scholarly journals Dynamic Size-Weight Changes After Object Lifting Reduce the Size-Weight Illusion

2019 ◽  
Author(s):  
Vonne van Polanen ◽  
Marco Davare
Keyword(s):  
Virtual Reality ◽  
Time Window ◽  
Weight Perception ◽  
Critical Time ◽  
Perceptual Bias ◽  
Weight Changes ◽  
Standard Size ◽  
Heaviness Perception ◽  
Weight Illusion ◽  
Mismatch Theory

ABSTRACTIn the size-weight illusion, the smaller object from two equally weighted objects is typically perceived as being heavier. One explanation is that the mismatch between the weight expectation based on object size and actual sensory feedback influences heaviness perception. In most studies, the size of an object is perceived before its weight. We investigated whether size changes would influence weight perception if both would be perceived simultaneously. We used virtual reality to change the size and weight of an object after lifting and asked participants to judge whether objects became lighter or heavier. We found that simultaneous size-weight changes greatly reduced the size-weight illusion to perceptual biases below discrimination thresholds. In a control experiment in which we used a standard size-weight illusion protocol with sequential lifts of small and large objects in the same virtual reality setup, we found a larger, typical perceptual bias. These results show that the size-weight illusion is smaller when size and weight information is perceived simultaneously. This provides support for the prediction mismatch theory explaining the size-weight illusion. Furthermore, these findings suggest that the lifting phase is a critical time window during which brain mechanisms comparing perceived and expected weight mediate the size-weight illusion.

scholarly journals Dynamic size-weight changes after object lifting reduce the size-weight illusion

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Vonne van Polanen ◽  
Marco Davare
Keyword(s):  
Virtual Reality ◽  
Sensory Feedback ◽  
Control Experiment ◽  
Perceptual Bias ◽  
Weight Changes ◽  
Standard Size ◽  
Heaviness Perception ◽  
Brain Mechanism ◽  
Weight Illusion ◽  
Mismatch Theory

Abstract In the size-weight illusion, the smaller object from two equally weighted objects is typically judged as being heavier. One explanation is that the mismatch between the weight expectation based on object size and actual sensory feedback influences heaviness perception. In most studies, the size of an object is perceived before its weight. We investigated whether size changes would influence weight judgement if both would be perceived simultaneously. We used virtual reality to change the size and weight of an object after lifting and asked participants to judge whether the object became lighter or heavier. We found that simultaneous size-weight changes greatly reduced the size-weight illusion to perceptual biases below discrimination thresholds. In a control experiment in which we used a standard size-weight illusion protocol with sequential lifts of small and large objects in the same virtual reality setup, we found a larger, typical perceptual bias. These results show that the size-weight illusion is smaller when size and weight information is perceived simultaneously. This provides support for the prediction mismatch theory explaining the size-weight illusion. The comparison between perceived and expected weight during the lifting phase could be a critical brain mechanism for mediating the size-weight illusion.

scholarly journals Effects of post-training novelty exposure on contextual fear memory: An attempt to translate behavioral tagging to humans

2018 ◽  
Author(s):  
Mason McClay ◽  
Joseph E. Dunsmoor
Keyword(s):  
Virtual Reality ◽  
Time Window ◽  
Critical Time ◽  
Fear Memory ◽  
Contextual Fear Conditioning ◽  
Contextual Fear ◽  
Contextual Fear Memory ◽  
Null Result ◽  
Adult Humans

AbstractIn rodents, poorly formed hippocampal memories can be improved by novelty exploration within a critical time window, in line with the “behavioral tagging” hypothesis. Here, we sought to establish an analogue protocol to investigate if novelty exploration similarly operates to rescue weak hippocampal-dependent memories in humans. Adult humans underwent suboptimal contextual fear conditioning, followed 10 minutes later by open field novelty exploration in immersive 3D virtual reality. Novelty exploration did not improve long-term contextual fear memory, contrary to a behavioral tagging hypothesis. Despite this null result, we suggest further attempts to translate behavioral tagging from rodents to humans is warranted.

scholarly journals Cognitive insight is associated with perceived body weight in overweight and obese adults

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Sharain Suliman ◽  
Leigh L. van den Heuvel ◽  
Sanja Kilian ◽  
Erine Bröcker ◽  
Laila Asmal ◽  
...  
Keyword(s):  
Body Weight ◽  
Cognitive Functioning ◽  
Health Care Professionals ◽  
Weight Perception ◽  
High Body Mass Index ◽  
Healthy Weight ◽  
Weight Changes ◽  
Obese Adults ◽  
Cognitive Insight ◽  
Accurate Perception

Abstract Background Accurate perception of body weight is necessary for individuals with a high body mass index (BMI) to initiate strategies to improve their health status. Furthermore, identifying factors that influence accurate body weight perception can assist in designing appropriate educational and weight management programs. We therefore aimed to investigate whether levels of cognitive functioning and insight influence the ability to correctly judge body weight. Methods One hundred and eighty four overweight and obese adults who participated in a cross- sectional case-control study and were controls in the aforementioned study were included. The study was conducted in Cape Town, South Africa. Demographic, weight-related, neuropsychiatric, neurocognitive and cognitive insight measures were administered. Regression analysis was conducted to determine the factors associated with correct weight perception. Results The final regression model explained 52.3% of variation in accurate perception of body weight and was significant (p ≤ 0. 001). The model correctly classified 79.3% of individuals who were able to correctly and incorrectly judge their weight. Adults with higher BMI, and lower self-certainty, those who reported that they had gained weight in the previous year and those who were told by a healthcare professional to lose or maintain a healthy weight were more likely to correctly judge their weight. Conclusion Some aspects of cognitive insight (self-certainty) but not cognitive functioning were associated with perception of body weight in this sample. Awareness of recent weight changes, higher BMI and advice from of health care professionals were also significantly associated with perception of body weight, while demographic variables were not. Understanding the factors that contribute to the correct perception of weight is important in identifying appropriate health interventions that may address the burden of associated non-communicable diseases in overweight and obese individuals.

Virtual Weight Illusion: Weight Perception of Virtual Objects Using Weight Illusions

2021 ◽  
Author(s):  
Akihiro Maehigashi ◽  
Akira Sasada ◽  
Miki Matsumuro ◽  
Fumihisa Shibata ◽  
Asako Kimura ◽  
...  
Keyword(s):  
Weight Perception ◽  
Virtual Objects ◽  
Weight Illusion ◽  
Weight Illusions

scholarly journals Body Mass Index and Body Weight Perception among a Population of Female Adolescents

2020 ◽  
Vol 8 (E) ◽  
pp. 308-312
Author(s):  
Siham Lghoul ◽  
Mohamed Loukid ◽  
Mohamed Kamal Hilali
Keyword(s):  
Body Mass Index ◽  
Body Weight ◽  
Body Mass ◽  
Weight Perception ◽  
Normal Weight ◽  
Female Adolescents ◽  
Weight Changes ◽  
Cross Sectional ◽  
Body Weight Perception ◽  
Physical Changes

BACKGROUND: Adolescence is associated with many physical changes, it is described as a period when body weight changes and is likely to become worrying for many adolescents. AIM: This study aims to evaluate associations between body weight perception and body mass index (BMI) among a population of female adolescents. METHODS: A cross-sectional school-based study was conducted from February to May 2017 among 12–19 years olds adolescents (n = 415) from high and middle school. BMI for age percentiles was calculated using the WHO AnthroPlus. Body weight perception was determined using an anonymous questionnaire. RESULTS: The prevalence of misconception of body weight was 60%. The prevalence of misconception was positively associated with the participants age (p < 0.001), the occurrence of menarche (p < 0.05), the increasing of BMI (p < 0.001), and with habits diet satisfaction (p < 0.05). Overweighed participants and who’s with normal weight were more likely to perceive their weight incorrectly (p < 0.05). Furthermore, approximately 2.9% of participants underestimated their true body weight and 57.1% overestimated their weight. However, all participants with underweight had correctly perceived their body weight. Logistic regression showed that predictor factors of misconception weight were participant’s age and BMI. CONCLUSION: It is recommended to improve healthy programs in schools aimed at preventing body weight perception and eating problems among adolescents.

scholarly journals Time-Varying Associations Between an Exposure History and a Subsequent Health Outcome: A landmark Approach to Identify Critical Windows.

2021 ◽  
Author(s):  
Maude Wagner ◽  
Francine Grodstein ◽  
Karen Leffondre ◽  
Cécilia Samieri ◽  
Cécile Proust-Lima
Keyword(s):  
Risk Factors ◽  
Health Outcome ◽  
Measurement Errors ◽  
Mixed Model ◽  
Time Window ◽  
Time Windows ◽  
Critical Time ◽  
Cumulative Exposure ◽  
Exposure Measurement ◽  
Exposure History

Abstract Background: Long-term behavioral and health risk factors constitute a primary focus of research on the etiology of chronic diseases. Yet, identifying critical time-windows during which risk factors have the strongest impact on disease risk is challenging. To assess the trajectory of association of an exposure history with an outcome, the weighted cumulative exposure index (WCIE) has been proposed, with weights reflecting the relative importance of exposures at different times. However, WCIE is restricted to a complete observed error-free exposure whereas exposures are often measured with intermittent missingness and error. Moreover, it rarely explores exposure history that is very distant from the outcome as usually sought in life-course epidemiology.Methods: We extend the WCIE methodology to (i) exposures that are intermittently measured with error, and (ii) contexts where the exposure time-window precedes the outcome time-window using a landmark approach. First, the individual exposure history up to the landmark time is estimated using a mixed model that handles missing data and error in exposure measurement, and the predicted complete error-free exposure history is derived. Then the WCIE methodology is applied to assess the trajectory of association between the predicted exposure history and the health outcome collected after the landmark time. In our context, the health outcome is a longitudinal marker analyzed using a mixed model.Results: A simulation study first demonstrates the correct inference obtained with this approach. Then, applied to the Nurses’ Health Study (19,415 women) to investigate the association between body mass index history (collected from midlife) and subsequent cognitive decline (evaluated after age 70), the method identified two major critical windows of association: long before the first cognitive evaluation (roughly 24 to 12 years), higher levels of BMI were associated with poorer cognition. In contrast, adjusted for the whole history, higher levels of BMI became associated with better cognition in the last years prior to the first cognitive interview, thus reflecting reverse causation (changes in exposure due to underlying disease).Conclusions: This approach, easy to implement, provides a flexible tool for studying complex dynamic relationships and identifying critical time windows while accounting for exposure measurement errors.

scholarly journals Clinical Evaluation of Herbal Medicine (ICH-012) in Treating Acute Cerebral Haemorrhage: Safety and Efficacy from 6- to 72-Hour Time Window (CRRICHTrial-II)

2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Qixin Zhang ◽  
Liling Zeng ◽  
Xiuyan Chen ◽  
Yuexiang Zhou ◽  
Baoying Gong ◽  
...  
Keyword(s):  
Herbal Medicine ◽  
Ct Scan ◽  
Time Window ◽  
Rapid Change ◽  
Herbal Medicines ◽  
Critical Time ◽  
Cerebral Haemorrhage ◽  
High Morbidity ◽  
Safety And Efficacy ◽  
Link Type

Background. Hypertensive intracerebral haemorrhage (HICH), which is characterized by rapid change, high morbidity, and mortality, is extremely dangerous. Both medical and surgical treatments lack definitive evidence and remain controversial. A prospective RCT that we have conducted has shown that the usage of the herbal medicine ICH-012 within 6 h of the event may increase the risk of haematoma enlargement and gastrointestinal bleeding. However, the volume of haematoma remains stable after 6 h. Thus, we will increase the time window to the period from 6 to 72 h after onset to evaluate the safety and efficacy of ICH-012 treating ICH (ClinicalTrial.gov ID: NCT03354026). Methods/Design. The CRRICHTrial-II study, a prospective, double-blinded, controlled, multicentre RCT, includes three groups: A, B, and C. Group A patients were treated with 8 herbal medicines (with 2 herbal medicines of Hirudo and Tabanus as well as 6 other combined herbal medicines of Group B) and Group C were placebo. Patients should meet all the inclusion criteria: age between 18 and 80 and diagnosis of HICH by brain CT scan between 6 and 72 h from the onset. The CT scan will be taken at four critical time points: baseline, between 6 and 72h, 24h after onset, and between 10 and 14 days after onset. The drug intervention lasts 10 days, and there is a follow-up visit taken after 90 days. The haematoma enlargement after 24 h onset as demonstrated by CT is the primary outcome. Discussion. A large amount of data from high-quality RCTs is needed for the extensive clinical application of herbal medicine. The CRRICHTrial-II will evaluate the safety and effectiveness of ICH-012 in a safer time window between 6 and 72 h and investigate the possible mechanisms of action and direction of herbal medicine in the haematoma growth after HICH. Trial registration at ClinicalTrial.gov, ID: NCT03354026, is registered on 23rd Nov. 2017.

Sign in / Sign up

Export Citation Format

Share Document