The effects of stressful arousal on conjugate lateral eye movement

This study investigated the relationship between stressful arousal and conjugate lateral eye movement tendencies in right-handed males. Sixty subjects were asked both neutral and mildly emotional questions after watching either a stressful industrial accident movie or a bland control film. Subjects had been previously classified as either right-movers, left-movers, or bidirectionals on the basis of their responses in a prefilm interview. A statistically significant interaction between dominant direction and film condition was found on right eye movement. Subjects classified as right-movers displayed increased right eye movement preferences under the stress film, compared to the neutral film condition. This effect was seen with neutral, but not mildly emotional, questions. Results were interpreted within an elaborated brain asymmetry model of conjugate lateral eye movement, in which stressful arousal is assumed to increase subjects' reliance on characteristic, neurologically based ways of dealing with stimuli. Implications for theory and research on brain-behavior relationships in ego-defensive styles are discussed.     

Effects of level of arousal and type of task on bilateral skin conductance asymmetry and conjugate lateral eye movements

Several recent studies have indicated that the degree and direction of bilateral skin conductance (BSC) asymmetry and the direction of conjugate lateral eye movements (CLEMs) both index hemispheric functioning. Evidence also suggests that BSC asymmetry decreases and CLEMs become more unidirectional as level of arousal increases. Thirty-two normal adults received an habituation series of five-second tones followed by 40 questions. All stimuli were tape recorded. The questions (Schwartz, Davidson, and Maer, 1975) were grouped in four series: 10 verbal-emotional, 10 verbalnonemotional, 10 spatial-emotional, and 10 spatial-nonemotional. The order in which the four series were presented was counterbalanced across subjects. Prior to each question, subjects fixated the face of a mannequin. Sixteen subjects (high arousal) had five seconds to contemplate their answer; the remaining 16 (low arousal) had 10 seconds. Instructions for the high arousal group specified that intelligence and problem-solving ability was being tested, and that speed and accuracy were very important. Those for the low arousal group indicated casually that subjects were to ponder a series of questions. BSC levels, SC response amplitudes, and CLEMs were measured during a five-second interval following each tone or question. BSC levels were greater under the High Arousal condition. While approximately two-thirds of the subjects showed BSC asymmetry (roughly evenly divided between those with larger left and right hand responses), neither the degree nor direction of the asymmetries changed as a function of question type. While CLEM direction was more sensitive to question type under low arousal, (i.e., verbal questions resulted in predominantly right-going CLEMs and spatial questions resulted in predominantly left-going CLEMs) they tended to be stereotyped (i.e., unidirectional) under high arousal. Finally, no relationship was observed between CLEM direction and BSC asymmetry under either high or low arousal condition.     

Hemispheric dominance, dichotic listening and lateral eye movement behaviour

Abstract.— Because lateral corrective eye movements have been shown to influence the results of the dichotic listening test, it was supposed that differences in the scoring on this test by right and left eye movers could be found. Only in the entire group of 22 right handed subjects and in the subgroup of 8 right eye movers a significant right ear superiority was found. In the left mover group (14 subjects) right ear superiority in dichotic listening was not significant. These results are interpreted in terms of possible interhemispheric differences in the level of "activity", facilitating or hampering perception of verbal material in the contralateral ear.     

Effects of subject-to-experimenter distance and instructions on lateral eye movement

Lateral eye movements and heart rate were recorded as 32 right-handed men answered verbal and spatial questions. Experimenter-to-subject distance (.8 and 1.5 m) and attention demand of instructions were manipulated in a 2 X 2 design. A significant main effect for distance and an interaction of distance by instructions appeared on the direction of eye movements independent of type of question. The greatest number of leftward eye movements occurred at the short distance with instructions demanding higher attention. These findings are consistent with evidence that emotional arousal produces greater right- than left-hemisphere activation.     

Degree of asymmetry in lateral preferences: eye, foot, ear.

Lateral asymmetry in eye, foot, and ear preference was measured using a 15-item questionnaire administered to 442 subjects. Degree and magnitude of asymmetry were greatest for eye, followed by foot and ear. Intercorrelations of lateral preferences were all positive and significant. Two primary factors, eyedness and earedness, were established.     

Relationship between conjugate lateral eye movements, brain organization, and cognitive style

The relationship between individual differences in conjugate lateral eye movements (CLEMs) and inferential reasoning was investigated in two experiments. Subjects were given inference tasks in sentence and pictorial form and were later tested for recognition of correct inferences as well as literal recognition of the acquisition items. In Experiment 2, for example, subjects were given logical syllogisms during acquisition. Theoretically, right-eye movement/left-hemispheric (REM/LH) subjects should have excelled at this highly logical task but no significant differences between eye-movement groups were found. However, support for previous research showing the moderating effects of gender on hemispheric activation (measured by CLEMs) and hemispheric competence came from the memory data of Experiment 2. These data indicated that male REM/LH subjects recognized more acquisition sentences than the other eye movement/gender groups. It was suggested CLEMs and other measures of hemispheric activation and competence, coupled with data collected using complex cognitive tasks, can eventually lead to explanatory brain models of cognitive processing.     

The effects of distance between interactants and subject anxiety on conjugate lateral eye movements

Ehrlichman and Weinberger (1978, Psychological Bulletin 85, 1080-1101) 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.     

Rapid eye movement sleep deprivation affects sleep similarly in castrated and noncastrated rats

Twenty-four-hour recordings of electrophysiological correlates of the sleep-waking cycle in castrated and noncastrated Wistar rats were performed to validate the cuff pedestal technique in the deprivation of rapid eye movement sleep. An undisturbed pattern of sleep was found in both castrated and noncastrated rats when the cuffs were in the raised position. The lowering of the cuff for 4 days virtually abolished REMs in both groups of rats. During neither the dark nor the light period was there any difference between the castrated and noncastrated rats in the total amount of REMs rebound. The results accord with the data obtained by the conventional flowerpot procedure and show that castration does not influence the amount of REMs before, during, and after REMs deprivation in the rat. It is suggested that testicular testosterone, contrary to growth hormone, is not essential for the triggering of REMs sleep, although both have anabolic actions.     

Conjugate lateral eye movement and latency of verbal response to arithmetic questions.

24 left movers, 24 right movers and 24 mixed movers, categorized on the basis of their conjugate lateral eye movements, were measured on latency of verbal response to arithmetic questions. The predicted superiority of right movers in speed of response did not occur nor did interference with habitual direction of conjugate lateral eye movement affect results. However, the mixed group took longer to response to a second series of questions than did the left and right movers. This post hoc finding may indicate inefficient hemispheric competition within the mixed group when subjects are asked to add another task to that of arithmetic problem-solving.     

Dominant direction of conjugate lateral eye movements and responsiveness to facial and verbal cues.

Responsiveness to facial versus verbal cues as a function of dominant direction of conjugate lateral eye movements and sex was tested in a 2 X 2 analysis of variance design. Ss were 81 student volunteers. Right-movers (n = 33) were more responsive to verbal cues; left-movers (n = 45) were more responsive to facial cues (p less than .05). The results are consistent with the hypothesized link between conjugate lateral eye movements and functional asymmetry of the cerebral hemispheres. Males were more responsive to verbal cues; females were more responsive to facial cues (p less than .05). Data relevant to reliability of the eye movements, the relationship between sex and eye movements, and the relationship between type of question and eye movements are also presented.     

Effects of question type and experimenter position on bilateral differences in electrodermal activity and conjugate lateral eye movements

28 dextral males participated in a within-subjects experiment which tasted for the effects of question type (verbal versus spatial) and experimenter-position (in front of or behind the subject) on direction of conjugate lateral eye movements (LEMs) and bilateral differences in skin conductance responses (SCRs). Question dependent asymmetries were observed for LEM direction but not for SCR magnitude. Experimenter-position had no significant effect. The results for LEM direction are consistent with the hypothesis linking eye movements to the left or right with activation of the cerebral hemisphere contralateral to the direction of gaze. The results for SCR magnitude, given certain assumptions, can be reconciled with a hemispheric model of contralateral excitatory control of that system.     

Visual search without eye movement

Two experiments have been made on the problem of visual search using six patterns which were geometrically simple, and familiar to the subject.

In each case the subject's task was to say where, among the complex of patterns, a particular pattern (the “test object”) appeared when the exposure of the whole display was so brief as to prevent scanning by the eyes. He could be informed visually (in Experiment I) or verbally (in Experiment II) which pattern was to be regarded as the “test object.”

In both experiments it was found that foreknowledge of what was to be the test object gave a significantly higher standard of accuracy than knowledge given later. This suggests that something analogous to visual search can occur without eye movements.     

3-D eye movement analysis

This paper presents a novel three-dimensional (3-D) eye movement analysis algorithm for binocular eye tracking within virtualreality (VR). The user’s gaze direction, head position, and orientation are tracked in order to allow recording of the user’s fixations within the environment. Although the linear signal analysis approach is itself not new, its application to eye movement analysis in three dimensions advances traditional two-dimensional approaches, since it takes into account the six degrees of freedom of head movements and is resolution independent. Results indicate that the 3-D eye movement analysis algorithm can successfully be used for analysis of visual process measures in VR. Process measures not only can corroborate performance measures, but also can lead to discoveries of the reasons for performance improvements. In particular, analysis of users’ eye movements in VR can potentially lead to further insights into the underlying cognitive processes of VR subjects.     

Variations in patterns of lateral asymmetry among dextrals

Evidence supporting individual variations in patterns of hemispheric involvement in the recognition of visuo-spatial and verbal stimuli among dextrals is reported. In Experiment 1, subjects' asymmetry scores on a task that was nonlateralized for the group as a whole were significantly correlated with their asymmetry scores on right-hemisphere-specialized tasks, including face recognition. In Experiment 2, subjects' asymmetry scores on a task that was nonlateralized for the group as a whole were significantly correlated with their asymmetry scores on a left-hemisphere-specialized word recognition task. These results suggest that individual dextrals' asymmetry scores on lateralized tasks are a joint function of a subject's underlying hemispheric specialization for that task and stable individual variations in asymmetric hemispheric reliance.     

The relationship of hemispheric preference,as measured by conjugate lateral eye movements,to accuracy of emotional facial expression

This study investigated the relationship between hemispheric preference and communication accuracy of facial affect. Hemispheric preference was determined by rating conjugate lateral eye movements. Forty right-handed females were classified: 10 right-movers (left hemisphere preference), 15 left-movers (right hemisphere preference), and 15 bidirectionals (no hemispheric preference). Subjects were shown emotionally loaded slides portraying happiness, fear, and disgust and their videotaped facial expressions were independently rated for accuracy. It was predicted that negative emotions involved right hemisphere activity and negative affect involved left hemisphere activity. As expected, it was found that left-movers were significantly better than right-movers at nonverbally communicating disgust and fear; hemispheric preference was unrelated to expression of happiness. The accuracy scores of the bidirectionals generally fell in between those of the left-movers and those of the right-movers. The results were discussed in reference to the differential lateralization of positive and negative emotions.This study was conducted as a senior research project by the first author under the supervision of the second author.