The emergence of multisensory systems through perceptual narrowing

The aim of the study was to identify possible sensitive phases in the development of the processing system for human faces. We tested the neural processing of faces in 11 humans who had been blind from birth and had undergone cataract surgery between 2 mo and 14 y of age. Pictures of faces and houses, scrambled versions of these pictures, and pictures of butterflies were presented while event-related potentials were recorded. Participants had to respond to the pictures of butterflies (targets) only. All participants, even those who had been blind from birth for several years, were able to categorize the pictures and to detect the targets. In healthy controls and in a group of visually impaired individuals with a history of developmental or incomplete congenital cataracts, the well-known enhancement of the N170 (negative peak around 170 ms) event-related potential to faces emerged, but a face-sensitive response was not observed in humans with a history of congenital dense cataracts. By contrast, this group showed a similar N170 response to all visual stimuli, which was indistinguishable from the N170 response to faces in the controls. The face-sensitive N170 response has been associated with the structural encoding of faces. Therefore, these data provide evidence for the hypothesis that the functional differentiation of category-specific neural representations in humans, presumably involving the elaboration of inhibitory circuits, is dependent on experience and linked to a sensitive period. Such functional specialization of neural systems seems necessary to archive high processing proficiency.

supporting

confidence: 75%

Sensitive periods for the functional specialization of the neural system for human face processing

Röder

Ley

Shenoy

et al. 2013

“…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).…”

Section: Resultsmentioning

confidence: 99%

Monkey visual behavior falls into the uncanny valley

Steckenfinger

Ghazanfar

2009

Self Cite

129

124

Very realistic human-looking robots or computer avatars tend to elicit negative feelings in human observers. This phenomenon is known as the ''uncanny valley'' response. It is hypothesized that this uncanny feeling is because the realistic synthetic characters elicit the concept of ''human,'' but fail to live up to it. That is, this failure generates feelings of unease due to character traits falling outside the expected spectrum of everyday social experience. These unsettling emotions are thought to have an evolutionary origin, but tests of this hypothesis have not been forthcoming. To bridge this gap, we presented monkeys with unrealistic and realistic synthetic monkey faces, as well as real monkey faces, and measured whether they preferred looking at one type versus the others (using looking time as a measure of preference). To our surprise, monkey visual behavior fell into the uncanny valley: They looked longer at real faces and unrealistic synthetic faces than at realistic synthetic faces.animacy ͉ audiovisual speech ͉ avatar ͉ face processing ͉ human robot interaction

“…It is of interest to consider the role of perceptual narrowing in the capacities observed here. Human and macaque infants possess a broad perceptual tuning at birth that later narrows for socio-ecologically relevant signals (25). Studies with monkeys have reported both narrowing for face perception (27, 5, 7) and broad face-voice dynamics perception in infants (39).…”

Section: Discussionmentioning

confidence: 99%

“…Yet, the cross-species issue is of special interest because it provides information about the properties of individual recognition by testing its adaptability. For instance, in human infants, discrimination of faces is known to specialize during the first year of life for conspecifics or even more drastically for individuals of their own socio-ethnic group (22)(23)(24)(25). However, this faculty can be maintained with longer exposure to the other species or groups (e.g., ref.…”

mentioning

confidence: 99%

Spontaneous voice–face identity matching by rhesus monkeys for familiar conspecifics and humans

Sliwa

Duhamel

Pascalis

et al. 2011

115

101

Recognition of a particular individual occurs when we reactivate links between current perceptual inputs and the previously formed representation of that person. This recognition can be achieved by identifying, separately or simultaneously, distinct elements such as the face, silhouette, or voice as belonging to one individual. In humans, those different cues are linked into one complex conceptual representation of individual identity. Here we tested whether rhesus macaques (Macaca mulatta) also have a cognitive representation of identity by evaluating whether they exhibit cross-modal individual recognition. Further, we assessed individual recognition of familiar conspecifics and familiar humans. In a free preferential looking time paradigm, we found that, for both species, monkeys spontaneously matched the faces of known individuals to their voices. This finding demonstrates that rhesus macaques possess a cross-modal cognitive representation of individuals that extends from conspecifics to humans, revealing the adaptive potential of identity recognition for individuals of socioecological relevance.cross-species | vocal communication | nonhuman primates | picture recognition I n humans, both faces and voices convey information about identity, providing some of the many cues we use to recognize individuals we know (1). The multifaceted nature of identity code suggests that a complex cognitive representation binds semantic information with information of different sensory modalities. In rhesus monkeys, however, it has typically been assessed only via single-modality information. For instance, rhesus monkeys can discriminate between calls of two conspecifics in a playback experiment using a spontaneous habituation-discrimination paradigm (2). They are also able to discriminate faces of two conspecifics in a match-to-sample task (3) and monkey faces or human faces in visual paired comparison tasks (4-6). These observations demonstrate that monkeys can discriminate idiosyncratic characteristics ("individual A is different from B") for their own or other species. However, they do not provide evidence of individual recognition ("this is individual A, this is B"). In comparison with discrimination, individual recognition requires an additional associative level that allows retrieval of information belonging to a specific individual. In rhesus monkeys, coarse recognition processes such as of their own species, kin, gender, reproductive status, or hierarchy are well documented (2, 7-12). However, these rudimentary recognition abilities fail to account for some sophisticated behaviors that are observed in rhesus macaques' societies. In particular, rhesus macaques live in large groups and maintain elaborate social relations involving, e.g., nonkin alliances during aggressive interactions, fight interference, reciprocal support, friendly grooming, and reconciliation (13-15). Such an organization would benefit well from the finest-grain individual recognition based on a cognitive multimodal representation of identity.Individu...