The decline of cross-species intersensory perception in human infants

Abstract

Between 6 and 10 months of age, infants become better at discriminating among native voices and human faces and worse at discriminating among nonnative voices and other species' faces. We tested whether these unisensory perceptual narrowing effects reflect a general ontogenetic feature of perceptual systems by testing across sensory modalities. We showed pairs of monkey faces producing two different vocalizations to 4-, 6-, 8-, and 10-month-old infants and asked whether they would prefer to look at the corresponding face when they heard one of the two vocalizations. Only the two youngest groups exhibited intersensory matching, indicating that perceptual narrowing is pan-sensory and a fundamental feature of perceptual development.crossmodal ͉ face processing ͉ multisensory F rom the moment of birth, infants find themselves in a socially rich environment where they see and hear other people. In order for them to have veridical and meaningful social experiences with such people, infants must be able to integrate particular faces and voices by detecting their correspondences. Indeed, a number of studies have shown that, beginning as early as 2 months of age, infants begin to exhibit the ability to perceive face-voice correspondences (1-8). Despite this fact, however, the developmental process underlying intersensory integration of faces and voices, as well as more general intersensory processes, remain poorly understood. Current theoretical views assume either that basic intersensory perceptual abilities are present at birth and become increasingly differentiated and refined over age (9) or that such abilities are not present at birth and only emerge gradually during the first years of life as a result of the child's active exploration of the world (10, 11).Most empirical evidence supports the former, differentiation, view in showing that basic intersensory perceptual abilities are already present in infancy and that as infants grow these abilities change and improve in significant ways (12, 13). For example, young human infants can perceive lower-order intersensory relations based on such attributes as intensity (14), temporal synchrony (15, 16), and duration (17), but do not integrate auditory and visual spatial cues (18). In contrast, older infants can perceive higher-order intersensory relations based on such attributes as affect (6) and gender (3), become capable of learning arbitrary intersensory associations (19) and can integrate auditory and visual spatial cues (18). Findings from studies of underlying neural mechanisms of intersensory integration in cats and rhesus monkeys show a similar pattern. Whereas multisensory cells in the superior colliculus of adult cats and rhesus monkeys integrate auditory and visual cues in spatial localization tasks, these cells do not integrate them in neonatal cats and monkeys (20,21). Together, extant findings suggest a general developmental pattern consisting of the initial emergence of low-level intersensory abilities, a subsequent agedependent refinement and improvement ...

Infants are superior in implicit crossmodal learning and use other learning mechanisms than adults

“…18, 2017; be the neural underpinning of the enhanced sensitivity to crossmodal statistics in development. We 600 further assume in line with the "multisensory perceptual narrowing" idea (Lewkowicz & Ghazanfar,601 2006) that experience narrows down the initial crossmodal connectivity and elaborates the 602 connections which are useful for an individual (Johannsen & Röder, 2014;Lewkowicz, 2014). With an 603 improved tuning of neural networks the learning mode changes towards a larger context dependency 604 to guarantee the small adaptations necessary throughout life.…”

Monkey visual behavior falls into the uncanny valley

“…How such expectations are constructed is not known, but it is likely driven by social experience in both monkeys and humans (26)(27)(28)(29). With further development, synthetic agents (both monkeyand human-like) can be used as a fully controllable actor in experiments investigating the neurobiology of dyadic social interactions (30)(31)(32)(33).…”

Seeing who we hear and hearing who we see

“…As a result, ''much, if not all, of neocortex is multisensory'' (24). By this account, perceptual development does not occur in one sensory modality at a time but is integrated from the start (25).…”