The psychophysics of bouncing: Perceptual constraints, physical constraints, animacy, and phenomenal causality

In the present study we broadly explored the perception of physical and animated motion in bouncing-like scenarios through four experiments. In the first experiment, participants were asked to categorize bouncing-like displays as physical bounce, animated motion, or other. Several parameters of the animations were manipulated, that is, the simulated coefficient of restitution, the value of simulated gravitational acceleration, the motion pattern (uniform acceleration/deceleration or constant speed) and the number of bouncing cycles. In the second experiment, a variable delay at the moment of the collision between the bouncing object and the bouncing surface was introduced. Main results show that, although observers appear to have realistic representations of physical constraints like energy conservation and gravitational acceleration/deceleration, the amount of visual information available in the scene has a strong modulation effect on the extent to which they rely on these representations. A coefficient of restitution >1 was a crucial cue to animacy in displays showing three bouncing cycles, but not in displays showing one bouncing cycle. Additionally, bouncing impressions appear to be driven by perceptual constraints that are unrelated to the physical realism of the scene, like preference for simulated gravitational attraction smaller than g and perceived temporal contiguity between the different phases of bouncing. In the third experiment, the visible opaque bouncing surface was removed from the scene, and the results showed that this did not have any substantial effect on the resulting impressions of physical bounce or animated motion, suggesting that the visual system can fill-in the scene with the missing element. The fourth experiment explored visual impressions of causality in bouncing scenarios. At odds with claims of current causal perception theories, results indicate that a passive object can be perceived as the direct cause of the motion behavior of an active object

Gazing left, gazing right: exploring a spatial bias in social attention

Faces oriented rightwards are sometimes perceived as more dominant than faces oriented leftwards. In this study, we explored whether faces oriented rightwards can also elicit increased attentional orienting. Participants completed a discrimination task in which they were asked to discriminate, by means of a keypress, a peripheral target. At the same time, a task-irrelevant face oriented leftwards or rightwards appeared at the centre of the screen. The results showed that, while for faces oriented rightwards targets appearing on the right were responded to faster as compared to targets appearing on the left, for faces oriented leftwards no differences emerged between left and right targets. Furthermore, we also found a negative correlation between the magnitude of the orienting response elicited by the faces oriented leftwards and the level of conservatism of the participants. Overall, these findings provide evidence for the existence of a spatial bias reflected in social orienting

Anomalous Perception of Biological Motion in Autism: A Conceptual Review and Meta-Analysis

Despite its popularity, the construct of biological motion (BM) and its putative anomalies in autism spectrum disorder (ASD) are not completely clarified. In this article, we present a meta-analysis investigating the putative anomalies of BM perception in ASD. Through a systematic literature search, we found 30 studies that investigated BM perception in both ASD and typical developing peers by using point-light display stimuli. A general meta-analysis including all these studies showed a moderate deficit of individuals with ASD in BM processing, but also a high heterogeneity. This heterogeneity was explored in different additional meta-analyses where studies were grouped according to levels of complexity of the BM task employed (first-order, direct and instrumental), and according to the manipulation of low-level perceptual features (spatial vs. temporal) of the control stimuli. Results suggest that the most severe deficit in ASD is evident when perception of BM is serving a secondary purpose (e.g., inferring intentionality/action/emotion) and, interestingly, that temporal dynamics of stimuli are an important factor in determining BM processing anomalies in ASD. Our results question the traditional understanding of BM anomalies in ASD as a monolithic deficit and suggest a paradigm shift that deconstructs BM into distinct levels of processing and specific spatio-temporal subcomponents

Intuitive physics and cognitive algebra: A review

tIntroduction. – Intuitive physics explores how people without a formal instruction in physics intuitivelyunderstand physical phenomena. After a general overview of the topics of current research in intuitivephysics and a discussion of current debates, this paper provides an introduction to Information IntegrationTheory (IIT). Objective. – By means of examples, it is shown how IIT can be used to directly compare the algebraicstructure of physical laws and the algebraic structure of cognitive representations of these laws .Method. – The review considers about 40 years of research on the application of IIT in the field of intu-itive physics. Occasionally, reference is also made to intuitive physics studies outside this theoreticalframework. Results. – The reviewed studies highlight four main factors that affect the degree of consistency betweenphysical laws and cognitive algebraic laws: the participants’ age, their familiarity with the event understudy, the type of task, and possible learning processes. Conclusion. – The last part of the article discusses the implications of the results of the reviewed studiesfor the two main current hypotheses on the nature of intuitive physics, namely, that intuitive physicsmay be based on sub-optimal heuristics or may be based on the internalization of physical laws

Algebraic aspects of Bayesian modeling in psychology

Several Bayesian models in perceptual and cognitive psychology show a complex organization that is only partly captured by referring to Bayes rule and the associated concepts of prior, likelihood, and posterior distributions. In this article, an algebraic framework is constructed that may serve as a guide for representing and analyzing the internal organization of these models. The construction begins by defining a comprehensive class of probabilistic structures, called probability kernels, and by focusing on three basic operations on them, called projection, conditioning, and promotion. The expressive power of these operations is then illustrated by showing how suitable combinations of them cover typical moves of Bayesian computations, such as mixing or inducing probability distributions, marginalizing likelihood functions, and Bayes rule itself. As a central finding, we show that a suitable combination of the basic operations gives rise to a binary relation that organizes any complete set of probability kernels as a lattice, and we highlight the peculiarities of this algebraic structure. Lastly, we illustrate the analytic use of the proposed framework by applying it to two Bayesian models from the literature, one concerning spatial vision and the other concerning category representation

Evidence of Weight-Based Representations of Gravitational Motion

A hypothesis gaining increasing popularity is that laypeople’s representations of physical phenomena might be driven by internalized physical laws. In three experiments, we tested if such hypothesis holds true for the representation of gravitational motion. Participants were presented with realistic, real-scale virtual spheres falling vertically downward from about 2 m high. The spheres appeared to be made of either polystyrene or wood. In Experiment 1, participants adjusted the falling motion pattern until it appeared to be natural. In Experiment 2, they compared the perceived naturalness of vertical free falls in a vacuum with the perceived naturalness of more realistic falls characterized by the presence of air drag. In Experiment 3, they estimated the position of the sphere after a variable interval of time from the beginning of the fall. Inconsistently with predictions from physics, results showed that representations of gravitational motion were strongly affected by the implied masses of the falling objects and did not account for air drag. This provides support for the hypothesis of weight-based heuristic representations of gravitational motion against the hypothesis of the internalization of physical laws