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Attention, Perception & Psychophysics Feb 2020Visual statistical summary processing enables people to extract the average feature of a set of items rapidly and accurately. Previous studies have demonstrated...
Visual statistical summary processing enables people to extract the average feature of a set of items rapidly and accurately. Previous studies have demonstrated independent mechanisms for summarizing low (e.g. color, orientation) and high-level (facial identity, emotion) visual information. However, no study to date has conclusively determined whether there are feature-specific summarization mechanisms for low-level features or whether there are low-level, feature agnostic summarization mechanisms. To address this issue, we asked participants to report either the average orientation or the average size from a set of lines where both features varied. Participants completed these tasks either in single-task or mixed-task conditions; in the latter, successful performance required extraction of both summaries concurrently. If there were feature-specific summarization mechanisms that could operate in parallel, then errors in mean size and mean orientation tasks should be independent, in both single and mixed task conditions. On the other hand, a central domain-general mechanism for low-level summarization would imply a correlation between errors for both features and greater error in the mixed than single task trials. In Experiment 1, we found that there was no correlation between the mean size and mean orientation errors and performance was similar across single and mixed-task conditions, suggesting that there may be independent summarization mechanisms for size and orientation features. To further test the feature-specificity account, in Experiment 2 and 3 (with mask), we manipulated the display duration to determine whether there were any differences in the summarization of earlier (orientation) vs. later (size) features. While these experiments replicated the pattern of results observed in Experiment 1, at shorter display durations, no differences emerged across features. We argue that our data is consistent with independent, multi-level feature-specific statistical summary mechanisms for low-level visual features.
Topics: Cognition; Humans; Orientation, Spatial; Photic Stimulation; Size Perception; Space Perception
PubMed: 31900857
DOI: 10.3758/s13414-019-01942-x -
BMC Public Health Sep 2022Body image variables such as body size perception (BSP) and body size dissatisfaction (BSD) can influence health-related behaviors. However, few studies have...
BACKGROUND
Body image variables such as body size perception (BSP) and body size dissatisfaction (BSD) can influence health-related behaviors. However, few studies have investigated these body image variables in adolescent girls participating in a physical activity intervention. Therefore, the study objectives were to examine the 1) associations between health-related behaviors (physical activity, screen-time, eating habits and sleep duration) and BSP and BSD among girls participating in FitSpirit, a physical activity intervention for girls; and 2) influence of weight control practices on the association between health-related behaviors and BSP and BSD.
METHODS
This cross-sectional study assessed a sample of 545 adolescent girls (mean age: 15.0±1.5 years) from 240 schools. Body mass index, health-related behaviors, perceived actual body size and desired body size variables were self-reported and collected via an online questionnaire at the end of the FitSpirit intervention. A negative BSP score [perceived actual body size - calculated BMI z-score] indicates an underestimation of body size. A positive BSD score [perceived actual body size - desired body size] indicates a desire to reduce body size. A multiple linear regression analysis examined the effects of age, zBMI and health behaviors on BSP and BSD. A second multiple linear regression analysis examined the independent associations between BSP and BSD by weight control practice. The linear relationships between BSP and BSD were evaluated with Pearson's correlations.
RESULTS
Underestimation and dissatisfaction of body size are more prevalent in participants living with overweight/obesity. Screen-time and sleep duration were independently associated with BSP score (Beta=0.02; P<0.05 and Beta=-0.07; P<0.05, respectively), whereas only screen-time was associated with the BSD score (Beta=0.07; P<0.001). Physical activity was independently associated with the BSP score only in participants trying to control (maintain) their weight (Beta=-0.18; P<0.05).
CONCLUSIONS
Body size overestimation and dissatisfaction are associated with health-related behaviors, specifically with more screen-time and less optimal sleeping habits. Physical activity level does not appear to be associated with body image in girls engaged in a physical activity intervention and who want to lose or gain weight. Health promotion interventions could include screen-time and sleep components as they may influence body image.
Topics: Adolescent; Body Image; Body Mass Index; Cross-Sectional Studies; Female; Health Behavior; Humans; Overweight
PubMed: 36115946
DOI: 10.1186/s12889-022-14131-7 -
Perception Sep 2022Observers can voluntarily avoid reversals of an ambiguous, reversible figure, extending the duration of an intended percept. This is usually attributed to high-level,...
Observers can voluntarily avoid reversals of an ambiguous, reversible figure, extending the duration of an intended percept. This is usually attributed to high-level, top-down attentional processes. However, voluntary control is limited. Reversals occur despite attempts to avoid them. In two experiments, observers demonstrated significant, but limited, voluntary control over Necker cube perception. Cube size and cube completeness, variables associated with stimulus-driven processes involving neural adaptation, influenced the frequency of reversals regardless of observers' intentions. Results are consistent with the hybrid hypothesis that both top-down and bottom-up processes contribute to Necker-cube perception and support the hypothesis that the contribution of bottom-up processes is responsible for the limitation on voluntary control.
Topics: Attention; Humans; Perception; Photic Stimulation
PubMed: 35833335
DOI: 10.1177/03010066221109990 -
I-Perception 2023We investigated participants' ability to differentiate between random and organized two-dimensional tactile tiles with embossed dots and examined how this ability varies...
We investigated participants' ability to differentiate between random and organized two-dimensional tactile tiles with embossed dots and examined how this ability varies with size and participant age. Four experiments were conducted to evaluate the effect of these variations on participants' capacity to utilize touch in identifying which of two stimuli exhibited greater randomness. Participants were instructed to explore embossed tiles using both hands. The tiles had varying levels of randomness from organized to random sets. In Experiments 1, 2, and 4, the sets were of equal size, while in Experiment 3, they differed in size. Results revealed a significant difference between the random and organized sets, with random stimuli being more easily discernible. These findings suggest that touch can be utilized to discern random patterns on tactile maps or displays. However, older participants encountered difficulties making this distinction, indicating similarities between vision and touch in perceiving randomness.
PubMed: 38033429
DOI: 10.1177/20416695231214954 -
Journal of Vision Sep 2021Although the familiar size of real-world objects affects size and distance perception, evidence is mixed about whether this is the case when oculomotor cues are...
Although the familiar size of real-world objects affects size and distance perception, evidence is mixed about whether this is the case when oculomotor cues are available. We examined the familiar size effect (FSE) on both size and distance perception for real objects under two viewing conditions with full or restricted oculomotor cues (binocular viewing, which provides vergence and accommodation cues, and monocular viewing through a 1-mm pinhole, which removes those cues). Familiar objects (a playing die versus a Rubik's cube) were manufactured in their typical (1.6-cm die and 5.7-cm Rubik's cube) and reverse (5.7-cm die and 1.6-cm Rubik's cube) sizes and shown at two distances (25 cm versus 91 cm) in isolation. Small near and large far objects subtended equal retinal angles. Participants provided manual estimates of perceived size and distance. For every combination of size and distance, Rubik's cubes were perceived as larger and farther than the dice, even during binocular viewing at near distances (<1 meter), when oculomotor cues are particularly strong. For size perception but not distance perception, the familiar size effect was significantly stronger under monocular pinhole viewing than binocular viewing. These results suggest that (1) familiar size affects the accuracy of perception, not just the speed; (2) the effect occurs even when oculomotor cues are available; and (3) size and distance perception are not perfectly yoked.
Topics: Accommodation, Ocular; Cues; Depth Perception; Distance Perception; Eye Movements; Humans; Size Perception; Vision, Binocular
PubMed: 34581767
DOI: 10.1167/jov.21.10.21 -
Childhood Obesity (Print) Oct 2021To examine the association between body size perception (BSP) and body size dissatisfaction (BSD) in elementary school children and to document the potential...
To examine the association between body size perception (BSP) and body size dissatisfaction (BSD) in elementary school children and to document the potential contribution of individual factors [age, sex, and actual body size (BMI -scores: BMI)] that may influence their relationship. This study included 269 children (124 boys and 145 girls) between 6 and 13 years of age (9.2 ± 1.6 years). The BSP score was calculated as the difference between the perceived actual body size and BMI (actual body size). A negative BSP score indicated an underestimation of their body size. To assess the BSD score, the difference between perceived actual body size and desired body size was calculated. A positive BSD score indicated a desire to be thinner. Perceived actual body size was smaller than BMI, independent of age group and weight status. Overall, 64% of children underestimated their body size. The young children living with obesity demonstrated the highest misperception. Results also showed that the proportion of children who desired to be thinner was higher in overweight and obese subgroups. No significant relationship was found between BSP and BSD scores in the entire sample, while a positive association was observed among younger children in the normal-weight and obese subgroups ( = 0.40; < 0.001 and = 0.78; < 0.05, respectively). Underestimation and dissatisfaction of body size are more prevalent in children living with overweight/obesity. Moreover, there is an association between BSP and dissatisfaction, yet this association is dependent on age and weight status.
Topics: Body Image; Body Mass Index; Body Size; Body Weight; Child; Child, Preschool; Female; Humans; Male; Overweight; Pediatric Obesity; Schools
PubMed: 34009006
DOI: 10.1089/chi.2020.0221 -
Plastic and Reconstructive Surgery Apr 2022Patients increasingly use photographs taken with a front-facing smartphone camera-"selfies"-to discuss their goals with a plastic surgeon. The purpose of this study was...
BACKGROUND
Patients increasingly use photographs taken with a front-facing smartphone camera-"selfies"-to discuss their goals with a plastic surgeon. The purpose of this study was to quantify changes in size and perception of facial features when taking a selfie compared to the gold standard of clinical photography.
METHODS
Thirty volunteers took three series of photographs. A 12-inch and 18-inch series were taken with a front-facing smartphone camera, and the 5-foot clinical photography series was taken with a digital single-lens reflex camera. Afterward, subjects filled out the FACE-Q inventory, once when viewing their 12-inch selfies and once when viewing their clinical photographs. Measurements were taken of the nose, lip, chin, and facial width.
RESULTS
Nasal length was, on average, 6.4 percent longer in 12-inch selfies compared to clinical photography, and 4.3 percent longer in 18-inch selfies compared to clinical photography. The alar base width did not change significantly in either set of selfies compared to clinical photography. The alar base to facial width ratio represents the size of the nose in relation to the face. This ratio decreased 10.8 percent when comparing 12-inch selfies to clinical photography (p < 0.0001) and decreased 7.8 percent when comparing 18-inch selfies to clinical photography (p < 0.0001).
CONCLUSIONS
This study quantifies the change in facial feature size/perception seen in previous camera-to-subject distance studies. With the increasing popularity of front-facing smartphone photographs, these data allow for a more precise conversation between the surgeon and the patient. In addition, the authors' findings provide data for manufacturers to improve the societal impact of smartphone cameras.
CLINICAL QUESTION/LEVEL OF EVIDENCE
Diagnostic, III.
Topics: Humans; Nose; Perception; Photography; Plastic Surgery Procedures; Rhinoplasty; Surgery, Plastic
PubMed: 35139046
DOI: 10.1097/PRS.0000000000008961 -
PloS One 2021Recent studies have suggested that people's intent and ability to act also can influence their perception of their bodies' peripersonal space. Vice versa one could...
Recent studies have suggested that people's intent and ability to act also can influence their perception of their bodies' peripersonal space. Vice versa one could assume that the inability to reach toward and grasp an object might have an impact on the subject's perception of reaching distance. Here we tested this prediction by investigating body size and action capability perception of neurological patients suffering from arm paresis after stroke, comparing 32 right-brain-damaged patients (13 with left-sided arm paresis without additional spatial neglect, 10 with left-sided arm paresis and additional spatial neglect, 9 patients had neither arm paresis nor neglect) and 27 healthy controls. Nineteen of the group of right hemisphere stroke patients could be re-examined about five months after initial injury. Arm length was estimated in three different methodological approaches: explicit visual, explicit tactile/proprioceptive, and implicit reaching. Results fulfilled the working hypothesis. Patients with an arm paresis indeed perceived their bodies differently. We found a transient overestimation of the length of the contralesional, paretic arm after stroke. Body size and action capability perception for the extremities thus indeed seem to be tightly linked in humans.
Topics: Aged; Arm; Body Size; Case-Control Studies; Female; Humans; Male; Middle Aged; Paresis; Proprioception; Size Perception; Stroke
PubMed: 34086777
DOI: 10.1371/journal.pone.0252596 -
Frontiers in Neurorobotics 2020In perceptual psychology, estimations of visual depth and size under different spatial layouts have been extensively studied. However, research evidence in virtual...
In perceptual psychology, estimations of visual depth and size under different spatial layouts have been extensively studied. However, research evidence in virtual environments (VE) is relatively lacking. The emergence of human-computer interaction (HCI) and virtual reality (VR) has raised the question of how human operators perform actions based on the estimation of visual properties in VR, especially when the sensory cues associated with the same object are conflicting. We report on an experiment in which participants compared the size of a visual sphere to a haptic sphere, belonging to the same object in a VE. The sizes from the visual and haptic modalities were either identical or conflicting (with visual size being larger than haptic size, or vice versa). We used three standard haptic references (small, medium, and large sizes) and asked participants to compare the visual sizes with the given reference, by method of constant stimuli. Results show a dominant functional priority of the visual size perception. Moreover, observers demonstrated a central tendency effect: over-estimation for smaller haptic sizes but under-estimation for larger haptic sizes. The results are in-line with previous studies in real environments (RE). We discuss the current findings in the framework of adaptation level theory for haptic size reference. This work provides important implications for the optimal design of human-computer interactions when integrating 3D visual-haptic information in a VE.
PubMed: 32372939
DOI: 10.3389/fnbot.2020.00018 -
Experimental Brain Research Apr 2020Size constancy is the ability to perceive objects as remaining constant in size regardless of their distance from the observer. Emmert's law demonstrates that viewing...
Size constancy is the ability to perceive objects as remaining constant in size regardless of their distance from the observer. Emmert's law demonstrates that viewing distance determines the perceived size of afterimages according to the amount of depth cues that are available. Using an afterimage paradigm, we examined to what extent removing stereopsis and other depth cues affects size-distance scaling. Thirty participants 'projected' afterimages onto a surface presented at different distances under binocular, monocular, and eyes-closed conditions. The perceived size of the afterimages closely followed the size-distance scaling predictions made by Emmert's law under binocular testing conditions, when all depth cues were available. In contrast, monocular testing decreased adherence to Emmert's law, while the eyes-closed condition resulted in a greater breakdown of size-distance scaling. Because we used an afterimage paradigm, this study provides the first demonstration of how perceived size is modulated by the availability of depth cues under conditions with a constant retinal image stimulus.
Topics: Adult; Afterimage; Depth Perception; Distance Perception; Female; Humans; Male; Psychological Theory; Size Perception; Vision, Binocular; Vision, Monocular; Young Adult
PubMed: 32215670
DOI: 10.1007/s00221-020-05747-5