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Animal Cognition May 2024Optical illusions have long been used in behavioural studies to investigate the perceptual mechanisms underlying vision in animals. So far, three studies have focused on...
Optical illusions have long been used in behavioural studies to investigate the perceptual mechanisms underlying vision in animals. So far, three studies have focused on ungulates, providing evidence that they may be susceptible to some optical illusions, in a way similar to humans. Here, we used two food-choice tasks to study susceptibility to the Müller-Lyer and Delboeuf illusions in 17 captive individuals belonging to four ungulate species (Lama guanicoe, Lama glama, Ovis aries, Capra hircus). At the group level, there was a significant preference for the longer/larger food over the shorter/smaller one in control trials. Additionally, the whole group significantly preferred the food stick between two inward arrowheads over an identical one between two outward arrowheads in experimental trials of the Müller-Lyer task, and also preferred the food on the smaller circle over an identical one on the larger circle in the experimental trials of the Delboeuf task. Group-level analyses further showed no significant differences across species, although at the individual level we found significant variation in performance. Our findings suggest that, in line with our predictions, ungulates are overall susceptible to the Müller-Lyer and the Delboeuf illusions, and indicate that the perceptual mechanisms underlying size estimation in artiodactyls might be similar to those of other species, including humans.
Topics: Animals; Camelids, New World; Optical Illusions; Female; Male; Goats; Size Perception; Sheep
PubMed: 38789595
DOI: 10.1007/s10071-024-01878-2 -
Nature Communications Apr 2024Brightness illusions are a powerful tool in studying vision, yet their neural correlates are poorly understood. Based on a human paradigm, we presented illusory drifting...
Brightness illusions are a powerful tool in studying vision, yet their neural correlates are poorly understood. Based on a human paradigm, we presented illusory drifting gratings to mice. Primary visual cortex (V1) neurons responded to illusory gratings, matching their direction selectivity for real gratings, and they tracked the spatial phase offset between illusory and real gratings. Illusion responses were delayed compared to real gratings, in line with the theory that processing illusions requires feedback from higher visual areas (HVAs). We provide support for this theory by showing a reduced V1 response to illusions, but not real gratings, following HVAs optogenetic inhibition. Finally, we used the pupil response (PR) as an indirect perceptual report and showed that the mouse PR matches the human PR to perceived luminance changes. Our findings resolve debates over whether V1 neurons are involved in processing illusions and highlight the involvement of feedback from HVAs.
Topics: Animals; Neurons; Primary Visual Cortex; Mice; Photic Stimulation; Male; Humans; Optogenetics; Female; Visual Perception; Illusions; Optical Illusions; Mice, Inbred C57BL; Pupil; Visual Cortex
PubMed: 38653975
DOI: 10.1038/s41467-024-46885-6 -
BioRxiv : the Preprint Server For... Apr 2024We reliably judge locations of static objects when we walk despite the retinal images of these objects moving with every step we take. Here, we showed our brains solve...
We reliably judge locations of static objects when we walk despite the retinal images of these objects moving with every step we take. Here, we showed our brains solve this optical illusion by adopting an allocentric spatial reference frame. We measured perceived target location after the observer walked a short distance from the home base. Supporting the allocentric coding scheme, we found the intrinsic bias , which acts as a spatial reference frame for perceiving location of a dimly lit target in the dark, remained grounded at the home base rather than traveled along with the observer. The path-integration mechanism responsible for this can utilize both active and passive (vestibular) translational motion signals, but only along the horizontal direction. This anisotropic path-integration finding in human visual space perception is reminiscent of the anisotropic spatial memory finding in desert ants , pointing to nature's wondrous and logically simple design for terrestrial creatures.
PubMed: 38645085
DOI: 10.1101/2023.03.22.533725 -
Vision Research Jun 2024Recent studies have revealed that pupillary response changes depend on perceptual factors such as subjective brightness caused by optical illusions and luminance....
Recent studies have revealed that pupillary response changes depend on perceptual factors such as subjective brightness caused by optical illusions and luminance. However, the manner in which the perceptual factor that is derived from the glossiness perception of object surfaces affects the pupillary response remains unclear. We investigated the relationship between the glossiness perception and pupillary response through a glossiness rating experiment that included recording the pupil diameter. We prepared general object images (original) and randomized images (shuffled) that comprised the same images with randomized small square regions as stimuli. The image features were controlled by matching the luminance histogram. The observers were asked to rate the perceived glossiness of the stimuli presented for 3,000 ms and the changes in their pupil diameters were recorded. Images with higher glossiness ratings constricted the pupil size more than those with lower glossiness ratings at the peak constriction of the pupillary responses during the stimulus duration. The linear mixed-effects model demonstrated that the glossiness rating, image category (original/shuffled), variance of the luminance histogram, and stimulus area were most effective in predicting the pupillary responses. These results suggest that the illusory brightness obtained by the image regions of high-glossiness objects, such as specular highlights, induce pupil constriction.
Topics: Humans; Pupil; Male; Female; Photic Stimulation; Young Adult; Adult; Visual Perception; Optical Illusions; Contrast Sensitivity
PubMed: 38579405
DOI: 10.1016/j.visres.2024.108393 -
Scientific Reports Mar 2024Perceptual grouping is impaired following mild traumatic brain injury (mTBI). This may affect visual size perception, a process influenced by perceptual grouping...
Perceptual grouping is impaired following mild traumatic brain injury (mTBI). This may affect visual size perception, a process influenced by perceptual grouping abilities. We conducted two experiments to evaluate visual size perception in people with self-reported history of mTBI, using two different size-contrast illusions: the Ebbinghaus Illusion (Experiment 1) and the Müller-Lyer illusion (Experiment 2). In Experiment 1, individuals with mTBI and healthy controls were asked to compare the size of two target circles that were either the same size or different sizes. The target circles appeared by themselves (no-context condition), or were surrounded by smaller or larger circles (context condition). Similar levels of accuracy were evident between the groups in the no-context condition. However, size judgements by mTBI participants were more accurate in the context condition, suggesting that they processed the target circles separately from the surrounding circles. In Experiment 2, individuals with mTBI and healthy controls judged the length of parallel lines that appeared with arrowheads (context condition) or without arrowheads (no context condition). Consistent with Experiment 1, size judgements by mTBI participants were more accurate than size judgements by control participants in the context condition. These findings suggest that mTBI influences size perception by impairing perceptual grouping of visual stimuli in near proximity.
Topics: Humans; Illusions; Optical Illusions; Brain Concussion; Visual Perception; Size Perception; Judgment
PubMed: 38499578
DOI: 10.1038/s41598-024-56713-y -
BMC Psychology Mar 2024Humans are typically inept at evaluating their abilities and predispositions. People dismiss such a lack of metacognitive insight into their capacities while even...
Humans are typically inept at evaluating their abilities and predispositions. People dismiss such a lack of metacognitive insight into their capacities while even enhancing (albeit illusorily) self-evaluation such that they should have more desirable traits than an average peer. This superiority illusion helps maintain a healthy mental state. However, the scope and range of its influence on broader human behavior, especially perceptual tasks, remain elusive. As belief shapes the way people perceive and recognize, the illusory self-superiority belief potentially regulates our perceptual and metacognitive performance. In this study, we used hierarchical Bayesian estimation and machine learning of signal detection theoretic measures to understand how the superiority illusion influences visual perception and metacognition for the Ponzo illusion. Our results demonstrated that the superiority illusion correlated with the Ponzo illusion magnitude and metacognitive performance. Next, we combined principal component analysis and cross-validated regularized regression (relaxed elastic net) to identify which superiority components contributed to the correlations. We revealed that the "extraversion" superiority dimension tapped into the Ponzo illusion magnitude and metacognitive ability. In contrast, the "honesty-humility" and "neuroticism" dimensions only predicted Ponzo illusion magnitude and metacognitive ability, respectively. These results suggest common and distinct influences of superiority features on perceptual sensitivity and metacognition. Our findings contribute to the accumulating body of evidence indicating that the leverage of superiority illusion is far-reaching, even to visual perception.
Topics: Humans; Metacognition; Optical Illusions; Bayes Theorem; Visual Perception; Diagnostic Self Evaluation
PubMed: 38429795
DOI: 10.1186/s40359-024-01625-9 -
Journal of the American Heart... Jan 2024
Topics: Humans; Atrial Appendage; Pilot Projects; Left Atrial Appendage Closure; Tomography, Optical Coherence; Illusions; Stroke
PubMed: 38156595
DOI: 10.1161/JAHA.123.032974 -
Experimental Psychology Jul 2023An object appears to move at higher speed than another equally fast object when brief nonspatial tones coincide with its changes in motion direction. We refer to this...
An object appears to move at higher speed than another equally fast object when brief nonspatial tones coincide with its changes in motion direction. We refer to this phenomenon as the beep-speed illusion (Meyerhoff et al., 2022, , , 104978). The origin of this illusion is unclear; however, attentional explanations and potential biases in the response behavior appear to be plausible candidates. In this report, we test a simple bias explanation that emerges from the way the dependent variable is assessed. As the participants have to indicate the faster of the two objects, participants possibly always indicate the audio-visually synchronized object in situations of perceptual uncertainty. Such a response behavior potentially could explain the observed shift in perceived speed. We therefore probed the magnitude of the beep-speed illusion when the participants indicated either the object that appeared to move faster or the object that appeared to move slower. If a simple selection bias would explain the beep-speed illusion, the response pattern should be inverted with the instruction to indicate the slower object. However, contrary to this bias hypothesis, illusion emerged indistinguishably under both instructions. Therefore, simple selection biases cannot explain the beep-speed illusion.
Topics: Humans; Illusions; Optical Illusions; Selection Bias; Motion Perception; Attention; Cognition
PubMed: 38105748
DOI: 10.1027/1618-3169/a000594 -
Heliyon Nov 2023According to research, it has been suggested that individuals who are affected by depression could potentially engage in the creation and experience emotional advantages...
UNLABELLED
According to research, it has been suggested that individuals who are affected by depression could potentially engage in the creation and experience emotional advantages relating to positive events directed towards the past or future, with the condition that they are provided with suitable mental imagery techniques. The main aim of this study was to assess the impact of utilizing positive imagery, specifically through the utilization of photographs featuring loved ones, on mood states and suicidal ideation among individuals diagnosed with depression and exhibiting suicidal tendencies. This randomized, double-blind, controlled crossover trial was conducted among 78 hospitalized depressive patients at three psychiatric services between April and August 2019. The patients participated in four individual picture-viewing sessions on four consecutive days. The four categories of pictures were included: loved ones, neutral faces of strangers, natural landscapes, and optical illusions. Directly prior to and immediately following the observation of the visual stimuli (photographs), the Brunel Mood Scale (BRUMS) and the Beck Scale for Suicide Ideation (BSSI) were completed by the patients. Repeated measures ANOVAs conducted in this study revealed a significant main effect of time on ratings of tension, depression, fatigue, vigor, calmness, and happiness (P values < 0.001). Additionally, statistically significant interactions were identified between picture category and time in relation to the variables of tension, depression, fatigue, vigor, calmness, and happiness (P values < 0.001). The analysis did not reveal a significant main effect of time on ratings of anger, confusion, and suicidal ideation (P values > 0.05). Likewise, the interaction between picture category and time did not yield significant results for the variables of anger, confusion, and suicidal ideation (P values > 0.05). The positive imagery procedure using the presentation of loved ones' photos showed beneficial effects on the mood states of depressed patients. The findings of this study suggest that incorporating a greater emphasis on positive imagery within the context of clinical depression may offer potential advantages. This highlights the potential for novel opportunities in the treatment of depression.
TRIAL REGISTRATION
The study has been registered in the Iranian Registry of Clinical Trials (registration number: IRCT20180808040744N1; first registration date: December 22, 2018; website: https://en.irct.ir/trial/33186).
PubMed: 38058624
DOI: 10.1016/j.heliyon.2023.e22312 -
IScience Dec 2023The neural and computational mechanisms underlying visual motion perception have been extensively investigated over several decades, but little attempt has been made to...
The neural and computational mechanisms underlying visual motion perception have been extensively investigated over several decades, but little attempt has been made to measure and analyze, how human observers perceive the map of motion vectors, or optical flow, in complex naturalistic scenes. Here, we developed a psychophysical method to assess human-perceived motion flows using local vector matching and a flash probe. The estimated perceived flow for naturalistic movies agreed with the physically correct flow (ground truth) at many points, but also showed consistent deviations from the ground truth (flow illusions) at other points. Comparisons with the predictions of various computational models, including cutting-edge computer vision algorithms and coordinate transformation models, indicated that some flow illusions are attributable to lower-level factors such as spatiotemporal pooling and signal loss, while others reflect higher-level computations, including vector decomposition. Our study demonstrates a promising data-driven psychophysical paradigm for an advanced understanding of visual motion perception.
PubMed: 38025782
DOI: 10.1016/j.isci.2023.108307