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Scientific Reports Sep 2022We investigated whether brief non-judgmental focus on the details of one's non-dominant hand might lead to changes in perception of its size, and if such a change would...
We investigated whether brief non-judgmental focus on the details of one's non-dominant hand might lead to changes in perception of its size, and if such a change would be related to central coherence, body dissatisfaction, or how much participants liked their hand. After two pilot experiments (N = 28 and N = 30 respectively: Appendix 1), a within-subject experiment (N = 82) was conducted. Subjects were mainly university students. They were asked to rate the size of their non-dominant hand and how much they liked it, and the size of an external object (a X-box controller) on a visual-analog scale before and after focusing on their details for 5 min, as well as the size of another object (a calculator) before and after a 5 min long distraction task. After completing the tasks, they were asked to respond to a brief questionnaire on body dissatisfaction. A s significant interaction between time and factors (non-dominant hand, X-box controller and calculator) emerged (F(2, 78) = 6.41, p = .003). Participants rated their hand as larger after focusing on its details compared to baseline, and this change was significantly larger than those reported for the X-box controller. No significant change in how they liked their hand was observed, and contrary to the pilot experiments, the perceived change in size of the hand was not related to body dissatisfaction. The significant change in reporting of the size of the hand after focusing on its details seems to be an interesting finding, worth further replications.
Topics: Hand; Humans; Judgment; Size Perception
PubMed: 36123432
DOI: 10.1038/s41598-022-19919-6 -
Consciousness and Cognition Jan 2020Previous work revealed that humans can keep track of the direction and degree of errors in their temporal and numerical reproductions/estimations. Given the behavioral...
Previous work revealed that humans can keep track of the direction and degree of errors in their temporal and numerical reproductions/estimations. Given the behavioral and psychophysical commonalities to various magnitudes and the implication of an overlapping neuroanatomical locus for their representation, we hypothesized that participants would capture the direction of errors and confidence ratings would track the magnitude of errors in line-length reproductions. In two experiments, participants reproduced various target lengths as accurately as possible, and reported the direction of their errors and provided confidence ratings for their reproductions. The isolated analysis of these two second-order judgments showed that participants can correctly report the direction of errors in their line-length reproductions and subjective confidence decreases as the magnitude of errors increases. These results show that humans can robustly keep track of the direction of errors in their line-length reproductions and their subjective confidence corroborates the magnitude of these errors.
Topics: Adult; Executive Function; Humans; Mathematical Concepts; Metacognition; Size Perception; Space Perception; Visual Perception; Young Adult
PubMed: 31698181
DOI: 10.1016/j.concog.2019.102831 -
The Journal of Sexual Medicine Mar 2020Poor genital self-image is a common phenomenon leading to an increasing interest in female genital surgery over the last years.
INTRODUCTION
Poor genital self-image is a common phenomenon leading to an increasing interest in female genital surgery over the last years.
AIM
The aim was to correlate objective measurements of the labia minora with the individual subjective perception of the labial size.
METHODS
In a cross-sectional study with 200 premenopausal women (median age 33.5 years) presenting for gynecological issues other than vulvar diseases, labial width and length were measured, and psychological and physical complaints were assessed. Multivariable logistic regression analyses were performed to identify factors that influenced self-reported complaints and subjective perception of labia size.
MAIN OUTCOME MEASURE
The main outcome measure was labial appearance (width and length in mm, color), subjective perception of the labial size, and complaints.
RESULTS
The median width of the labia minora was 19.0 mm (interquartile range = 12.6-27.5), and the median length was 35.5 mm (interquartile range = 27.8-48.9). The objective size of the labia was significantly associated with womens' subjective perception of the labial size, but not with self-reported complaints. Nearly one-third of the women (n = 53, 27%) reported complaints of their labia minora which were mainly physical (n = 41, 77%) or a combination of physical and psychological problems (n = 9, 17%), while only a small group reported experiencing only psychological complaints (n = 3, 6%). Predictors of complaints were previous cosmetic surgery and the subjective perception of the labia size. The latter was significantly associated with discomfort during intercourse and when visiting a sauna and by labia minora that protruded over the labia majora.
CLINICAL IMPLICATIONS
Cutoff values to define labial hypertrophy and to justify labial reduction surgery should be avoided.
STRENGTH & LIMITATIONS
This is a large sample of labial measurements in women not seeking labiaplasty. Standardized and validated questions regarding quality of life, sexuality, and body image could have provided more insight into psychological aspects.
CONCLUSION
These data demonstrate the variability of labial anatomy and its perception. Widschwendter A, Riedl D, Freidhager K, et al. Perception of Labial Size and Objective Measurements-Is There a Correlation? A Cross-Sectional Study in a Cohort Not Seeking Labiaplasty. J Sex Med 2020;17:461-469.
Topics: Adolescent; Adult; Body Image; Cohort Studies; Cross-Sectional Studies; Female; Gynecologic Surgical Procedures; Humans; Hypertrophy; Middle Aged; Quality of Life; Plastic Surgery Procedures; Vulva; Young Adult
PubMed: 31918983
DOI: 10.1016/j.jsxm.2019.11.272 -
Public Health Nutrition Mar 2022To synthesise evidence on body size preferences for females living in Africa and the factors influencing these. (Review)
Review
OBJECTIVE
To synthesise evidence on body size preferences for females living in Africa and the factors influencing these.
DESIGN
Mixed-methods systematic review including searches on Medline, CINHAL, ASSIA, Web of Science and PsycINFO (PROSPERO CRD42015020509). A sequential-explanatory approach was used to integrate quantitative and qualitative findings.
SETTING
Urban and rural Africa.
PARTICIPANTS
Studies of both sexes providing data on body size preferences for adolescent girls and women aged ≥10 years.
RESULTS
Seventy-three articles from twenty-one countries were included: fifty quantitative, fifteen qualitative and eight mixed methods. Most studies reported a preference for normal or overweight body sizes. Some studies of adolescent girls/young women indicated a preference for underweight. Factors influencing preferences for large(r) body sizes included: socio-demographic (e.g. education, rural residency), health-related (e.g. current BMI, pubertal status), psycho-social (e.g. avoiding HIV stigma) and socio-cultural factors (e.g. spouse's preference, social standing, cultural norms). Factors influencing preferences for slim(mer) body sizes included: socio-demographic (e.g. higher socioeconomic status, urban residency, younger age), health-related (e.g. health knowledge, being nulliparous), psycho-social (e.g. appearance, body size perception as overweight/obese) and socio-cultural factors (e.g. peer pressure, media).
CONCLUSIONS
Preference for overweight (not obese) body sizes among some African females means that interventions need to account for the array of factors that maintain these preferences. The widespread preference for normal weight is positive in public health terms, but the valorisation of underweight in adolescent girls/young women may lead to an increase in body dissatisfaction. Emphasis needs to be placed on education to prevent all forms of malnutrition.
Topics: Adolescent; Africa; Body Mass Index; Body Size; Female; Humans; Male; Obesity; Overweight; Thinness
PubMed: 33593472
DOI: 10.1017/S1368980021000768 -
Nutrients Jun 2021The influence of dishware on portion size perception in children and adolescents is inconclusive. This study investigated how children and adolescents with both obesity...
PURPOSE
The influence of dishware on portion size perception in children and adolescents is inconclusive. This study investigated how children and adolescents with both obesity and a normal weight perceived portion size in different sized and shaped dishware items.
METHODS
The study included 60 children and adolescents with overweight and obesity (OBE) and 27 children and adolescents with normal weight (NW) aged from 9 to 17 years. The participants estimated quantities in three pairs of drinking glasses, one pair of bowls and two pairs of plates which varied in size and shape. The children were instructed to state intuitively which portion they would choose for big or small thirst/hunger. Thereafter they were asked to determine the exact amount by answering which dishware item contained the larger/smaller portion (cognitive evaluation).
RESULTS
There were no substantial differences in the intuitive evaluation of portion sizes between OBE and NW. During the cognitive evaluation, OBE estimated the amount of water in the glasses more correctly compared to NW (61% vs. 43%; = 0.008); OBE estimated the amount of lentils in the bowls and on the plates significantly less correctly (39%) compared to NW (56%; = 0.013).
CONCLUSIONS
Habit formation and environmental stimuli might play a greater role in estimating food amounts in dishware than the child's and adolescent's body weight.
Topics: Adolescent; Case-Control Studies; Child; Cooking and Eating Utensils; Drinking Behavior; Feeding Behavior; Female; Humans; Male; Pediatric Obesity; Portion Size
PubMed: 34208625
DOI: 10.3390/nu13062062 -
Journal of Experimental Child Psychology Jan 2021Previous research has demonstrated a functional dissociation between vision for perception and vision for action. However, the developmental trajectory of this...
Previous research has demonstrated a functional dissociation between vision for perception and vision for action. However, the developmental trajectory of this functional dissociation is not well understood. We directly compared the sensitivity of grasping and perceptual estimations within the same experimental design to the real and illusory sizes of objects positioned in the Ponzo illusion display. Two different-sized objects were placed such that the differences between their real sizes and their perceived sizes were pitted against each other. Children aged 5-8 years and adults made perceptual size discriminations and then grasped (action) or estimated (perception) one of the objects based on its perceived size. Consistent with previous results, for the action task, grasping apertures of adults were scaled with the physical differences in the objects' sizes, even in trials where their overt perceptual decisions were deceived by the illusion. In contrast, perceptual estimations were robustly modulated by the illusion. Interestingly, children outperformed adults in their perceptual discriminations but exhibited adult-like behavior in grasping and in perceptual estimations of the objects, demonstrating a dissociation between perception and action. These results suggest that although the two visual functions are not operating at fully mature levels during childhood, some key mechanisms that support a dissociation between these functions are already in place.
Topics: Adolescent; Adult; Child; Child, Preschool; Female; Hand; Hand Strength; Humans; Illusions; Male; Psychomotor Performance; Size Perception; Visual Perception; Young Adult
PubMed: 33011386
DOI: 10.1016/j.jecp.2020.104986 -
Cognition Aug 2023Weber's law, the principle that the uncertainty of perceptual estimates increases proportionally with object size, is regularly violated when considering the uncertainty...
Weber's law, the principle that the uncertainty of perceptual estimates increases proportionally with object size, is regularly violated when considering the uncertainty of the grip aperture during grasping movements. The origins of this perception-action dissociation are debated and are attributed to various reasons, including different coding of visual size information for perception and action, biomechanical factors, the use of positional information to guide grasping, or, sensorimotor calibration. Here, we contrasted these accounts and compared perceptual and grasping uncertainties by asking people to indicate the visually perceived center of differently sized objects (Perception condition) or to grasp and lift the same objects with the requirement to achieve a balanced lift (Action condition). We found that the variability (uncertainty) of contact positions increased as a function of object size in both perception and action. The adherence of the Action condition to Weber's law and the consequent absence of a perception-action dissociation contradict the predictions based on different coding of visual size information and sensorimotor calibration. These findings provide clear evidence that human perceptual and visuomotor systems rely on the same visual information and suggest that the previously reported violations of Weber's law in grasping movements should be attributed to other factors.
Topics: Humans; Psychomotor Performance; Differential Threshold; Visual Perception; Movement; Hand Strength
PubMed: 37150154
DOI: 10.1016/j.cognition.2023.105465 -
Physiology & Behavior Apr 2024Oral perception of food particles is important in mastication and swallowing. However, the mechanism underlying particle perception remains poorly understood because of...
Oral perception of food particles is important in mastication and swallowing. However, the mechanism underlying particle perception remains poorly understood because of the lack of suitable experimental systems. We evaluated microparticle perception in rats utilizing insoluble cellulose particles of varying diameters (20-170 μm). The cellulose additives have polycrystalline morphologies and contain smaller crushed particles. The filtrate containing 20 μm particles at a concentration of 1.6% was passed through 3 μm pore-size filter paper, and numerous small particles equivalent to a 0.25 mM soluble solution were observed. In two-bottle preference tests, rats showed no innate preference or avoidance of particles of any size at concentrations ranging from 0.05-1.6%. Next, conditioned preference learning tests employing 8% glucose and fructose solutions were performed. After being repeatedly presented with glucose and fructose solutions containing particles of different sizes (170 and 20 μm particles or 20 μm filtrate) at a concentration of 1.6%, the rats preferred particles in glucose solution even without glucose presentation. Intriguingly, rats preferred the filtrate following repeated presentations of glucose-containing filtrate and water containing fructose. These results suggest that rats can distinguish microparticles in water. The preference learning test is useful for analyzing particle perception mechanisms in mammals.
Topics: Rats; Animals; Cellulose; Conditioning, Classical; Fructose; Glucose; Water; Food Preferences; Mammals
PubMed: 38336088
DOI: 10.1016/j.physbeh.2024.114486 -
Acta Psychologica Apr 2021The representation of space, time and number is believed to rely on a common encoding system developed to support action guidance. While the ecological advantage of such... (Review)
Review
The representation of space, time and number is believed to rely on a common encoding system developed to support action guidance. While the ecological advantage of such a shared system is evident when objects are located within the region of space we can act on (known as peri-personal space), it is less obvious in the case of objects located beyond our arms' reach. In the current study we investigated whether and to what extent the distance of the stimuli from the observer affects the perception of duration and numerosity. We first replicated Anelli et al.'s (2015) experiment by asking adult participants to perform a duration reproduction task with stimuli of different sizes displayed in the peri- or extra-personal space, and then applied the same paradigm to a non-symbolic numerosity estimation task. Results show that, independently of size, duration estimates were overestimated when visual stimuli were presented in the extra-personal space, replicating previous findings. A similar effect was also found for numerosity perception, however overestimation for far stimuli was much smaller in magnitude and was accounted by the difference in perceived size between stimuli presented in peripersonal or extrapersonal space. Overall, these results suggest that, while the processing of temporal information is robustly affected by the position of the stimuli in either the peri- or extra-personal space, numerosity perception is independent from stimulus distance. We speculate that, while time and numerosity may be encoded by a shared system in the peri-personal space (to optimize action execution), different and partially independent mechanisms may underlie the representation of time and numerosity in extra-personal space. Furthermore, these results suggest that investigating magnitude perception across spatial planes (where it is or is not possible to act) may unveil processing differences that would otherwise pass unnoticed.
Topics: Adult; Arm; Humans; Personal Space; Space Perception
PubMed: 33765520
DOI: 10.1016/j.actpsy.2021.103296 -
Scientific Reports Nov 2022Knowledge of one's own body size is a crucial facet of body representation, both for acting on the environment and perhaps also for constraining body ownership. However,...
Knowledge of one's own body size is a crucial facet of body representation, both for acting on the environment and perhaps also for constraining body ownership. However, representations of body size may be somewhat plastic, particularly to allow for physical growth in childhood. Here we report a developmental investigation into the role of hand size in body representation (the sense of body ownership, perception of hand position, and perception of own-hand size). Using the rubber hand illusion paradigm, this study used different fake hand sizes (60%, 80%, 100%, 120% or 140% of typical size) in three age groups (6- to 7-year-olds, 12- to 13-year-olds, and adults; N = 229). We found no evidence that hand size constrains ownership or position: participants embodied hands which were both larger and smaller than their own, and indeed judged their own hands to have changed size following the illusion. Children and adolescents embodied the fake hands more than adults, with a greater tendency to feel their own hand had changed size. Adolescents were particularly sensitive to multisensory information. In sum, we found substantial plasticity in the representation of own-body size, with partial support for the hypothesis that children have looser representations than adults.
Topics: Adult; Child; Adolescent; Humans; Illusions; Body Image; Proprioception; Visual Perception; Hand; Touch Perception
PubMed: 36369342
DOI: 10.1038/s41598-022-23716-6