Visual perception during naturalistic near-death out-of-body experiences

This study attempted to ascertain the most appropriate content and placement of visual stimuli in a hospital-based study of the veridicality of out-of-body perception in the near-death experience (NDE), and the likelihood that a subject in such a study would notice, clearly perceive, and accurately recall a visual stimulus. Based on the questionnaire responses of 63 subjects who had near-death out-of-body experiences (ND OBEs), at least some of the respondents described sufficiently complete and accurate visual perception during the experience to warrant the pursuit of veridicality research in hospitals. Recommended stimulus content for such research includes a surface with intense color and lighting, and simple number and/or letter combinations. Stimuli should be as far below ceiling level as possible while maintaining double-blind criteria. Some characteristics of the individual NDE and NDEr may affect veridical perception during the ND OBE.This paper was derived in part from her Ed.D. dissertation submitted to the Northern Illinois University Graduate School.     

How Are Different Properties of a Scene Encoded in Visual Memory?

Recent studies in scene perception suggest that much of what observers believe they see is not retained in visual memory. Depending on the roles they play in organizing the perception of a scene, different visual properties may require different amounts of attention to be incorporated into a mental representation of the scene. The goal of this study was to compare how three visual properties of scenes, colour, object position, and object presence, are encoded in visual memory. We used a variation on the change detection “flicker” task and measured the time to detect scene changes when: (1) a cue was provided regarding the type of change; and, (2) no cue was provided. We hypothesized that cueing would enhance the processing of visual properties that require more attention to be encoded into scene representations, whereas cueing would not have an effect for properties that are readily or automatically encoded in visual memory. In Experiment 1, we found that there was a cueing advantage for colour changes, but not for position or presence changes. In Experiment 2, we found the same cueing effect regardless of whether the colour change altered the configuration of the scene or not. These results are consistent with the idea that properties that typically help determine the configuration of the scene, for example, position and presence, are better encoded in scene representations than are surface properties such as colour.     

Use of rhythm in acquisition of a computer-generated tracking task.

This research assessed whether rhythm aids acquisition of motor skills by providing cues for the timing of those skills. Rhythms were presented to participants visually or visually with auditory cues. It was hypothesized that the auditory cues would facilitate recognition and learning of the rhythms. The three timing principles of rhythms were also explored. It was hypothesized that rhythms that satisfied all three timing principles would be more beneficial in learning a skill than rhythms that did not satisfy the principles. Three groups learned three different rhythms by practicing a tracking task. After training, participants attempted to reproduce the tracks from memory. Results suggest that rhythms do help in learning motor skills but different sets of timing principles explain perception of rhythm in different modalities.     

Relative cues and absolute distance perception

It is possible, in theory, for the simultaneous occurrence of several different relative cues of distances to increase the veridicality of the perception of absolute distance. To test whether this actually occurs, a three-dimensional display was viewed monocularly while moving the head laterally, under conditions in which some error in perceived absolute distance was expected. The perceived absolute distance of the display was measured with the number of relative cues of distance within the display varied. No systematic reduction was found in the error in perceived absolute distance as a consequence of the variation in the number of relative cues. The study provides no evidence that the potential source of absolute distance information provided by relative cues is utilized by the visual system.     

From majority to minority and vice versa: the asymmetrical effects of losing and gaining majority position within a group

Two studies examined the effects of stable, partially changed, and completely changed majority and minority positions within a group on perception and evaluation of the group. It was hypothesized that loss of majority position (majority-to-minority change) would have stronger effects than gain of majority position (minority-to-majority change). The hypothesized asymmetrical effect was demonstrated in that loss of majority position decreased perception of group-self similarity, group attraction, and expectations for positive interactions with the group, whereas a corresponding gain of position did not increase them. Thus immediately following changes, the group is especially fragile because disintegrative forces created by the loss of majority position are stronger than integrative forces created by the gain of majority position.     

Perceptual projects:A theory of veridicality and distortion in perception

Abstract.— The split between objective and subjective information, characterizing dualistic theories of perception, is argued to have caused contradictions around the problems of veridicality of perception and the attention-attracting power of stimulus properties. The theory of threshold-regulation in categorical perception is criticized and an alternative model is suggested, where the main distinctions are between the "knowing how" and the "knowing that" of perception, between exteriorization and interiorization, and between the perceptual project and the perceptual foundation. It is demonstrated that concepts used in the analysis of dialogical communication are useful in the theory of perception to explain phenomena such as curiosity, boredom, and pathological perception.     

What remains on your mind after you are done?: Flexible regulation of knowledge accessibility

The accessibility of stored knowledge has been found to decline over time after activation without further stimulation. A special case is goal pursuit; goal-related knowledge remains accessible until goal completion, and then its accessibility declines rapidly. We hypothesized that after goal completion the decline in accessibility of goal-related knowledge would be especially rapid for strong promotion-focused individuals because their motivation to eagerly advance beyond the status quo would make accessibility of this knowledge an irrelevant detriment. We hypothesized an opposite effect for strongly prevention-predominant individuals because their motivation to vigilantly maintain a satisfactory state would make accessibility of this knowledge continually relevant. The results of two studies supported both these predicted moderators of accessibility change. Indeed, we found that for strongly prevention-predominant participants, knowledge accessibility actually increased over time after goal completion. We discuss how even basic cognitive mechanisms, like changes in accessibility, can be affected by general motivational concerns.     

Linear perspective and perceived size

A recent investigation (McDermott, 1965) revealed individual cues to distance had little effect on the perception of size. The present investigation paired each distance cue with linear perspective to determine the effect on size of combined distance cues. Separate groups of Ss were run in each of six combined cue conditions at three distances. For the most part, size matches were made in terms of retinal image size. It was hypothesized that relative or familiar size may be more relevant to size perception than distance cues.     

On counteradaptation

Often adaptation to artificially altered stimulation takes place because veridical stimulation that produces the same perceptual property that is produced by the altered stimulation is also received. In these cases, an assimilation of the two perceptual processes produced by the two different stimulations (the altered and the veridical) is supposed to be responsible for the adaptation that is achieved. This hypothesis, which was formulated by Wallach and Karsh (1963), would be confirmed by demonstrating a modification of the perceptual process produced by veridical stimulation rather than the one produced by the altered stimulation. We demonstrated this by having S observe in the dark for 20 min a luminous figure that objectively expanded as it moved toward S and contracted as it moved away. But instead of testing for changes in size perception as such, we tested for a change in the relation between accommodation and convergence on the one hand and registered distance on the other. In one experiment, such a change was measured by obtaining estimates of perceived size and depth before and after the adaptation period. Highly significant changes of size and significantly greater changes of stereoscopic depth were obtained. Inasmuch as stereoscopic vision was totally absent from the adaptation conditions, the change in stereoscopic depth that was larger than the size change can only be ascribed to a change in registered distance. In another experiment, we tested for a change in distance by having S point from the side to a vertical line, before and again after the adaptation period, under conditions where only accommodation and convergence could serve as distance cues. Significant changes in the pointing distance were measured, indicating more directly a change in the relation between these oculomotor adjustments and perceived distance. We propose the term counteradaptation for such modification of a perceptual process away from veridicality.     

Metamers in the haptic perception of heaviness and moveableness

It is hypothesized that heaviness perception for a freely wielded nonvisible object can be mapped to a point in a three-dimensional heaviness space. The three dimensions are mass, the volume of the inertia ellipsoid, and the symmetry of the inertia ellipsoid. Within this space, particular combinations yield heaviness metamers (objects of different mass that feel equally heavy), whereas other combinations yield analogues to the size-weight illusion (objects of the same mass that feel unequally heavy). Evidence for the two types of combinations was provided by experiments in which participants wielded occluded hand-held objects and estimated the heaviness of the objects relative to a standard. Further experiments with similar procedures showed that metamers of heaviness were metamers of moveableness but not metamers of length. A promising conjecture is that the haptic perceptual system maps the combination of an object's inertia for translation and inertia for rotation to a perception of the object's maneuverability.     

Negative bodily self in suicide attempters

In the present study we investigated the relationship between suicidal behavior and aspects of bodily perception and parental care. Measures of bodily perception included measures of tactile sensitivity, body attitudes, and body experiences. Measures of parental care included parental bonding, negative and positive touch, and early maltreatment. One hundred and two adolescents (suicidal and nonsuicidal inpatients, and a control group) participated in the study. It was hypothesized that suicidal adolescents would (1) have higher tactile sensation thresholds, and more negative body attitudes and experiences; and (2) report less parental care, lower positive and higher negative parental touch, and higher parental maltreatment. It was also hypothesized that bodily sensitivity would mediate the relationship between suicidal tendencies and perceived negative early care. These hypotheses were confirmed. The role of a negative bodily self in suicidal behavior is proposed and discussed.     

语言标签和自我关联对新颖客体类别知觉的影响

类别知觉(Categorical perception)是人类最基本的认知活动之一, 探讨语言对类别知觉的影响是心理语言学领域的热门话题之一。在这个研究的3个实验中, 分别在高、低不同的语言标签表征强度下、高、低不同的客体自我关联程度下观察新颖客体类别知觉的过程。研究发现, 语言标签表征程度的增强可促进新颖客体类别知觉的右视野优势效应; 客体与自我关联程度的提高会促进左、右视野的类别知觉效应; 语言标签的表征程度和客体与自我关联程度同时增强时, 语言标签的作用依旧表现出来, 但与自我关联的影响产生权衡分配, 且其影响力并不足以产生右视野优势效应。     

Neural correlates of object indeterminacy in art compositions

Indeterminate art invokes a perceptual dilemma in which apparently detailed and vivid images resist identification. We used event-related fMRI to study visual perception of representational, indeterminate and abstract paintings. We hypothesized increased activation along a gradient of posterior-to-anterior ventral visual areas with increased object resolution, and postulated that object resolution would be associated with visual imagery. Behaviorally, subjects were faster to recognize familiar objects in representational than in both indeterminate and abstract paintings. We found activation within a distributed cortical network that includes visual, parietal, limbic and prefrontal regions. Representational paintings, which depict scenes cluttered with familiar objects, evoked stronger activation than indeterminate and abstract paintings in higher-tier visual areas. Perception of scrambled paintings was associated with imagery-related activation in the precuneus and prefrontal cortex. Finally, representational paintings evoked stronger activation than indeterminate paintings in the temporoparietal junction. Our results suggest that perception of familiar content in art works is mediated by object recognition, memory recall and mental imagery, cognitive processes that evoke activation within a distributed cortical network.     

Object recognition and object segregation in 4.5-month-old infants

Six experiments investigated how 4.5-month-old infants' perception of a display is affected by an immediate prior experience with an object similar to part of the test display. Prior research (A. Needham & R. Baillargeon, 1998) showed that when infants see an object alone and then see it next to a novel object, this prior experience allows them to determine the location of a boundary between the two objects. The present experiments investigated whether infants would also use an object similar, but not identical, to a test object in the same kind of task. The results indicate that infants' use of a prior experience is disrupted by changes in the features of the object, but not by a change in its spatial orientation. These findings suggest that, like adults, infants may expect that changes in the features of an object are associated with a change in the identity of the object, but do not have the same expectation for changes in spatial orientation.     

Salient material properties and haptic volume perception: The influences of surface texture, thermal conductivity, and compliance

We investigated the influences of surface texture, thermal conductivity, and compliance on the haptic perception of the volume of small cubes. It was hypothesized that an object containing highly salient material properties would be perceived as larger in volume than the same object without these properties. Blindfolded subjects were asked to explore pairs of cubes differing in their material properties and to select the one with the larger volume. The results showed that, counterintuitively, a smooth cube was perceived as being significantly larger than a rough cube of the same physical volume, with average biases of about 19 %. Furthermore, cubes with a higher thermal conductivity were perceived as significantly larger than cubes with a lower thermal conductivity (average bias of about 7 %). In addition, the magnitude of the bias in this condition was not changed by increasing or decreasing the temperature of the test objects, suggesting that the effect of thermal conductivity could not be attributed directly to the heat flow. Finally, a hard cube was perceived as significantly larger than a soft cube of equal physical volume, with an average bias of about 25 %. These results reveal that the studied material properties have significant and consistent influences on the haptic perception of volume. The observed biases provide an indication of the levels at which the processing of haptic information on volume and material properties occurs.     

An Ecological Approach to Modeling Vision: Quantifying Form Perception Using the Circle Map Equation

Abstract

Object perception occurs within a dynamic world, where the environment and the observer (both body and eyes) are continually moving, shifting and changing. We seek to characterize and quantify this process from a perspective accounting for the interconnected system of motion in the environment, the perceiver and the eye, unfolding through time. Specifically, we build a mathematical representation for object perception based off the circle map equation. We describe an interaction between the eyes’ movement and the movement in the world, in order to better understand how those work together to result in perception. Across three experiments, we show that the stability of the relationship between object perception and complex eye movements can be perturbed and will have a predictable response to said perturbations. In so doing, we provide a different context – a dynamical systems framework – under which we can begin to consider the ecological validity of visual perception models, while recognizing the degree to which the visuo-spatial world is continuously being perturbed and disrupted. In fact, we postulate that such perturbations are capitalized on by the perceptual system, contributing to accurate object and motion identification.     

Shortening of subjective tone intervals followed by repetitive tone stimuli

Accumulated evidence shows that a subjective time interval is lengthened by preceding or concurrent presentation of flickers or repetitive tone stimuli that have been hypothesized to increase the frequency of pulse generation by a brain pacemaker. In the present study, we presented a series of repetitive tone stimuli after an interval that started and ended with tone markers. We found that subjective perception of the preceding interval was not lengthened but shortened by the tone stimuli that followed the interval. The perceived duration decreased as the frequency of the repetitive tone stimuli increased. The effect disappeared when the repetitive tone stimuli were delivered with a delay of 500 msec after the test interval or when continuous sound was delivered instead of delivering a rapid series of tones. On the basis of the results, we propose that the pulse count accumulated during a test interval was normalized by the clock frequency just after the test interval in a postdictive manner.     

A theory of veridical space perception

Abstract.— A theory of veridical space perception based on the principles of movement parallax is proposed. Since optical changes are ambiguous with regard to veridical distances it is suggested that veridicality is obtained on the basis of an interaction between optical information and information from the body-state system. The optical system generates size and shape constancy on the basis of proximal common motions described by a vector-derivative model. The body-state system is thought to register information in a similar manner, and the interaction between the two subsystems is assumed to function according to the vector-derivative principle.     

The effect of red color on perceived self‐attractiveness

Recent research showed that individuals are perceived as more attractive when presented with the color red. We seek to extend these findings by studying the effects of red color on individuals' perception of self‐attractiveness, rather than the attractiveness of others. Based on the color‐in‐context theory, we hypothesized that individuals would perceive themselves as more attractive under red chromatic conditions. In three experiments, participants were asked to wear a red or a blue shirt and rated their own attractiveness. As expected, participants in the red shirt condition indicated a higher level of self‐attractiveness than participants in the blue condition. Moreover, the results showed that the self‐perception red effect was mediated by the individuals' self‐perceived sexual receptivity and self‐perceived status.     

The role of a change heuristic in judgments of sound duration

The present study investigated whether the quality of a frequency change within a sound (i.e., smooth vs. abrupt) would influence perception of its duration. In three experiments, participants were presented with two consecutive sounds on each of a series of trials, and their task was to judge whether the second sound was longer or shorter in duration than the first. In Experiment 1, participants were more likely to judge sounds consisting of a smooth and continuous change in frequency as longer in duration than sounds that maintained a constant frequency. In Experiment 2, the same bias was observed for sounds incorporating an abrupt change in frequency, but only when the frequency change was relatively small. The results of Experiment 3 suggested that the application of a change heuristic when generating duration judgments depends on the perception of change as originating from a single, integrated perceptual object.