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Perception Nov 2021Many who suffer from eating disorders claim that they see themselves as "fat". Despite decades of research into the phenomenon, behavioural evidence has failed to...
Many who suffer from eating disorders claim that they see themselves as "fat". Despite decades of research into the phenomenon, behavioural evidence has failed to confirm that eating disorders involve visual misperception of own-body size. I illustrate the importance of this phenomenon for our understanding of perceptual processing, outline the challenges involved in experimentally confirming it, and provide solutions to those challenges.
Topics: Feeding and Eating Disorders; Humans
PubMed: 34806479
DOI: 10.1177/03010066211056808 -
BMC Pediatrics Nov 2023Behavioural and emotional difficulties might play an important role in the development of body image disturbances, which represent serious risk factors for eating...
BACKGROUND
Behavioural and emotional difficulties might play an important role in the development of body image disturbances, which represent serious risk factors for eating disorders or depression. The present study provides a detailed overview on body image disturbances and several behavioural and emotional difficulties (differences between gender, age, and weight status) and their inter-relations in German children and adolescents.
METHODS
Data on body image disturbances, assessed through a Figure Rating Scale, and on behavioural and emotional difficulties, assessed through Goodman's Strengths and Difficulties Questionnaire (SDQ), were available for 5255 observations of 1982 German children and adolescents aged 8 to 18 years from the LIFE Child study, based in Leipzig, Germany. Associations were investigated using multiple logistic regression. Each association was checked for interaction with gender, age, and weight status.
RESULTS
Boys reported more behavioural difficulties than girls, while girls reported more emotional difficulties. Gender, age and weight status were related to behavioural and emotional difficulties as well as body image disturbances. Individuals with fewer difficulties were more satisfied with their own body. Children and adolescents who desired to be larger showed more prosocial behaviour problems, conduct and emotional problems and more signs of hyperactivity. Those, who desired to be thinner showed more problems in all SDQ-subscales. A more accurate body size perception was associated with fewer behavioural and emotional difficulties. Children and adolescents who overestimated their body size showed more prosocial behaviour and emotional problems. Underestimation one's body size was associated with more signs of hyperactivity.
CONCLUSION
The current findings highlight the importance of raising the awareness about the association between behavioural and emotional difficulties and body image disturbances in children and adolescents to prevent negative outcomes.
Topics: Male; Female; Humans; Child; Adolescent; Body Image; Surveys and Questionnaires; Emotions; Child Behavior Disorders; Risk Factors
PubMed: 37996808
DOI: 10.1186/s12887-023-04405-3 -
Attention, Perception & Psychophysics Apr 2021The natural environment is full of redundant information that the visual system compresses into an ensemble representation by averaging features of groups of items....
The natural environment is full of redundant information that the visual system compresses into an ensemble representation by averaging features of groups of items. Ensemble perception has been shown to operate with remarkable flexibility, efficiently integrating information across a variety of visual domains. In the current set of experiments, we tested whether average size representations reflect the physical size of objects displayed on a screen or perceptual transformations due to size constancy. We induced a perceptual change by presenting sets of triangles with linear perspective cues - lines converging at the horizon. Assuming a constant size, these cues cause individual objects "in the distance" to appear larger than objects without distance cues, due to size constancy heuristics. Observers viewed sets of triangles with and without linear perspective cues and judged whether a subsequently presented test triangle was larger or smaller than the average size of the preceding set. Results revealed ensemble size representations took size constancy into account, reflecting the perceived size of the triangles rather than their absolute size. Interestingly, the amount of bias exhibited was well characterized by the summed bias associated with each of the three triangles presented individually. Other pictorial cues to depth, such as occlusion and height-in-field, did not elicit the same bias when those were the only depth cues available. Overall, our results complement and extend other work showing that average size reflects the perceptual size of individual items in a set.
Topics: Cues; Depth Perception; Distance Perception; Humans; Judgment; Size Perception
PubMed: 33083990
DOI: 10.3758/s13414-020-02144-6 -
Neuropsychologia Aug 2022To efficiently process complex visual scenes, the visual system often summarizes statistical information across individual items and represents them as an ensemble....
To efficiently process complex visual scenes, the visual system often summarizes statistical information across individual items and represents them as an ensemble. However, due to the lack of techniques to disentangle the representation of the ensemble from that of the individual items constituting the ensemble, whether there exists a specialized neural mechanism for ensemble processing and how ensemble perception is computed in the brain remain unknown. To address these issues, we used a frequency-tagging EEG approach to track brain responses to periodically updated ensemble sizes. Neural responses tracking the ensemble size were detected in parieto-occipital electrodes, revealing a global and specialized neural mechanism of ensemble size perception. We then used the temporal response function to isolate neural responses to the individual sizes and their interactions. Notably, while the individual sizes and their local and global interactions were encoded in the EEG signals, only the global interaction contributed directly to the ensemble size perception. Finally, distributed attention to the global stimulus pattern enhanced the neural signature of the ensemble size, mainly by modulating the neural representation of the global interaction between all individual sizes. These findings advocate a specialized, global neural mechanism of ensemble size perception and suggest that global interaction between individual items contributes to ensemble perception.
Topics: Brain; Electroencephalography; Head; Humans; Photic Stimulation; Size Perception; Visual Perception
PubMed: 35697088
DOI: 10.1016/j.neuropsychologia.2022.108290 -
Attention, Perception & Psychophysics Apr 2021There is a growing body of research on ensemble perception, or our ability to form ensemble representations based on perceptual features for stimuli of varying levels of...
There is a growing body of research on ensemble perception, or our ability to form ensemble representations based on perceptual features for stimuli of varying levels of complexity, and more recently, on ensemble cognition, which refers to our ability to perceive higher-level properties of stimuli such as facial attractiveness or gaze direction. Less is known about our ability to form ensemble representations based on more abstract properties such as the semantic meaning associated with items in a scene. Previous work examining whether the meaning associated with digits can be incorporated into summary statistical representations suggests that numerical information from digit ensembles can be extracted rapidly, and likely using a parallel processing mechanism. Here, we further investigate whether participants can accurately generate summary representations of numerical value from digit sets and explore the effect of set size on their ability to do so, by comparing psychometric functions based on a numerical averaging task in which set size varied. Steeper slopes for ten- and seven-item compared to five-item digit sets provide evidence that displays with more digits yield more reliable discrimination between larger and smaller numerical averages. Additionally, consistent with previous reports, we observed a response bias such that participants were more likely to report that the numerical average was "greater than 5" for larger compared to smaller sets. Overall, our results contribute to evidence that ensemble representations for semantic attributes may be carried out via similar mechanisms as those reported for perceptual features.
Topics: Cognition; Face; Humans; Perception; Psychometrics; Semantics; Size Perception
PubMed: 33389674
DOI: 10.3758/s13414-020-02196-8 -
Appetite Dec 2020Exposure to food-related stimuli could lead to the triggering of a set of biological, emotional and cognitive responses. Such responses can be pronounced following food...
Exposure to food-related stimuli could lead to the triggering of a set of biological, emotional and cognitive responses. Such responses can be pronounced following food deprivation. Indeed, previous research showed that even a moderate period of food deprivation is sufficient to increase perceptual precision to detect changes along food size and to change the processing style of food-related stimuli. It is unclear, however, whether food deprivation also leads to systematic biases along the perception of food size. Here, we used two classic psychophysical methods, the method of constant stimuli and the method of adjustment, adapted to the field of food perception, to study the effect of food deprivation on average perceived food size. In two experiments, food deprived and non-deprived participants were asked to compare a series of food and non-food visual stimuli along their size. The results were inconsistent and depended upon the method used. When found, small bias effects resulted in food stimuli perceived as bigger following food deprivation. The results show that unlike the reliable effects motivational factors have on perceptual precision and on perceptual processing style, they have an inconsistent influence on average perceived food size.
Topics: Food; Food Deprivation; Humans; Motivation; Visual Perception
PubMed: 32822806
DOI: 10.1016/j.appet.2020.104829 -
Scientific Reports May 2022Our long-term goal is the development of a wearable warning system that uses electrocutaneous stimulation. To find appropriate stimulation parameters and electrode...
Our long-term goal is the development of a wearable warning system that uses electrocutaneous stimulation. To find appropriate stimulation parameters and electrode configurations, we investigate perception amplitude thresholds and qualitative perceptions of electrocutaneous stimulation for varying pulse widths, electrode sizes, and electrode positions. The upper right arm was stimulated in 81 healthy volunteers with biphasic rectangular current pulses varying between 20 and [Formula: see text]. We determined perception, attention, and intolerance thresholds and the corresponding qualitative perceptions for 8 electrode pairs distributed around the upper arm. For a pulse width of [Formula: see text], we find median values of 3.5, 6.9, and 13.8 mA for perception, attention, and intolerance thresholds, respectively. All thresholds decrease with increasing pulse width. Lateral electrode positions have higher intolerance thresholds than medial electrode positions, but perception and attention threshold are not significantly different across electrode positions. Electrode size between [Formula: see text] and [Formula: see text] has no significant influence on the thresholds. Knocking is the prevailing perception for perception and attention thresholds while mostly muscle twitching, pinching, and stinging are reported at the intolerance threshold. Biphasic stimulation pulse widths between [Formula: see text] and [Formula: see text] are suitable for electric warning wearables. Within the given practical limits at the upper arm, electrode size, inter-electrode distance, and electrode position are flexible parameters of electric warning wearables. Our investigations provide the basis for electric warning wearables.
Topics: Electric Stimulation; Electrodes; Humans; Perception; Sensation
PubMed: 35513410
DOI: 10.1038/s41598-022-10708-9 -
Journal of Vision Aug 2020Judging the poses, sizes, and shapes of objects accurately is necessary for organisms and machines to operate successfully in the world. Retinal images of...
Judging the poses, sizes, and shapes of objects accurately is necessary for organisms and machines to operate successfully in the world. Retinal images of three-dimensional objects are mapped by the rules of projective geometry and preserve the invariants of that geometry. Since Plato, it has been debated whether geometry is innate to the human brain, and Poincare and Einstein thought it worth examining whether formal geometry arises from experience with the world. We examine if humans have learned to exploit projective geometry to estimate sizes and aspects of three-dimensional shape that are related to relative lengths and aspect ratios. Numerous studies have examined size invariance as a function of physical distance, which changes scale on the retina. However, it is surprising that possible constancy or inconstancy of relative size seems not to have been investigated for object pose, which changes retinal image size differently along different axes. We show systematic underestimation of length for extents pointing toward or away from the observer, both for static objects and dynamically rotating objects. Observers do correct for projected shortening according to the optimal back-transform, obtained by inverting the projection function, but the correction is inadequate by a multiplicative factor. The clue is provided by the greater underestimation for longer objects, and the observation that they seem to be more slanted toward the observer. Adding a multiplicative factor for perceived slant in the back-transform model provides good fits to the corrections used by observers. We quantify the slant illusion with two different slant matching measurements, and use a dynamic demonstration to show that the slant illusion perceptually dominates length nonrigidity. In biological and mechanical objects, distortions of shape are manifold, and changes in aspect ratio and relative limb sizes are functionally important. Our model shows that observers try to retain invariance of these aspects of shape to three-dimensional rotation by correcting retinal image distortions due to perspective projection, but the corrections can fall short. We discuss how these results imply that humans have internalized particular aspects of projective geometry through evolution or learning, and if humans assume that images are preserving the continuity, collinearity, and convergence invariances of projective geometry, that would simply explain why illusions such as Ames' chair appear cohesive despite being a projection of disjointed elements, and thus supplement the generic viewpoint assumption.
Topics: Form Perception; Humans; Illusions; Imaging, Three-Dimensional; Mental Recall; Retina; Size Perception
PubMed: 32766745
DOI: 10.1167/jov.20.8.14 -
International Journal of Environmental... May 2022Body-size perception is an important factor in motivating people to lose weight. Study aim was to explore the perception of body image among first-generation Chinese...
Body-size perception is an important factor in motivating people to lose weight. Study aim was to explore the perception of body image among first-generation Chinese migrants living in Italy. A sample of 1258 Chinese first-generation immigrants and of 285 native Italians living in Prato, Italy, underwent blood pressure measurements, blood tests (with measurement of glucose, cholesterol, and triglycerides), and anthropometric measurements. Body-size perception was investigated with Pulvers’ figure rating scale using logistic or linear multivariable regression adjusted for age, gender, BMI, education and years spent in Italy. Chinese migrants had lower BMI and discrepancy score (preferred minus current body size) than Italians (p < 0.05 for both). After a logistic regression analysis, the discrepancy score remained lower in the Chinese than in the Italian cohort independently from BMI and other confounders (OR 0.68; 95%CI 0.50 to 0.92). In the Chinese cohort, female gender, BMI and years spent in Italy were positive determinants of discrepancy score (desire to be thinner), while age showed negative impact (p < 0.05 for all). Overweight is an important risk factor for diabetes, a very prevalent condition among first-generation Chinese migrants. The present study offers useful information and suggests the need for prevention programs specifically addressed to men.
Topics: Asian People; China; Cross-Sectional Studies; Female; Humans; Male; Overweight; Size Perception
PubMed: 35627600
DOI: 10.3390/ijerph19106063 -
Psychonomic Bulletin & Review Feb 2020Judgment of the location of a previously viewed moving or stationary target is often displaced in the direction of implied gravitational attraction, and this has been... (Review)
Review
Judgment of the location of a previously viewed moving or stationary target is often displaced in the direction of implied gravitational attraction, and this has been referred to as representational gravity. Variables that have been investigated for a possible influence on representational gravity include characteristics of the target (size/mass, velocity, distance traveled, orientation, modality), display (retention interval, response measure, height in the picture plane), context (nontarget intramodal stimuli, cross-modal components of a single stimulus), and observer (oculomotor behavior, body orientation, psychopathology), and several additional variables that might influence representational gravity but have not yet been investigated are suggested for future studies. Conclusions and speculations regarding the contribution and relationship of representational gravity to several variables, processes, and tasks (physical gravity, linear acceleration, subjective visual vertical, size/mass and weight, other biases in spatial localization, catching and intercepting a moving target, an internal model of gravity, naïve physics, a gravity heuristic, art and aesthetics) are discussed, and compatibility of representational gravity with Gibsonian and representational approaches is noted. It is suggested that representational gravity is an important adaptation that aids observers in interactions with physical objects in the environment, but that such an adaptation is not necessarily fully consistent with objective physical principles.
Topics: Adaptation, Physiological; Gravitation; Humans; Perception
PubMed: 31515734
DOI: 10.3758/s13423-019-01660-3