Relationship between visual orientation and susceptibility to motion sickness.

24 male subjects were divided into 3 groups, on the basis of their susceptibility to motion sickness. All subjects were then required to set a luminous line in an apparently vertical position while viewing the line from a body position which was deviated 70 degrees laterally from the upright. No visible frame of reference was available. A significant relationship between motion sickness susceptibility and errors in judging the vertical was discovered, the "intermediate" susceptibility group making the greatest errors. The role of the vestibular system in visual orientation and motion sickness is discussed. The result also indicates the potential value of using perceptual performance as a tool in the study of motion sickness and its correlates.     

Stress sensitive healthy females show less left amygdala activation in response to withdrawal-related visual stimuli under passive viewing conditions

The amygdalae are key players in the processing of a variety of emotional stimuli. Especially aversive visual stimuli have been reported to attract attention and activate the amygdalae. However, as it has been argued that passively viewing withdrawal-related images could attenuate instead of activate amygdalae neuronal responses, its role under passive viewing conditions remains unclear. Furthermore, because individual sensitivity to stress reactions has been shown to modulate amygdalae processing, the aim of the current event-related fMRI study was to investigate whether individual differences in stress proneness could influence amygdala responses while passively viewing withdrawal and approach-related visual images. We presented 14 healthy female subjects with a random sequence of images of happy 'healthy' baby faces (approach-related) and baby faces disfigured by severe dermatological conditions (withdrawal-related). No instructions were given other than to watch the images attentively. We integrated individual perceived stress (PSS) scores in our analysis. The processing of withdrawal-related pictures resulted in less left amygdala activity in females scoring higher on perceived stress. Our findings suggest that stress-sensitive healthy females are less able to fully attend to withdrawal-related visual material and in essence avoid exposure to such images in an effort to reduce strong psychophysiological responses. Although the relatively small number of participants limits drawing firm conclusions, we suggest that in passive viewing emotional brain imaging paradigms, individual information on stress proneness should be included in the interpretation of amygdala neuronal processes.     

Relationship between perceptual style and ability to reproduce a standard work task

The present study examined the relationship between perceptual style and perception of physical effort. Perceptual style of 10 men and 10 women was assessed by the rod-and-frame apparatus. Perception of physical effort was defined as the difference in heart-rate responses between a standard work task and the subject's self-selected task. Heart-rate response on the pre-selected standard work task on a cycle ergometer (600 kpm.min.-1) was extremely variable, ranging from 111 to 188 beats per minute (M = 153 +/- 23.5). However, average error between heart rate during the standard work task and the subjects' self-adjusted workload was extremely low (range 0 to 18 beats per minute; M = 5.4 +/- 5.5 beats per minute). Pearson correlation of .78 showed a moderate relationship between heart rate and rating of perceived effort, but was nonsignificant (-.12) between perceptual style and perception of physical effort. The data confirm the absence of a significant relationship between perceptual style (i.e., field dependence-independence) and ability to reproduce a standard work task. In addition, these results suggest that there has been possible bias in studies of relationships between heart rate and rating of perceived effort or workload and rating of perceived effort during incremental testing.     

Intelligence and susceptibility to persuasion under conditions of active and passive participation

An experiment was conducted to test the prediction that verbal intelligence facilitates opinion change induced by active participation (improvising arguments). Seventy-one subjects were randomly assigned to improvise arguments or read persuasive messages advocating the same point of view (passive, control condition) about one of three topics. A short test of verbal intelligence was administered during the experiment; also, American College Test scores were obtained from the files of all subjects for whom they were available. Analysis of variance (with subjects partitioned into high and low intelligence groups) and correlational analyses supported the above prediction. There was some evidence that quality of the arguments improvised mediated the relationship between intelligence and opinion change, but the results were not totally consistent.     

The boundary conditions of priming of visual search: From passive viewing through task-relevant working memory load

Priming of visual search has a dominating effect upon attentional shifts and is thought to play a decisive role in visual stability. Despite this importance, the nature of the memory underlying priming remains controversial. To understand more fully the necessary conditions for priming, we contrasted passive versus active viewing of visual search arrays. There was no priming from passive viewing of search arrays, while it was strong for active search of the same displays. Displays requiring no search resulted in no priming, again showing that search is needed for priming to occur. Finally, we introduced working memory load during visual search in an effort to disrupt priming. The memorized items had either the same colors as or different colors from the visual search items. Retaining items in working memory inhibited priming of the working memory task-relevant colors, while little interference was observed for unrelated colors. The picture that emerges of priming is that it requires active attentional processing of the search items in addition to the operation of visual working memory, where the task relevance of the working memory load plays a key role.     

Adaptation to optically-increased interocular separation under naturalistic viewing conditions

Mirror spectacles which enhance binocular disparity by optically doubling the normal separation between the eyes were used to create conditions of combined perceptual and oculomotor conflict. Apparent depth and distance, as well as tonic accommodation, tonic vergence, and accommodative-vergence gain (response AC/A ratio), were assessed immediately before and after a 30 min exposure period of naturalistic viewing with the spectacles. Wearing the spectacles produced an increase in tonic vergence, and perceptual aftereffects consisting of increased apparent distance and depth. The results indicate that oculomotor conflict associated with enhanced interocular separation may be resolved through adaptation of tonic vergence, rather than through alteration of accommodative-vergence gain. The results also demonstrate that perceptual conflict between disparity and multiple veridical depth cues does not necessarily produce adaptive modification of the relationship between binocular disparity and apparent depth.     

Distance perception under binocular and monocular viewing conditions

First, third, and fifth graders and college adults made judgments of absolute distance in a binocular (full-information) condition and in one of three monocular conditions: redundant texture gradient, compression gradient, and control (no texture). No age-related differences in accuracy of judgment were observed in any of the conditions. Substantial differences in the effectiveness of different kinds of information were found, however. The results indicate that the ability to register information for distance is well developed by first grade, but that substantial limitations exist on the visual system’s ability to process various forms of redundant information.     

Perceptual weight judgments when viewing one's own and others' movements under minimalist conditions of visual presentation

Across five experiments, we investigated the parameters involved in the observation and in the execution of the action of lifting an object. The observers were shown minimal information on movements, consisting of either the working-point displacement only (ie two points representing the hand and object) or additional configural information on the kinematics of the trunk, shoulder, arm, forearm, and hand, joined by a stick diagram. Furthermore, displays showed either a participant's own movements or those of another person, when different weights were lifted. The participants' task was to estimate the weight of the lifted objects. The results revealed that, although overall performance was not dependent on the visual conditions (working point versus stick diagram) or ownership conditions (self versus other), the kinematic cues used to perform the task differed as a function of these conditions. In addition, the kinematic parameters relevant for action observation did not match those relevant for action execution. This was confirmed in experiments by using artificially altered movement samples, where the variations in critical kinematic variables were manipulated separately or in combination. We discuss the implications of these results for the roles of motor simulation and visual analysis in action observation.     

Geometrical illusions in solid objects under ordinary viewing conditions.

The Müller-Lyer and Ponzo illusions were obtained under free binocular viewing of three-dimensional objects, and the function relating magnitude of illusion to fin angle, characteristic of converging-line versions of the Müller-Lyer pattern, was closely paralleled by volumetric (three-cone), line-free objects (but not with an erect, planar "walk-through" construction and moving observers). Illusions cannot be dismissed as artifacts of static, impoverished viewing, therefore, but must be explained within any general theory of perception. Perspective explanations have difficulties with such three-dimensional manifestations, and seem completely inapplicable to our further finding that approximately the same amount of illusion occurred in objects and patterns with no oblique lines or edges. Confusion or averaging theories, not themselves tested here, remain unthreatened by these data.     

Relationship between cognitive style and emotional behavior.

In this research we examined the relationships among cognitive styles using the categorization of Bion and styles of modulation of emotional behavior (hostile content) explored with the Gottschalk, et al. method applied to the speech of 20 female and 10 male undergraduate students whose ages ranged from 20 to 35 years. Their verbalization was produced in a standard stimulus situation of 3 minutes duration. Analysis indicated a relationship between hostile attitude and cognitive styles. In particular, those who were relatively less hostile presented higher frequencies of processes classified by Bion as D2, which are characterized by an attitude of expectancy and waiting, with a tendency to defend internal psychological themas.     

Influence of semantic consistency and perceptual features on visual attention during scene viewing in toddlers

Conceptual representations of everyday scenes are built in interaction with visual environment and these representations guide our visual attention. Perceptual features and object-scene semantic consistency have been found to attract our attention during scene exploration. The present study examined how visual attention in 24-month-old toddlers is attracted by semantic violations and how perceptual features (i. e. saliency, centre distance, clutter and object size) and linguistic properties (i. e. object label frequency and label length) affect gaze distribution. We compared eye movements of 24-month-old toddlers and adults while exploring everyday scenes which either contained an inconsistent (e.g., soap on a breakfast table) or consistent (e.g., soap in a bathroom) object. Perceptual features such as saliency, centre distance and clutter of the scene affected looking times in the toddler group during the whole viewing time whereas looking times in adults were affected only by centre distance during the early viewing time. Adults looked longer to inconsistent than consistent objects either if the objects had a high or a low saliency. In contrast, toddlers presented semantic consistency effect only when objects were highly salient. Additionally, toddlers with lower vocabulary skills looked longer to inconsistent objects while toddlers with higher vocabulary skills look equally long to both consistent and inconsistent objects. Our results indicate that 24-month-old children use scene context to guide visual attention when exploring the visual environment. However, perceptual features have a stronger influence in eye movement guidance in toddlers than in adults. Our results also indicate that language skills influence cognitive but not perceptual guidance of eye movements during scene perception in toddlers.     

Aiming at a far target under different viewing conditions: visual control in basketball jump shooting

Most research on visual search in aiming at far targets assumes preprogrammed motor control implying that relevant visual information is detected prior to the final shooting or throwing movements. Eye movement data indirectly support this claim for stationary tasks. Using the basketball jump shot as experimental task we investigated whether in dynamic tasks in which the target can be seen until ball release, continuous, instead of preprogrammed, motor control is possible. We tested this with the temporal occlusion paradigm: 10 expert shooters took shots under four viewing conditions, namely, no vision, full vision, early vision (vision occluded during the final +/-350 ms before ball release), and late vision (vision occluded until these final +/-350 ms). Late-vision shooting appeared to be as good as shooting with full vision while early-vision performance was severely impaired. The results imply that the final shooting movements were controlled by continuous detection and use of visual information until ball release. The data further suggest that visual and movement control of aiming at a far target develop in close correspondence with the style of execution.     

Size and distance judgments under reduced conditions of viewing

Magnitude estimations of the size and distance of a variable relative to a standard were obtained in the absence of distance cues. Estimates were provided by different groups under three conditions: (a) physical size and distance variant, visual angle of the variable constant and equal to the standard, (b) physical size constant, physical distance and visual angle of variable changing, and (c) physical distance constant, physical size and visual angle of the variable changing. The results in both experiments were very similar. In each case both size and distance estimates conformed to relative visual angle. The results are applied to an analysis of size-matches that are obtained when distance cues are eliminated.     

Relationship between coping styles and perceptual asymmetry

This study examined the relationship between coping styles and hemispheric asymmetry, on the basis of prior evidence of reduced posterior right hemisphere (RH) activity in depression, and the relationship between ruminative coping and depression. Two samples of undergraduates (N = 170) completed chimeric faces tasks and 2 measures of coping styles, the self-report Responses Styles Questionnaire and a behavioral choice task. In women but not in men, self-reported rumination was associated with a decreased RH bias on the emotion-based chimeric task. In both genders, choosing to engage in an emotional task was associated with increased RH involvement. Results indicate that although brooding and dwelling on the negative may be associated with decreased RH involvement, openness to emotion may be associated with increased RH involvement.     

Blood pressure reactivity to active and passive behavioral conditions in hypertensives and normotensives

Blood pressure reactivity and passive behavioral tasks was studied in patients with mild essential hypertension and normotensive controls. The passive condition included 10 presentations of a 6 sec, 78 dB, 1000 Hz tone without any response requirements. In the active condition subjects were given an additional 10 tone presentations and asked to press a push-button at tone termination. The absolute and percent increase in systolic blood pressure from rest was greater in hypertensives than normotensives in response to the active condition but similar to the passive condition. It is concluded that patients with hypertension compared to normotensive controls show exaggerated blood pressure reactivity to tasks involving active but not passive coping efforts. Since the tasks used to induce active and passive coping in the present study were identical apart from coping requirements, the notion that the activity dimension in and of itself modulates reactivity differences between patients and controls is supported.     

Role of familiar size in spatial judgments under natural viewing conditions.

The purpose of the present experiment was to examine the role of familiar size in judgments of size and egocentric distance under natural (non-reduced) viewing conditions. Independent groups (ns = 14) judged normal and large off-size chairs and control objects presented at a distance of 25.6 m. Subjects also judged the size of unfamiliar objects (adjacent stimuli) attached to the chairs and stakes. The results indicate that the effects of familiar size are specific to spatial judgments of the familiar object itself since judgments of the adjacent stimuli were unaffected by familiar size.