Magic for the blind: are auditory tricks impossible?

Many magic tricks rely solely on vision, but there are few, if any, that rely on auditory perception alone. Here, we question why this is so and argue that research focusing on this issue could provide deeper theoretical insights into the similarities and differences between our senses.

Illusions of control: A quasi-experiment comparing skill-based and traditional slot machines.

Background and Aims: Electronic gaming machines (EGMs) are a significant source of gambling spend due to their widespread use. Skill-based gambling machines (SGMs) represent an innovative adaptation, merging EGMs' chance-based rewards with video game-like skills. This study aimed to explore the appeal and behavioural consequences of playing SGMs in comparison to traditional reel-based EGMs, particularly focusing on illusions of control, betting behaviour, and the subjective experience of gamblers. Methods: Participants (N = 1,260) were recruited online and engaged in an online task simulating either an SGM or a reel-based EGM, with outcomes represented to influence their survey compensation. The study examined the effect of SGMs relative to EGMs on bet size, persistence, enjoyment, illusions of control, game immersion, and the influence of demographic and gambling problem severity. Results: SGMs particularly appealed to younger adults, regular EGM players, and people with more gambling problems. Despite identical payout structures, people assigned to play SGM showed greater illusions of control, believing in the influence of skill on game outcomes and that practice could improve results. However, there was no significant difference in overall betting intensity between SGM and EGM players, although specific demographic groups showed faster betting speeds in SGMs. Discussion and Conclusions: SGMs, despite not inherently encouraging higher betting intensity, attract vulnerable groups and create illusions of control, posing new regulatory challenges. The visual and interactive features of SGMs, while appealing, might contribute to these perceptions, indicating a need for careful regulation and further research on their long-term impacts on gambling behaviour and harm.

Perceptual ripening of oranges.

We present a practical example for the phenomenon of color assimilation. We describe the advances in research on color assimilation from von Bezold, to Albers and Munker, and provide a compelling example of the recently described "Confetti-illusion" by Novick. Our research introduces a novel aspect by showing how unripe and greenish looking oranges can be perceived as ripe and vibrantly colored when viewed through an orange net. These findings highlight the significant implications of color assimilation in everyday consumer environments, offering a fresh perspective on how visual perception can be manipulated.

Listening with generative models.

Perception has long been envisioned to use an internal model of the world to explain the causes of sensory signals. However, such accounts have historically not been testable, typically requiring intractable search through the space of possible explanations. Using auditory scenes as a case study, we leveraged contemporary computational tools to infer explanations of sounds in a candidate internal generative model of the auditory world (ecologically inspired audio synthesizers). Model inferences accounted for many classic illusions. Unlike traditional accounts of auditory illusions, the model is applicable to any sound, and exhibited human-like perceptual organization for real-world sound mixtures. The combination of stimulus-computability and interpretable model structure enabled 'rich falsification', revealing additional assumptions about sound generation needed to account for perception. The results show how generative models can account for the perception of both classic illusions and everyday sensory signals, and illustrate the opportunities and challenges involved in incorporating them into theories of perception.

Auditory illusions and Post-traumatic stress disorder: Sound test in a case-control study.

Post-Traumatic Stress Disorder (PTSD) is a prevalent and disabling disorder with a high degree of comorbidity. Clinical studies have focused on hallucinations, which could be associated with the severity of the disorder and treatment resistance. Auditory illusions have received little attention so far, possibly because they are particularly difficult to assess. However, they may impact functioning, and underdiagnosis could impair prognosis. To provide a clearer understanding of PTSD psychopathology, this paper proposes to focus on these auditory illusions. A monocentric case-control study was conducted on 30 subjects with PTSD and 30 controls, based on an original design. False recognitions were estimated during a sound test created with a vocoder. Additionally, differences in emotional valence, dissociation, hyperarousal, and reliving were assessed. The study found that individuals with PTSD experience a higher frequency of auditory illusions compared to healthy controls (65% versus 20%, p < 0.001). Additionally, the emotional valence of these illusions was more negative in individuals with PTSD than in controls. The study also identified a correlation between dissociation symptoms, hyperarousal and reliving with auditory illusions. These findings are in line with neurobiological studies of PTSD, as well as cognitive predictive models, and support the hypothesis of a significant prevalence of auditory illusions in PTSD. Like hallucinations, auditory illusions may be influenced by dissociation. Although these results are preliminary, they suggest a need for further investigation into auditory illusions in PTSD and their effect on prognosis.

Relationship Between Positive Illusions, Psychological Resilience, and Subjective Well-Being in College Students: A New Attempt at Positive Psychology.

Positive Illusion, as an important mechanism of cognitive adaptation in positive psychology, enhances positive information feedback, thereby boosting self-worth. This study involved 803 college students from Shaanxi Province, China, surveyed between March 1 and August 31, 2023. The Positive Illusion, Psychological Resilience, and Subjective Well-Being scales were utilized to examine the characteristics and interrelationships of these constructs through path analysis. The findings indicated that college students' levels of Positive Illusions were generally moderate to low (t = 75.04, p < .001), Psychological Resilience levels were low (t = 129.96, p < .001), and their Subjective Well-Being was generally good (t = 222.33, p < .001). Significant positive correlations were found between Subjective Well-Being and Psychological Resilience (r = 0.48, p < .01); Positive Illusions and Psychological Resilience (r = 0.59, p < .01); and Subjective Well-Being and Positive Illusions (r = 0.49, p < .01). Idealization, Controllability, and Optimism in Positive Illusions partially mediated the relationship between Psychological Resilience and Subjective Well-Being, with mediation effect proportions of 16.13%, 12.43%, and 12.69% respectively. Pathways for enhancing college students' Subjective Well-Being are explored, offering relevant theoretical and practical guidance for mental health.

Toward an explanation of cultural differences in subjective well-being: the role of positive emotion norms and positive illusions.

The present research explores the role of positive emotion norms and positive illusions in explaining the higher subjective well-being observed among Europeans compared to East Asians in Canada. Specifically, we investigate the underlying psychological mechanisms contributing to the prevalence of positive self-views among individuals with European backgrounds, characterized by individualism, versus those with East Asian backgrounds, associated with collectivism. Our study compares Europeans and East Asians in Canada to determine whether cultural norms regarding positive emotions account for the elevated positive self-views and subjective well-being in Europeans. With a sample of 225 participants (112 Europeans and 113 East Asians), our findings reveal significant indirect effects of culture on subjective well-being through positive emotion norms and positive illusions. This study highlights that Europeans, compared to East Asians, believe it is more appropriate to experience and express positive emotions, and this norm influences their positive self-views, subsequently impacting subjective well-being. These findings offer valuable insights into how cultural factors shape subjective well-being across different groups.

Extension of a computational model of a class of orientation illusions.

Polarity-dependent orientation illusions constitute a class of illusions in which the impression of orientation does not depend only on geometrical relations between its elements, but also on the relations between their luminances. Several examples of such figures are presented in the paper. Todorovic (2021a) presented a simple computational model of such phenomena. Simulations of the model indicated that a common feature of the neural basis of these illusions is the presence of certain neural structures called 'oblique clusters'. A limitation of the model was that it used a restricted set of parameters. In this paper a generalization of the model is introduced involving types of receptive fields, their orientation sensitivity and their size or spatial frequency tuning. The simulations of the new model indicated that oblique clusters were present in the reaction patterns under a much wider set of conditions, though not all. The original hypothesis that oblique clusters constituted the neural foundations of impressions of tilt in this class of illusions was vindicated.

The functional role of conscious sensation of movement.

This paper proposes a new framework for investigating neural signals sufficient for a conscious sensation of movement and their role in motor control. We focus on signals sufficient for proprioceptive awareness, particularly from muscle spindle activation and from primary motor cortex (M1). Our review of muscle vibration studies reveals that afferent signals alone can induce conscious sensations of movement. Similarly, studies employing peripheral nerve blocks suggest that efferent signals from M1 are sufficient for sensations of movement. On this basis, we show that competing theories of motor control assign different roles to sensation of movement. According to motor command theories, sensation of movement corresponds to an estimation of the current state based on afferent signals, efferent signals, and predictions. In contrast, within active inference architectures, sensations correspond to proprioceptive predictions driven by efferent signals from M1. The focus on sensation of movement provides a way to critically compare and evaluate the two theories. Our analysis offers new insights into the functional roles of movement sensations in motor control and consciousness.

Age-related changes in the susceptibility to visual illusions of size.

As the global population ages, understanding of the effect of aging on visual perception is of growing importance. This study investigates age-related changes in adulthood along size perception through the lens of three visual illusions: the Ponzo, Ebbinghaus, and Height-width illusions. Utilizing the Bayesian conceptualization of the aging brain, which posits increased reliance on prior knowledge with age, we explored potential differences in the susceptibility to visual illusions across different age groups in adults (ages 20-85 years). To this end, we used the BTPI (Ben-Gurion University Test for Perceptual Illusions), an online validated battery of visual illusions developed in our lab. The findings revealed distinct patterns of age-related changes for each of the illusions, challenging the idea of a generalized increase in reliance on prior knowledge with age. Specifically, we observed a systematic reduction in susceptibility to the Ebbinghaus illusion with age, while susceptibility to the Height-width illusion increased with age. As for the Ponzo illusion, there were no significant changes with age. These results underscore the complexity of age-related changes in visual perception and converge with previous findings to support the idea that different visual illusions of size are mediated by distinct perceptual mechanisms.

Perceptual axioms are irreconcilable with Euclidean geometry.

There are different definitions of axioms, but the one that seems to have general approval is that axioms are statements whose truths are universally accepted but cannot be proven; they are the foundation from which further propositional truths are derived. Previous attempts, led by David Hilbert, to show that all of mathematics can be built into an axiomatic system that is complete and consistent failed when Kurt Gödel proved that there will always be statements which are known to be true but can never be proven within the same axiomatic system. But Gödel and his followers took no account of brain mechanisms that generate and mediate logic. In this largely theoretical paper, but backed by previous experiments and our new ones reported below, we show that in the case of so-called 'optical illusions', there exists a significant and irreconcilable difference between their visual perception and their description according to Euclidean geometry; when participants are asked to adjust, from an initial randomised state, the perceptual geometric axioms to conform to the Euclidean description, the two never match, although the degree of mismatch varies between individuals. These results provide evidence that perceptual axioms, or statements known to be perceptually true, cannot be described mathematically. Thus, the logic of the visual perceptual system is irreconcilable with the cognitive (mathematical) system and cannot be updated even when knowledge of the difference between the two is available. Hence, no one brain reality is more 'objective' than any other.

The inner tube effect.

We describe a novel size illusion in which targets appear to either shrink or grow when enclosed within a narrow tube. The direction of size change is determined by the contrast step between display elements. We first noticed this effect in the context of the dynamic "rocking line" illusion (RLI), but it can also be easily seen in completely static displays. As with the RLI, the overall scale of the display seems to play an important role. We provide an online, interactive demo, enabling the reader to explore the relevant parameter space.

Winning Exposure and Positive Illusions Among Chinese Lottery Gamblers: Moderating Effects of Lottery Winning Experience and Socioeconomic Status.

Positive illusions and winning exposure are key factors leading to problem lottery gambling, but few studies have examined the relationships between them. 402 Chinese lottery gamblers was conducted with the Winning Exposure Questionnaire, the Positive illusion Questionnaire, the Winning Experience Questionnaire, and the Social and Economic Status Questionnaire to investigate the relationship between winning exposure and positive illusions as well as the moderating role of winning experience and socioeconomic status. The results showed that winning exposure can significantly and positively predict the positive illusions (optimism bias, better than average bias, and illusion of control) of lottery gamblers. The highest winning amount and subjective socioeconomic status significantly moderated the relationship between winning exposure and optimism bias. That was to say, for lottery gamblers with smaller maximum winning amount and lower subjective socioeconomic status, the association between winning exposure and optimism bias was stronger. Furthermore, the moderating effect of highest winning amount in the relationship between winning exposure and better than average bias, and the moderating effects of occupational status and subjective socioeconomic status in the relationship between winning exposure and illusion of control were marginally significant.

An attentional approach to geometrical illusions.

It is known for a long time that some drawings composed of points, lines, and areas are systematically misperceived. The origin of these geometrical illusions is still unknown. Here we outline how a recent progress in attentional research contributes to a better understanding of such perceptual distortions. The basic idea behind this approach is that crucial elements of a drawing are differently attended. These changes in the allocation of spatial attention go along with systematic changes in low-level spatial coding. As a result, changes in the perception of spatial extent, angles, positions, and shapes can arise. How this approach can be applied to individual illusions is discussed.

The Motion-Silencing Illusion Depends on Object-Centered Representation.

Motion silencing is a striking and unexplained visual illusion wherein changes that are otherwise salient become difficult to perceive when the changing elements also move. We develop a new method for quantifying illusion strength (Experiments 1a and 1b), and we demonstrate a privileged role for rotational motion on illusion strength compared with highly controlled stimuli that lack rotation (Experiments 2a to 3b). These contrasts make it difficult to explain the illusion in terms of lower-level detection limits. Instead, we explain the illusion as a failure to attribute changes to locations. Rotation exacerbates the illusion because its perception relies upon structured object representations. This aggravates the difficulty of attributing changes by demanding that locations are referenced relative to both an object-internal frame and an external frame. Two final experiments (4a and 4b) add support to this account by employing a synchronously rotating external frame of reference that diminishes otherwise strong motion silencing. All participants were Johns Hopkins University undergraduates.

Illusions of knowledge due to mere repetition.

Repeating information increases people's belief that the repeated information is true. This truth effect has been widely researched and is relevant for topics such as fake news and misinformation. Another effect of repetition, which is also relevant to those topics, has not been extensively studied so far: Do people believe they knew something before it was repeated? We used a standard truth effect paradigm in four pre-registered experiments (total N = 773), including a presentation and judgment phase. However, instead of "true"/"false" judgments, participants indicated whether they knew a given trivia statement before participating in the experiment. Across all experiments, participants judged repeated information as "known" more often than novel information. Participants even judged repeated false information to know it to be false. In addition, participants also generated sources of their knowledge. The inability to distinguish recent information from well-established knowledge in memory adds an explanation for the persistence and strength of repetition effects on truth. The truth effect might be so robust because people believe to know the repeatedly presented information as a matter of fact.

Investigating acoustic numerosity illusions in professional musicians.

Various studies have reported an association between musical expertise and enhanced visuospatial and mathematical abilities. A recent work tested the susceptibility of musicians and nonmusicians to the Solitaire numerosity illusion finding that also perceptual biases underlying numerical estimation are influenced by long-term music training. However, the potential link between musical expertise and different perceptual mechanisms of quantitative estimation may be either limited to the visual modality or universal (i.e., modality independent). We addressed this question by developing an acoustic version of the Solitaire illusion. Professional musicians and nonmusicians listened to audio file recordings of piano and trombone notes and were required to estimate the number of piano notes. The stimuli were arranged to form test trials, with piano and trombone notes arranged in a way to form the Solitaire pattern, and control trials, with randomly located notes to assess their quantitative abilities in the acoustic modality. In the control trials, musicians were more accurate in numerical estimation than nonmusicians. In the presence of illusory patterns, nonmusicians differed from musicians in the esteem of regularly arranged vs. randomly arranged notes. This suggests that the association between long-term musical training and different perceptual mechanisms underlying numerical estimation may not be confined to the visual modality. However, neither musicians nor nonmusicians seemed to be susceptible to the acoustic version of the Solitaire illusion, suggesting that the emergence of this illusion may be stimulus and task-dependent.

Ebbinghaus, Müller-Lyer, and Ponzo: Three examples of bidirectional space-time interference.

Previous studies have shown interference between illusory size and perceived duration. The present study replicated this space-time interference in three classic visual-spatial illusions, the Ebbinghaus, the Müller-Lyer, and the Ponzo illusion. The results showed bidirectional interference between illusory size and duration for all three illusions. That is, subjectively larger stimuli were judged to be presented longer, and stimuli that were presented longer were judged to be larger. Thus, cross-dimensional interference between illusory size and duration appears to be a robust phenomenon and to generalize across a wide range of visual size illusions. This space-time interference most likely arises at the memory level and supports the theoretical notion of a common representational metric for space and time.

The phenomenology of pareidolia in healthy subjects and patients with left- or right-hemispheric stroke.

Pareidolia are perceptions of recognizable images or meaningful patterns where none exist. In recent years, this phenomenon has been increasingly studied in healthy subjects and patients with neurological or psychiatric diseases. The current study examined pareidolia production in a group of 53 stroke patients and 82 neurologically healthy controls who performed a natural images task. We found a significant reduction of absolute pareidolia production in left- and right-hemispheric stroke patients, with right-hemispheric patients producing overall fewest pareidolic output. Responses were categorized into 28 distinct categories, with 'Animal', 'Human', 'Face', and 'Body parts' being the most common, accounting for 72% of all pareidolia. Regarding the percentages of the different categories of pareidolia, we found a significant reduction for the percentage of "Body parts" pareidolia in the left-hemispheric patient group as compared to the control group, while the percentage of this pareidolia type was not significantly reduced in right-hemispheric patients compared to healthy controls. These results support the hypothesis that pareidolia production may be influenced by local-global visual processing with the left hemisphere being involved in local and detailed analytical visual processing to a greater extent. As such, a lesion to the right hemisphere, that is believed to be critical for global visual processing, might explain the overall fewest pareidolic output produced by the right-hemispheric patients.