The relationship between eye position and egocentric visual direction.

Hering's model of egocentric visual direction assumes implicitly that the effect of eye position on direction is both linear and equal for the two eyes; these two assumptions were evaluated in the present experiment. Five subjects pointed (open-loop) to the apparent direction of a target seen under conditions in which the position of one eye was systematically varied while the position of the other eye was held constant. The data were analyzed through examination of the relationship between the variations in perceived egocentric direction and variations in expected egocentric direction based on the positions of the varying eye. The data revealed that the relationship between eye position and egocentric direction is indeed linear. Further, the data showed that, for some subjects, variations in the positions of the two eyes do not have equal effects on egocentric direction. Both the between-eye differences and the linear relationship may be understood in terms of individual differences in the location of the cyclopean eye, an unequal weighting of the positions of the eyes in the processing of egocentric direction, or some combination of these two factors.     

The influence of eye movements and eye position on perception of the visual vertical

Summary Four experiments are reported which involved the adjustment of two points of light in an otherwise dark room to the visual vertical. In the first two experiments different point separations (corresponding to visual angles of about 2° and 23°) were employed in an attempt to control the degree of scanning eye movements. Binocular adjustments to the visual vertical during body tilt were influenced by the point separation (Exp. 1), but monocular adjustments with the head upright were not (Exp. 2). Using the larger point separation and fixating the top point the visual vertical using the right eye was counterclockwise of that with fixation of the bottom point when the head was upright (Exp. 3), but this difference was not found for judgments during tilt (Exp. 4). The results were discussed in terms of the rotational changes in eye position accompanying scanning eye movements and ocular elevation and depression.

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Zusammenfassung Es wird über vier Experimente berichtet, in denen es um die Einstellungen zweier Lichtpunkte in eine vertikale Richtung geht. In den ersten zwei Experimenten sollte der Einfluß der Fixierbewegungen der Augen geprüft werden. Der Winkelabstand der Lichtpunkte betrug 2° oder 23°. Bei seitwärts geneigtem Körper und binokularer Betrachtung wurde ein Unterschied gefunden (Exp. 1). Bei aufrecht gehaltenem Kopf und monokularer Betrachtung dagegen zeigte sich kein Unterschied (Exp. 2). Wurde in aufrechter Körperlage und bei einem Punktabstand von 23° der obere Punkt mit dem rechten Auge fixiert, so verschob sich die scheinbare Vertikale im Uhrzeigersinn; sie verschob sich noch weiter im Uhrzeigersinn, wenn der untere Punkt fixiert wurde (Exp. 3). Bei geneigtem Körper wurde dagegen kein Unterschied festgestellt (Exp. 4). Die Ergebnisse werden im Zusammenhang mit der Augendrehung diskutiert, die mit dem scanning sowie mit der Auf- und Abbewegung der Augen beim Fixieren verbunden ist.

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This research was carried out while I was a recipient of a Forschungsstipendium from the Alexander von Humboldt-Stiftung, appreciation for which is gratefully acknowledged. I also wish to thank the subjects who participated in the experiments.     

The cyclopean eye vs. the sighting-dominant eye as the center of visual direction

In three experiments, competing hypotheses concerning the center of visual direction were examined with the stimuli used in the Card test which requires a subject to position the card with a hole so that a target can be seen. Each experiment used six right- and six left-sighting-eye subjects. In Experiment 1, the aperture and the target were collinear with the sighting eye. The mean apparent locations of the aperture when the target was fixated, and of the target when the aperture was fixated, were consistent with only the cyclopean-eye hypothesis; that is, the 95% confidence intervals of these means contained the predicted values from the cyclopean-eye hypothesis but not those from the sighting-eye hypothesis. In Experiment 2, subjects moved the card from the side of the nonsighting eye, and in 88% of the trials it was stopped when the nonsighting eye viewed the target. In Experiment 3, the target was viewed through the aperture with both the sighting and nonsighting eye in six different stimulus arrangements. The 95% confidence intervals of all 12 mean apparent locations of the targets contained the predicted values from the cyclopean-eye hypothesis but none of those from the sighting-eye hypothesis. These results are compatible with the cyclopean-eye hypothesis, and we therefore conclude that the sighting eye is not the center of visual direction.     

Eye position and visual attention influence perceived auditory direction

The singular and joint effects of eccentric visual fixation and peripheral visual attention upon the perceived auditory median plane (PAMP) of the head were examined in four subjects. They positioned a hidden, horizontally-moving sound source to the perceived median plane of the head, while fixating a light 20 degrees or 45 degrees to the right or left of the actual median plane, and attending to another light in peripheral vision. Analysis by multiple linear regression yielded a model for each subject which indicated the nature and weighting of those factors contributing to variance reduction in PAMP judgments. Three subjects showed a strong linear attention effect, resulting in shifts of the PAMP away from the locus of attention. Similarly, a strong linear fixation effect was discovered in two subjects, a weak effect in another, and a nonlinear, inverse fixation effect in the last. Additional factors were noted for some subjects. Possible explanations of the observed effects were discussed. The study indicates that both visual attention and visual fixation are critical factors in experiments on auditory space perception although inter-individual differences do exist in the nature and strength of the effects.     

The egocentric reference for visual exploration and orientation

Clinical signs of damage to the egocentric reference system range from the inability to detect stimuli in the real environment to a defect in recovering items from an internal representation. Despite clinical dissociations, current interpretations consider all symptoms as due to a single perturbation, differentially expressed according to the medium explored (perceptual or representational). We propose an alternative account based on the functional distinction between two separate egocentric mechanisms: one allowing construction of the immediate point of view, the other extracting a required perspective within a mental representation. Support to this claim comes from recent results in the domain of navigation, showing that separate cognitive mechanisms maintain the egocentric reference when actively exploring the visual space as opposed to moving according to an internal map. These mechanisms likely follow separate developmental pathways, seemingly depend on distinct neural pathways and are used independently by healthy adults, reflecting task demands and individual cognitive style. Implications for spatial cognition and social skills are discussed.     

视觉观点采择中自我中心性偏差的抑制和归因之争

自我中心性偏差是社交失败的重要原因,但其产生机制还存在争议。以往研究存在抑制性选择模型与流利性错误归因两种理论观点:前者认为对自身观点的抑制失败会导致自我中心性偏差;后者则认为错误地选择自身更为流畅的信息会导致自我中心性偏差。为整合上述争论,提出抑制-归因协同作用模型,认为抑制和归因两种加工或可共同导致自我中心性偏差。未来研究应借助精巧的研究范式和特殊被试群体,进一步验证该模型。     

Gaze direction and the extraction of egocentric distance

The angular declination of a target with respect to eye level is known to be an important cue to egocentric distance when objects are viewed or can be assumed to be resting on the ground. When targets are fixated, angular declination and the direction of the gaze with respect to eye level have the same objective value. However, any situation that limits the time available to shift gaze could leave to-be-localized objects outside the fovea, and, in these cases, the objective values would differ. Nevertheless, angular declination and gaze declination are often conflated, and the role for retinal eccentricity in egocentric distance judgments is unknown. We report two experiments demonstrating that gaze declination is sufficient to support judgments of distance, even when extraretinal signals are all that are provided by the stimulus and task environment. Additional experiments showed no accuracy costs for extrafoveally viewed targets and no systematic impact of foveal or peripheral biases, although a drop in precision was observed for the most retinally eccentric targets. The results demonstrate the remarkable utility of target direction, relative to eye level, for judging distance (signaled by angular declination and/or gaze declination) and are consonant with the idea that detection of the target is sufficient to capitalize on the angular declination of floor-level targets (regardless of the direction of gaze).     

The changing relationship between psychology and contemporary spiritual direction

As recently as the late 1970's, the relationship between spiritual direction and psychology was tentative and cautious. During the last decade, however, psychological methods and perspectives have been increasingly utilized in spiritual direction. This article examines how clinical psychology, developmental psychology, the psychology of women, and professional psychology are becoming increasingly relevant to the contemporary practice of spiritual direction in the United States, and how, in the process, the relationship between psychology and spiritual direction is changing.     

气质与眼动控制的关系

本研究采用眼动追踪和问卷测量相结合的方法,对气质类型和眼动控制的关系进行了探讨。眼动实验为2（眼跳方向：朝向眼跳和反向眼跳）X 2（任务类型：重复眼跳和转换眼跳）组内设计;气质分数用陈会昌编制的《气质类型测试量表》测量。结果表明,气质分数与眼动特性之间存在显著的相关性,不同气质类型（神经活动类型）在抑制过程和任务重置过程中表现出不同的相互作用模式。具体而言,神经活动强度是一个基本维度,它与认知控制的抑制功能和转换功能都有着密切联系;而神经活动的灵活性和平衡性则分别是转换功能和抑制功能的重要条件。     

The relationship between eye movements and spatial attention

Most previous studies of the attentional consequences of making saccadic eye movements have used peripheral stimuli to elicit eye movements. It is argued that in the light of evidence showing automatic “capture” of attention by peripheral stimuli, these experiments do not distinguish between attentional effects due to peripheral stimuli and those due to eye movements. In the present study, spatial attention was manipulated by varying the probability that peripheral probe stimuli would appear in different positions, while saccades were directed by a central arrow, enabling the effects of attention and eye movements to be separated. The results showed that the time to react to a peripheral stimulus could be shortened both by advance knowledge of its likely position and, separately, by preparing to make a saccade to that position. When the saccade was directed away from the most likely position of the probe, the targets for attention and eye movements were on opposite sides of the display. In this condition, the effects of preparing to make a saccade proved to be stronger than the effects of attentional allocation until well after the saccade had finished, suggesting that making a saccade necessarily involves the allocation of attention to the target position. The effects of probe stimuli on saccade latencies were also examined: probe stimuli that appeared before the saccade shortened saccade latencies if they appeared at the saccade target, and lengthened saccade latencies if they appeared on the opposite side of fixation. These facilitatory and inhibitory effects were shown to occur at different stages of saccade preparation and suggest that attention plays an important role in the generation of voluntary eye movements. The results of this study indicate that while it is possible to make attention movements without making corresponding eye movements, it is not possible to make an eye movement (in the absence of peripheral stimulation) without making a corresponding shift in the focus of attention.     

The relationship between allocentric and egocentric frames of reference and categorical and coordinate spatial information processing

We report two experiments on the relationship between allocentric/egocentric frames of reference and categorical/coordinate spatial relations. Jager and Postma (2003) suggest two theoretical possibilities about their relationship: categorical judgements are better when combined with an allocentric reference frame and coordinate judgements with an egocentric reference frame (interaction hypothesis); allocentric/egocentric and categorical/coordinate form independent dimensions (independence hypothesis). Participants saw stimuli comprising two vertical bars (targets), one above and the other below a horizontal bar. They had to judge whether the targets appeared on the same side (categorical) or at the same distance (coordinate) with respect either to their body-midline (egocentric) or to the centre of the horizontal bar (allocentric). The results from Experiment 1 showed a facilitation in the allocentric and categorical conditions. In line with the independence hypothesis, no interaction effect emerged. To see whether the results were affected by the visual salience of the stimuli, in Experiment 2 the luminance of the horizontal bar was reduced. As a consequence, a significant interaction effect emerged indicating that categorical judgements were more accurate than coordinate ones, and especially so in the allocentric condition. Furthermore, egocentric judgements were as accurate as allocentric ones with a specific improvement when combined with coordinate spatial relations. The data from Experiment 2 showed that the visual salience of stimuli affected the relationship between allocentric/egocentric and categorical/coordinate dimensions. This suggests that the emergence of a selective interaction between the two dimensions may be modulated by the characteristics of the task.     

On-court position and handedness in visual anticipation of stroke direction in tennis

ObjectivesIn racket sports, players integrate information picked up from their opponent's kinematics and contextual cues like on-court position into shot outcome anticipation. In view of suggested difficulties with anticipating left-handed opponents' action intentions, here we examined whether an opponent's handedness interacts with position-dependency in visual anticipation.Design and methodFollowing a 2 (Group) x 2 (Handedness) x 2 (Position) x 3 (Temporal Occlusion) factorial design, 20 tennis players and 20 non-players predicted directional outcome of temporally manipulated point-light animations of identical left- and right-handed forehand groundstrokes performed near vs. far from the court's midline.ResultsTennis players' response selection was mostly affected by an opponent's on-court position, particularly at an early stage of a hitting movement. Opponents' handedness affected response selection similarly in both groups (i.e., bias towards down-the-line predictions against left-handed strokes occluded at racket-ball-contact), but it did not interact with on-court position.ConclusionsFindings highlight that on-court position, and opponents' handedness to some extent as well, appears relevant for skilled visual anticipation in tennis.     

Hiding and finding: The relationship between visual concealment and visual search

As an initial step toward developing a theory of visual concealment, we assessed whether people would use factors known to influence visual search difficulty when the degree of concealment of objects among distractors was varied. In Experiment 1, participants arranged search objects (shapes, emotional faces, and graphemes) to create displays in which the targets were in plain sight but were either easy or hard to find. Analyses of easy and hard displays created during Experiment 1 revealed that the participants reliably used factors known to influence search difficulty (e.g., eccentricity, target—distractor similarity, presence/absence of a feature) to vary the difficulty of search across displays. In Experiment 2, a new participant group searched for the targets in the displays created by the participants in Experiment 1. Results indicated that search was more difficult in the hard than in the easy condition. In Experiments 3 and 4, participants used presence versus absence of a feature to vary search difficulty with several novel stimulus sets. Taken together, the results reveal a close link between the factors that govern concealment and the factors known to influence search difficulty, suggesting that a visual search theory can be extended to form the basis of a theory of visual concealment.     

The relationship between allocentric and egocentric frames of reference and categorical and coordinate spatial information processing

We report two experiments on the relationship between allocentric/egocentric frames of reference and categorical/coordinate spatial relations. Jager and Postma (2003) suggest two theoretical possibilities about their relationship: categorical judgements are better when combined with an allocentric reference frame and coordinate judgements with an egocentric reference frame (interaction hypothesis); allocentric/egocentric and categorical/coordinate form independent dimensions (independence hypothesis). Participants saw stimuli comprising two vertical bars (targets), one above and the other below a horizontal bar. They had to judge whether the targets appeared on the same side (categorical) or at the same distance (coordinate) with respect either to their body-midline (egocentric) or to the centre of the horizontal bar (allocentric). The results from Experiment 1 showed a facilitation in the allocentric and categorical conditions. In line with the independence hypothesis, no interaction effect emerged. To see whether the results were affected by the visual salience of the stimuli, in Experiment 2 the luminance of the horizontal bar was reduced. As a consequence, a significant interaction effect emerged indicating that categorical judgements were more accurate than coordinate ones, and especially so in the allocentric condition. Furthermore, egocentric judgements were as accurate as allocentric ones with a specific improvement when combined with coordinate spatial relations. The data from Experiment 2 showed that the visual salience of stimuli affected the relationship between allocentric/egocentric and categorical/coordinate dimensions. This suggests that the emergence of a selective interaction between the two dimensions may be modulated by the characteristics of the task.     

Correlation between the position of the egocentric reference and right neglect signs in left-brain-damaged patients

Fourteen control subjects and thirty left-brain-damaged (LBD) patients with or without neglect performed a straight-ahead pointing task with their left hand while blindfolded. Results showed a significant correlation between the position of the egocentric reference and the presence of right neglect signs. We discuss here the egocentric hypotheses of spatial bias.     

The relationship between visual attention and expertise in sports

ObjectivesGiven the prevalence of misperception and failed perception, particularly in attention-demanding team sports, surprisingly few studies have explored whether experts in team sports differ from other athletes and from non-athletes in their basic attention abilities.MethodIn this study, we examined group differences between experts in team handball (n = 40), athletes from non-team sports (n = 40), and novice athletes (n = 40) using a battery of three attention tasks: a functional field of view task, a multiple-object tracking task, and an inattentional blindness task.ResultsPerformance on the three attention tasks was largely independent, with no significant correlations among the tasks. Team sports experts showed no better performance on the basic attention tasks than did athletes from non-teams sports or novice athletes.ConclusionsThe finding that all basic attention tasks are largely independent provides preliminary support for the idea that attentional breadth, tracking performance, and inattentional blindness are distinct attentional processes. Our results demonstrate that sports expertise effects are unrelated to basic differences in attention—expertise does not appear to produce differences in basic attention and basic differences in attention do not appear to predict eventual expertise. Further experiments could focus on the ways in which more specific attentional strategies and processes contribute to sports performance.     

The relation between hiding skill and judgment of eye direction in preschool children

This study examines J. H. Flavell, S. G. Shipstead, and K. Croft's (1978) finding that 2 1/2-year-old children can hide an object behind a screen but cannot achieve the same result by placing the screen in front of the object. Experiment 1 replicated this finding alongside a task in which children judged what a person in a picture was looking at. Performance on the move-object task approached ceiling; performances on the move-screen and looking-where tasks were highly correlated even after age and control task performance were partialed out (r = .54, p < .01). Experiment 2 examined whether the finding resulted because the object was more interesting to manipulate than the screen. The move-object task remained easier than the move-screen task with an interesting screen and a dull object. The move-screen task again correlated specifically with the looking-where task. Results are explained in terms of engagement, a precursor to a mature understanding of attention.