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Psychonomic Bulletin & Review Aug 2019The current study comprises the first systematic meta-analysis of weight illusions. We obtained descriptive data from studies in which subjective heaviness estimates... (Meta-Analysis)
Meta-Analysis Review
The current study comprises the first systematic meta-analysis of weight illusions. We obtained descriptive data from studies in which subjective heaviness estimates were made for pairs or groups of objects that had the same mass and different volumes (size-weight illusion; SWI) or different apparent material properties (material-weight illusion; MWI). Using these data, we calculated mean effect sizes to represent illusion strength. Other study details, including stimulus mass, volume, density, and degree of visual and somatosensory access to the stimuli were also recorded to quantify the contribution of these variables to effect sizes for the SWI. The results indicate that the SWI has a larger mean effect size than the MWI and that the former is consistent in strength when information about stimulus size is gained through somatosensory channels, regardless of visual access. The SWI is weaker when only the visual system provides size information. Effect sizes for the SWI were larger when there was a greater difference in volume across the stimuli. There was also a positive correlation between SWI strength and the difference in physical density across the different experimental stimuli, even after controlling for volume differences. Together, we argue that these findings provide support for theories of weight illusions that are based on conceptual expectancies as well as those that are based on bottom-up processing of physical density. We further propose that these processes, which have been considered dichotomously in the past, may not be mutually exclusive from each other and could both contribute to our perception of weight when we handle objects in everyday life.
Topics: Humans; Illusions; Size Perception; Weight Perception
PubMed: 31044361
DOI: 10.3758/s13423-019-01604-x -
Attention, Perception & Psychophysics Apr 2021Perception, representation, and memory of ensemble statistics has attracted growing interest. Studies found that, at different abstraction levels, the brain represents...
Perception, representation, and memory of ensemble statistics has attracted growing interest. Studies found that, at different abstraction levels, the brain represents similar items as unified percepts. We found that global ensemble perception is automatic and unconscious, affecting later perceptual judgments regarding individual member items. Implicit effects of set mean and range for low-level feature ensembles (size, orientation, brightness) were replicated for high-level category objects. This similarity suggests that analogous mechanisms underlie these extreme levels of abstraction. Here, we bridge the span between visual features and semantic object categories using the identical implicit perception experimental paradigm for intermediate novel visual-shape categories, constructing ensemble exemplars by introducing systematic variations of a central category base or ancestor. In five experiments, with different item variability, we test automatic representation of ensemble category characteristics and its effect on a subsequent memory task. Results show that observer representation of ensembles includes the group's central shape, category ancestor (progenitor), or group mean. Observers also easily reject memory of shapes belonging to different categories, i.e. originating from different ancestors. We conclude that complex categories, like simple visual form ensembles, are represented in terms of statistics including a central object, as well as category boundaries. We refer to the model proposed by Benna and Fusi (bioRxiv 624239, 2019) that memory representation is compressed when related elements are represented by identifying their ancestor and each one's difference from it. We suggest that ensemble mean perception, like category prototype extraction, might reflect employment at different representation levels of an essential, general representation mechanism.
Topics: Brain; Brain Mapping; Concept Formation; Humans; Judgment; Semantics; Visual Perception
PubMed: 33420715
DOI: 10.3758/s13414-020-02174-0 -
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 -
Proceedings. Biological Sciences Jul 2020Perceiving the positions of objects is a prerequisite for most other visual and visuomotor functions, but human perception of object position varies from one individual...
Perceiving the positions of objects is a prerequisite for most other visual and visuomotor functions, but human perception of object position varies from one individual to the next. The source of these individual differences in perceived position and their perceptual consequences are unknown. Here, we tested whether idiosyncratic biases in the underlying representation of visual space propagate across different levels of visual processing. In Experiment 1, using a position matching task, we found stable, observer-specific compressions and expansions within local regions throughout the visual field. We then measured Vernier acuity (Experiment 2) and perceived size of objects (Experiment 3) across the visual field and found that individualized spatial distortions were closely associated with variations in both visual acuity and apparent object size. Our results reveal idiosyncratic biases in perceived position and size, originating from a heterogeneous spatial resolution that carries across the visual hierarchy.
Topics: Humans; Size Perception; Space Perception; Visual Acuity; Visual Fields; Visual Perception
PubMed: 32635869
DOI: 10.1098/rspb.2020.0825 -
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 -
Women & Health Apr 2023Body size perception among young women in Asian and Western countries is believed to be quite different, however, there are no confirming studies. We analyzed the data...
Body size perception among young women in Asian and Western countries is believed to be quite different, however, there are no confirming studies. We analyzed the data from young women aged between 20 and 40 who participated in the National Health and Nutrition Examination Survey (2001-2018) of the United States (US) and Korea. US young women had higher rates of being overweight and obesity than Korean young women, and there was no significant change over 20 years. In both countries, the percentage of properly estimating one's own weight exceeded 70 percent and remained relatively steady. The percentage of overestimating one's own weight was only about 10 percent in Korea in 2001, but increased to 20 percent. In the case of the US, the percentage was about 15 percent in 2001-2002, but has since continued to decline. The percentage of underestimating one's own body weight was about 18 percent in Korea in 2001, but decreased to about 8 percent. In the case of the US, the percentage was very low at about 10 percent in 2001-2002, but gradually increased to about 18 percent in 2017-2018. In conclusion, young women in the US tend to underestimate their body size, and those in Korea tend to overestimate it.
Topics: Humans; Female; United States; Young Adult; Adult; Nutrition Surveys; Size Perception; Obesity; Overweight; Republic of Korea; Body Mass Index
PubMed: 36849421
DOI: 10.1080/03630242.2023.2183345 -
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