kleinman, 1980; Hiscock, 1977) have shown that while CLEM direction was more sensitive to question type under low arousal, it tended to be unidirectional (i.e., independent of task) under greater arousal. Erwin et al. asked their subjects embarrassing questions (e.g., “What happened on your first date?“) and found such a relationship, whereas Hiscock produced greater anxiety in one group of subjects by informing them that questions constituted an oral intelligence test and that their scores would be announced. In the latter study, another group did not receive the anxiety manipulation; both heard problems via a tape recorder positioned behind them. Those in the anxiety condition reported themselves as more tense, less happy, angrier, and less confident. Moreover, there was a significant correlation between low anxiety and subjects’ tendency to move their eyes “appropriately,” depending on the verbal or spatial content of the question. Nevertheless, an important dilemma for the anxiety or arousal hypothesis of the Gurs is the finding of a significant interaction between problem type and gaze direction in a few studies employing the supposed “anxiety-
330
RAND E LENHART
provoking” experimenter-facing-subject format (Galin & Ornstein, 1974; Kocel, Galin, Ornstein, & Merritt, 1972). In a comparison of studies utilizing this interview condition, Ehrlichman and Weinberger noted that distance between subject and experimenter varied substantially (or, more frequently, was not reported), resulting in a pattern suggesting stereotyped CLEMS at closer distances and problem-specific eye movements at further distances. Indeed, for the studies reviewed, not one using a distance less than 1.22 m found an interaction of CLEM direction and question type, while all of those exceeding 1.37 m obtained such a result. If the Gurs’ are correct that subject anxiety significantly alters CLEM patterns and if Ehrlichman and Weinberger are right that anxiety can be influenced directly by varying distance between interrogator and respondent, several further hypotheses are warranted. First, in a face-toface interview when interactants are at a close, personal distance reactive eye shifts should be stereotypic for individuals regardless of cognitive task; these same subjects also should report relatively greater anxiety. By contrast, it is expected that the differential cognitive demands of verbal and spatial problems will determine CLEM patterns when interactants are at a further, social distance and that subjects will report relatively less anxiety at this distance. Second, if different tasks do indeed preferentially activate the cerebral halves, one might expect task performance to be dependent on the “appropriateness” of the hemisphere engaged. The few researchers (Gut-, 1975; Hiscock, 1977; Kinsbourne, 1972; Weiten & Etaugh, 1974) investigating this relationship have found success in responding to be unrelated to eye movement patterns. The present study includes two improvements in this regard: the construction of questions with clearly defined correct responses presented in a forced-choice paradigm, and the inclusion of female subjects, who largely have been excluded from CLEM studies due to the general finding (Sherman, 1979) that males are more discretely lateralized than females. Regardless of sex, it is hypothesized that righthemisphere activation (left CLEMS) will be associated with correct answers to spatial questions while left-hemisphere arousal (right CLEMS) should be associated with accurate responding to verbal items. METHOD
Subjects Right-handed undergraduates at the State University of New York at Buffalo (24 males and 24 females) were the subjects. Only those with no sinistrality among their parents were included.
Questions
to Elicit
CLEMS
Stimuli to .elicit eye movements consisted of 10 verbal and 10 spatial questions. Verbal items included definitions, synonyms, analogies, comparisons, logical, and phonemic questions.
CONJUGATE
LATERAL
EYE MOVEMENTS
331
Spatial problems consisted of visual memory, image manipulation, spatial orientation, and miscellaneous visualizations. Items were derived from Hiscock’s (1977) questions, or were formulated on the basis of WARS-R or Stanford-Binet items. Questions were constructed such that the last word was crucial to formulating answers, one-word responses were sufficient, and items were storable for correctness. Each item consisted of a question followed by four (or two) alternatives, one of which was correct. An example of a verbal item was “What is the meaning of the word ‘ponder’? (a) hesitate (b) doubt (c) deliberate (d) delay.” An example of a spatial question was “Which direction would you be facing if east was to your left? (a) north (b) east (c) south (d) west.” Half of the subjects received the problems in the order VSSV and half order SVVS.
Procedure Equal numbers of males and females were randomly assigned to two conditions: (1) seated at a “personal” distance (0.6 m) (Near) or (2) seated at a “social” distance (1.8 m) (Far) from the investigator (male). Subjects were seated in front of a table facing the experimenter and a one-way mirror. The table served the function of a natural barrier to determine distances between participants. Subjects were told they would be asked a series of questions, each of which would be followed by alternatives read aloud from which to choose the correct response. In order to obtain the subject’s central fixation prior to the end of each problem, the examiner attempted to withhold the last three words of each question until eye contact was established. Subjects were asked to formulate an answer and to indicate (by raising their hand) when they desired the alternatives. Subjects indicated their selection by signaling with the fingers of the raised hand the number, by order, of their choice. Indicating hand was counterbalanced. Subjects were told that these signals were the focus of videotaping. Postexperimental inquiry showed that no subject suspected that eyes were being monitored. Eye movements were recorded through the one-way mirror with a zoom lens attached to a video camera. The camera was positioned directly above the interviewer, who also recorded gaze shifts. A valid eye deviation was defined as any shift in focus away from central fixation (i.e., breaking eye contact with the experimenter). A second experimenter independently scored the videotaped CLEMS; interrater agreement on direction of valid CLEMS was 91%. Pilot data indicated the necessity for including a large block of practice trials (N = 20) to allow for acclimatization to the experimental environment. Subsequently, subjects were asked the 20 experimental trials. The final data collected were responses on the state anxiety scale of the State-Trait Anxiety Inventory (STAB, developed by Spielberger, Gorsuch, and Lushene (1970), administered directly after experimental trials. Subjects completed these items only with respect to their feelings, thoughts, and attitudes during the interview.
Scoring Recordings of subjects’ initial gaze deviations at the end of each problem were categorized as (1) any detectable lateral component (right or left) or (2) the absence of a lateral shift (up, down, stare, and eyes closed). Only eye movements in the first category were included in the analyses, and lateral shifts with vertical components (e.g., right and up) were included. The number of left- and right-going eye deviations occurring during both question types was calculated for each subject. Raw data were modified to yield a proportion R L/R + L, where R and L represent the number of right and left CLEMS, respectively. Scores could range from - 1 to + 1, with a score greater than 0 indicative of proportionally more right-looking CLEMS while a score less than 0 signified proportionally more lefttending CLEMS.
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RESULTS Anxiety
and Distance
Manipulation
STAI state-anxiety scores were calculated for each subject; Table 1 provides the means for males and females in both Near and Far conditions. An ANOVA was performed on the data with sex (male and female) and distance manipulation (Near and Far) as between factors. A significant interaction of sex and distance was discovered, F(1, 44) = 12.11, p < .Ol, and analysis of the simple main effect determined that for males only the mean of 41.67 for the Far group was significantly greater than the mean of 28.75 for the Near group, a reversal of the pattern predicted by the Gurs’ model, F(1, 44) = 13.32, p < .OOl. Although females produced results in line with this hypothesis (i.e., decreased anxiety with increased distance), the means did not differ significantly. CLEMS
and Distance
Manipulation
Mean proportions of right and left CLEMS to verbal and spatial problems for males and females in both the Near and Far conditions are presented in Fig. 1. An ANOVA was performed on these data with sex and distance as between factors and question type (verbal and spatial) as a repeated variable. A main effect for gender was obtained, F(1, 44) = 5.67, p < .05, with the mean of + .34 for men greater than the mean of - .04 for women. That is, overall, males tended to more often look to the right while females displayed essentially no lateral preference in gaze direction. This finding was qualified by a significant sex x distance interaction, F(1, 44) = 7.93, p < .Ol. Analysis of simple main effects indicated that the mean proportions for the two sexes differed only at the Near distance, F(1, 44) = 12.02, p < .Ol. Males produced a mean proportion of + .56 and females of - .28. These same means for the Far condition were + .13 and + .20, respectively. Thus, at the Far distance both sexes demonstrated, a weak tendency toward right looking, whereas at the Near distance males displayed an even stronger bias for right CLEMS and females now TABLE MEAN REPORTED STAI FOR MALES AND FEMALES AND
FAR
1 STATE-ANXIETY INTERROGATED
SCORES AT NEAR
DISTANCES
Distance Sex
Near
Far
Male Females
28.75 37.92
41.67 33.42
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FIG. 1. Proportions (R - L/R + L) of conjugate lateral eye movements (CLEMS) to the left or right in response to spatial (0) and verbal (0) questions provided by male and female subjects. Proportions above 0 represent more right-going CLEMS while proportions below 0 signify more left-moving CLEMS.
exhibited a preference for left CLEMS. These results confirm that distance manipulation had a significant impact on CLEM patterns, but that there are important gender differences in this regard. A significant interaction of problem type and distance condition was also found, F(1, 44) = 5.53, p < .05. Analysis of simple main effects demonstrated that the mean proportions of + .28 for verbal items and + .05 for spatial ones differed significantly, but only among the Far group, F(1, 44) = 6.11, p < .05. Figure 1 displays this interaction. For subjects in the Near condition the verbal mean was + .I1 and the spatial mean was + .18. This indicates a weak preference for right-moving CLEMS regardless of question type for subjects interviewed at the Near distance. Therefore, only for those interrogated at the Far distance were CLEMS problem dependent, as there was proportionally more right looking to verbal items as compared to spatial questions. This result confirms the prediction that the relationship between CLEM direction and problem type would be altered by manipulating interpersonal distance, and that this relationship was in the expected direction. Relationship between CLEMS and Anxiety
In order to determine the relationship between anxiety and CLEM direction, proportions of right and left CLEMS during each problem type for males and females in both distance conditions were correlated with state-anxiety scores. Left looking in response to spatial items was associated with anxiety scores for males in both the NEAR and FAR conditions: r = - .61 and r = - .63, p < .05, respectively. Thus, males showed a predominance of left CLEMS when both contemplating spatial problems and experiencing relatively greater anxiety.
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of Answers
Subjects’ nonverbally indicated responses to problems were scored according to general knowledge, or scoring criteria provided in the WAIS-R and Stanford-Binet. The number of correct responses to verbal and spatial items provided by males and females in the two distance groups was calculated. A 2 (sex) x 2 (distance) x 2 (question type) ANOVA with repeated measures on the last variable was performed on the data. A main effect of question type was observed, as subjects were more often accurate to spatial items (6.43) than to verbal questions (5.87), F(1, 44) = 5.06, p < .05. In addition, there was a main effect of sex, F( 1,44) = 5.75, p < .05. The mean of 13.38 for correct responses supplied by males was significantly greater than the mean of 11.21 for females. Although males performed better than females overall, both groups performed significantly above chance. The means represent accuracy rates of 66.88 and 56.05%, respectively, and significant b < .05) deviation scores of Z = 4.00 and Z ‘= 2.91, respectively. CLEMS,
Accuracy
of Responses
and Distance
Manipulation
Proportions of right and left CLEMS for each subject in each of the four groups for correct and incorrect responses to verbal and spatial problems were calculated. A 2 (sex) x 2 (distance) x 2 (question type) x 2 (accuracy-correct or incorrect) ANOVA with repeated measures on the last two factors was conducted on the data. A significant interaction of question type and accuracy was discovered, F(1, 44) = 4.29, p < .05; analysis of the simple interaction indicated that the mean proportions differed for verbal and spatial items only when CLEMS were accompanied by correct responses, F(1,44) = 4.19, p < .05. When subjects answered questions correctly the mean proportion was + .26 for verbal problems and - .Ol for spatial questions. These same means were + .14 and + .16, respectively, for incorrect responses; that is, a small bias toward righttending CLEMS was demonstrated regardless of the type of question. In contrast, when correct answers were supplied, verbal problems were associated with somewhat stronger right looking while gazes to spatial questions contained more left CLEMS so that a slight bias toward left shifting was observed. This finding follows the prediction that “appropriateness” of the aroused hemisphere, as signified by CLEM direction, is related to correctness in responding to problems. DISCUSSION
The CLEM data of this investigation support the prediction (Ehrlichman & Weinberger, 1978) that interpersonal distance between subject and experimenter in a face-to-face questioning format can have a significant impact on observed reactive gaze patterns. Moreover, the results provide a plausible explanation for the discrepancy between those studies which
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report strong individual preferences in eye movement direction and those which do not when using this interviewing condition. Namely, interrogating at a closer, more “personal” distance (Near) produces stereotypic CLEMS which are not problem specific, while questioning at a further, “consultative” distance (Far) results in gaze shifts which are dependent on the nature of the task. In the present experiment, examining subjects at a Near distance resulted in a slight bias toward right-going CLEMS, regardless of question type. However, when subjects were interviewed at a Far distance, eye movement patterns were related to the type of problem; verbal queries elicited proportionally more right looking than spatial questions. This finding not only follows the assertions of Ehrlichman and Weinberger regarding the effect of distance on CLEM patterns, it is congruent with previous research indicating relatively greater lefthemisphere arousal (i.e., more frequent right-tending gazes) in response to verbal items as compared to spatial problems (Galen & Ornstein, 1974; Kinsbourne, 1972; Schwartz et al., 1975). With respect to an explanation of these results based on differential subject anxiety, the findings herein disconfirm the anxiety hypothesis of the Gurs (Gur, 1975; Gur & Gur, 1975; Gur et al., 1975) which predicts that subjects should produce stereotyped CLEM patterns when feeling anxious or threatened, while low arousal should be associated with CLEMS reflecting differential activation of the two hemispheres during verbal and spatial processing. Contrary to this prediction, males in the Far condition reported significantly more anxiety than their counterparts in the Near condition; females in the Far condition expressed only slightly less anxiety than those Near. Thus, although social distance had a substantial effect on gaze deviation patterns in the expected direction, the results with regard to self-reported anxiety indicate that subject anxiety cannot account for this effect. Hiscock (1977) similarly discovered that anxiety does not underlie the effects of face-to-face interrogation, despite the fact that under this condition subjects tended to look consistently to one side or the other. In the present experiment the only significant association between CLEM direction and anxiety was that males overall produced the most left looking (right-hemisphere arousal) while both processing spatial information and experiencing relatively greater anxiety, a finding consistent with prior results showing nondominant hemisphere involvement in both spatial (Kinsbourne, 1972) and emotional (Schwartz et al., 1975) processing. Furthermore, manipulating distance between interactants in this study differentially affected CLEM patterns for the two sexes. For males, a weak preference for right-moving CLEMS was observed at the Near distance; with decreased distance the proclivity toward right looking strengthened. Females at the FAR distance also demonstrated a small bias toward right-going gazes. However, when interviewed at the Near
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distance a strong preference for left-tending CLEMS was observed. This finding once again confirms the relationship between distance and gaze deviation patterns, but particularly for males. Also, once again, differences in subject anxiety cannot explain this finding as males reported greater anxiety at the longer distance. The results for females are difficult to explain in view of the limited research with this population. It is not clear why females would show a preference for right CLEMS when Near and a tendency toward left CLEMS when Far. Previous research shows that women are more likely to be left movers while men are more likely to be right movers (Weiten & Etaugh, 1974), a finding which was replicated in this study, but only when subjects were at the Far distance. Clearly, further studies are needed in order to elucidate this relationship. Finally, if CLEM direction reflects contralateral hemisphere activation, one could predict that performance on verbal and spatial problems would be dependent on the hemisphere aroused by subjects. Although earlier research (Gur, 1975; Hiscock, 1977; Kinsbourne, 1972; Weiten & Etaugh, 1974) has failed to demonstrate this relationship, in the present study accuracy of subjects’ responses was related to CLEM direction. Specifically, subjects gazed to their right (left-hemisphere activation) relatively more often in response to verbal as compared to spatial tasks, but only when CLEMS were accompanied by correct answers. When subjects’ answers were incorrect this relationship was no longer significant. These results indicate, then, that activation of the “appropriate” hemisphere, as indicated by CLEM direction during cognitive effort, may be crucial to formulating correct responses to cognitive tasks. The current investigation included certain controls not present in other experiments (e.g., a forced-choice paradigm with clearly defined correct responses), and this may explain the significance of these results. REFERENCES Bakan, P. 1%9. Hypnotizability, Perceptual
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