Newborns’ sensitivity to speed changes as a building block for animacy perception

Abstract

The human visual system can discriminate between animate beings vs. inanimate objects on the basis of some kinematic cues, such as starting from rest and speed changes by self-propulsion. The ontogenetic origin of such capability is still under debate. Here we investigate for the first time whether newborns manifest an attentional bias toward objects that abruptly change their speed along a trajectory as contrasted with objects that move at a constant speed. To this end, we systematically manipulated the motion speed of two objects. An object that moves with a constant speed was contrasted with an object that suddenly increases (Experiment 1) or with one that suddenly decreases its speed (Experiment 2). When presented with a single speed change, newborns did not show any visual preference. However, newborns preferred an object that abruptly increases and then decreases its speed (Experiment 3), but they did not show any visual preference for the reverse sequence pattern (Experiment 4). Overall, results are discussed in line with the hypothesis of the existence of attentional biases in newborns that trigger their attention towards some visual cues of motion that characterized animate perception in adults.

Infants' preferences for approachers over repulsers shift between 4 and 8 months of age

“…The present findings are limited by the fact that in our scenario, the approacher moved at the same speed, while the repulser changed speed when the approacher came at a minimum distance from him. Previous studies found that infants’ visual perceptual system is sensitive to acceleration (Frankenhuis et al, 2013), as well as that newborns showed a rudimentary attentional bias toward speed changes, and in particular, toward agents that abruptly change their speed without any contact with other agents (Di Giorgio et al, 2021). Additional research could assess whether 4‐month‐olds show a visual preference for an approacher or a repulser in a scenario in which both agents display speed changes.…”

Spontaneous preference for unpredictability in the temporal contingencies between agents' motion in naive domestic chicks

“…Indeed, human adults attribute higher animacy rankings to objects that change speed and direction [12]. Human newborns preferentially look to an agent that starts to move on its own and changes speed in comparison to an agent moving at a constant speed [13,14]. Similarly, visually naive chicks preferentially imprint on an agent that starts to move on its own [15] and prefer to approach agents that spontaneously alter their speed while in movement [16–18].…”

Fetal imidacloprid causes ASD-like impairment of biological motion perception in neonatal chicks

“…Despite heterogeneous diagnostic phenotypes and genetic backgrounds, autism spectrum disorder (ASD) is primarily characterized by impaired social interactions1,2. Visual predisposition to animate objects typically arises early in life3–6, which is hampered in neonates/juveniles with ASD or its familial risk7–14. Along with genetic factors, exposure to environmental chemical agents, such as anticonvulsant drugs (valproic acid VPA15–18) and environmental pollutants including endocrine disruptors and pesticides during pregnancy could be an ASD risk factor 19–25.…”

“…Pre- attentive processing of biologically relevant stimuli (such as BM and face configuration) is assumed to canalize the subsequent memorization, leading to the adaptive formation of social attachment to specific individuals4. Human neonates typically show an early emergence of BM preference3,5,6, which most non-human animal species do not reveal except newly-hatched domestic chicks29,30. Various non- human animals (zebrafish33, pigeons34, cats35, rats36, baboons37 and chimpanzees38) discriminate BM point-light animations, but only after intensive rewarded training trials; these animals do not spontaneously show BM preference just after birth.…”