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.     

Body asymmetry affects conjugate lateral eye movement

A. H. Baker (1989) and A. H. Baker and A. I. Ledner (1990) reported that asymmetrical visual stimulation affects conjugate lateral eye movement (CLEM). In the present article, the authors explored whether asymmetrical body position similarly affects CLEM. The authors assessed CLEMs twice in a counterbalanced design. In the control (symmetric) condition, each participant sat in a completely symmetrical position facing a wall devoid of any asymmetrical features. In the experimental (asymmetrical) condition, half the participants rotated their heads 68 degrees clockwise relative to their bodies to face the experimenter, and the other half rotated their heads 68 degrees counterclockwise, also to face the experimenter. CLEM was predominantly toward the body's position in the asymmetrical condition rather than toward the body's position in the symmetrical condition.     

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.     

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.     

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.     

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 handedness and saccadic bilateral eye movements on components of autobiographical recollection

The effects of handedness and saccadic bilateral eye movements on autobiographical recollection were investigated. Recall of autobiographical memories was cued by the use of neutral and emotional words. Autobiographical recollection was assessed by the autobiographical memory questionnaire. Experiment 1 found that mixed-handed (vs. right handed) individuals demonstrated greater levels of autobiographical recollection on the components of seeing, hearing, and emotion. Experiment 2 found that following 30 s of bilateral eye movements, greater levels of autobiographical recollection were demonstrated on the components of reliving, seeing, hearing, emotion, self-perspective and veridicality. The results extend previous research by showing that the recollective components of real world memories can be enhanced by either mixed-handedness or eye movements. In addition, these results provide a bridge between laboratory studies of recollection and autobiographical recollection. The findings are considered in terms of research on the cognitive neuroscience of autobiographical memory.     

Influence of handedness and bilateral eye movements on creativity

We investigated the effects of increased inter-hemispheric interaction (IHI) on five creativity dimensions (appropriateness, detail, categorical distinctiveness, fluency, and originality) of the Alternate Uses Task. Two methods were used to indicate degree of IHI. Trait IHI was indicated by individual differences in handedness, mixed-handers showing greater IHI than strong-handers. State IHI was directly manipulated by central (control group) and bilateral viewing conditions of a 30 s eye movement task (EM). Results indicate significantly higher creativity for mixed-handers, as compared to strong-handers, for all five sub-scores separately and linearly combined. Bilateral EM increased originality and categorical distinctiveness (i.e., flexibility) of strong-handers, but had no effect on mixed-handers. Strong-handers in the bilateral EM group were not different from mixed-handers. Additionally, the bilateral EM effect on strong-handers had different durations for originality (up to 7–9 min) and categorical distinctiveness (up to 3 min). The results suggest that greater IHI can facilitate creativity of strong-handers, but that the characteristically higher IHI of mixed-handers was unaffected by the bilateral EM manipulation.     

Search asymmetry and eye movements in infants and adults

Search asymmetry is characterized by the detection of a feature-present target amidst feature-absent distractors being efficient and unaffected by the number of distractors, whereas detection of a feature-absent target amidst feature-present distractors is typically inefficient and affected by the number of distractors. Although studies have attempted to investigate this phenomenon with infants (e.g., Adler, Inslicht, Rovee-Collier, & Gerhardstein in Infant Behavioral Development, 21, 253–272, 1998; Colombo, Mitchell, Coldren, & Atwater in Journal of Experimental Psychology: Learning, Memory and Cognition, 19, 98–109, 1990), due to methodological limitations, their findings have been unable to definitively establish the development of visual search mechanisms in infants. The present study assessed eye movements as a means to examine an asymmetry in responding to feature-present versus feature-absent targets in 3-month-olds, relative to adults. Saccade latencies to localize a target (or a distractor, as in the homogeneous conditions) were measured as infants and adults randomly viewed feature-present (R among Ps), feature-absent (P among Rs), and homogeneous (either all Rs or all Ps) arrays at set sizes of 1, 3, 5, and 8. Results indicated that neither infants’ nor adults’ saccade latencies to localize the target in the feature-present arrays were affected by increasing set sizes, suggesting that localization of the target was efficient. In contrast, saccade latencies to localize the target in the feature-absent arrays increased with increasing set sizes for both infants and adults, suggesting an inefficient localization. These findings indicate that infants exhibit an asymmetry consistent with that found with adults, providing support for functional bottom-up selective attention mechanisms in early infancy.     

The impact of eye movements on a verbal creativity task

Bilateral eye movements (EMs) have been shown to induce cognitive enhancements for episodic memory, attention, and divergent thinking. Increased interhemispheric interaction has been suggested as a possible mechanism behind the EM effect, but other theories, including an increase in attentional control following EMs have also been proposed. The present research explored whether the bilateral EM effect could be extended to a creativity task that draws heavily on convergent thinking. Participants were randomly assigned to one of four EM conditions (bilateral, centre control, right-centre, or left-centre) and were presented with compound remote associate problems. After 7 s, participants were asked to make a solution/non-solution judgement to a target word presented in the left or right visual field. Bilateral and right-centre EM conditions exhibited enhanced performance on the task, with the bilateral condition demonstrating the best performance for solution targets and the right-centre condition presenting the best performance for non-solution targets. The implications of these findings are discussed in light of the neural components of creativity and theories surrounding the effects of EMs on cognition.     

Effects of saccadic bilateral eye movements on memory in children and adults: an exploratory study

The effects of saccadic bilateral (horizontal) eye movements on true and false memory in adults and children were investigated. Both adults and children encoded lists of associated words in the Deese-Roediger-McDermott paradigm followed by a test of recognition memory. Just prior to retrieval, participants were asked to engage in 30s of bilateral vs. vertical vs. no eye movements. For studied information, the results for adults replicated previous work; bilateral eye movements were demonstrated to increase the accuracy of memory by increasing the hit rate and reducing the false alarm rate for related and unrelated recognition test lures. The results for children also indicated an improvement in memory accuracy, and like adults, was due to both an increase in the hit rate and a reduction in the false alarm rate. In spite of these similarities, the effects of bilateral eye movements differed between adults and children for critical unstudied words; i.e., those associated with the theme of the list. Only in adults did, bilateral eye movements reduce associative false memories; children did not show a reduction in false memory for critical associates. This produced a dissociation between the effects of eye movements on associative false memory as a function of age. The results are discussed from a developmental perspective in terms of potential mechanisms underlying true and false memory.     

Human movement-related brain potentials preceding voluntary movements in different arousal states monitored with skin potential level

The present study investigated the readiness potential (RP) preceding a brisk extension of the right middle finger during different arousal states as monitored by skin potential level (SPL). The late component of the readiness potential in the medium arousal state was significantly larger than those in the low and high arousal states. This finding indicates that the RP waveform may vary as a function of arousal states, suggesting the inverse U-shaped relationship proposed in studies of the contingent negative variation.     

The left: lateral eye movements and ideology.

The lateral eye movements of 24 college students were videotaped as they reflected on spatial and analytical questions. As predicted, participants with more initial movements to the left had significantly higher scores on the leftist (or humanistic) index of the Tomkin's Polarity Scale. The direction of this relationship was reversed for the rightist index (right movers scoring higher) but this difference was not significant. Results are interpreted as additions to evidence which suggests a connection between the left and right sides of the human body and more global dichotomies of ideology or personality.     

An asymmetry in the control of eye movements and shifts of attention

Under conditions of monocular viewing, eye movements tend to be directed toward stimuli in the temporal visual field. The present experiments indicate that this bias does not extend to shifts of attention under conditions in which the eyes remain fixed. Experiments 1 and 2 support this conclusion for voluntary shifts of attention, experiment 3 for involuntary shifts of attention. These results support Posner and Cohen's (1980) hypothesis that the temporal bias reflects the properties of an isolable component of the eye movement control system and extend previous dissociations of the mechanisms underlying the control of shifts of attention and eye movements.     

Rightward superiority of eye movements in a bimanual aiming task

To examine the role of visual monitoring in the between-hand differences in skilled manual movements, eye movements and performance during bimanual aiming tasks were analysed. When subjects were required to make bimanual aiming responses to symmetrically placed targets, they preferentially monitored the movements of the right hand, resulting in better performance on the right hand. In addition, manipulation of the subject's gaze showed that the movements of the right hand were more influenced by visual monitoring than those of the left hand. The results were interpreted as showing that the between-hand differences in skilled movements are mainly due to the different efficiency in the use of visual monitoring.     

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.     

Effects of thematic and lexical priming on readers' eye movements

The study was inspired by Ehrlich & Rayner (1981). In the study semantic context effects were investigated during on-line discourse processing. Readers' eye movements were registered to see whether words that were semantically closely related to the global theme of the text were read faster than words that did not have any apparent semantic link to the discourse theme. In addition, lexical priming was examined by presenting an identity prime earlier in the text. The results showed that non-thematic words were regressed to more often than thematic words. Regressions were typically initiated after reaching a clause or sentence boundary. Regressions were thus assumed to be made in order to integrate non-thematic words into the previous context. Modest negative correlations were found between word's fixation time and its relative predictability. No effects of lexical priming were observed. It was concluded that moderately constraining discourse contexts produce negligible effects on word recognition.     

Effects of syntactic prominence on eye movements during reading

Three experiments explored whether patterns of eye movements during reading might help explain syntactic prominence effects that are typically observed using reaction time tasks. Participants read sentences in which target words were in syntactically prominent or syntactically less prominent positions. Across all three experiments, using three types of syntactic prominence manipulations, there were fewer fixations and shorter reading times for words in more prominent positions, indicating that enhanced accessibility of syntactically prominent words is not caused by increased processing time. Rather, syntactic prominence appears to facilitate early encoding/lexical access and sentence integration processes while also, as shown previously, increasing activation of concepts in a comprehender’s sentence or discourse representation. We propose that enhanced encoding and sentence integration processes can be attributed to an increase in attentional resources for more prominent concepts, and that this increase derives from readers’ immediate sensitivity to informational prominence contours that are signaled by syntax.