Perceptual narrowing continues throughout childhood: Evidence from specialization of face processing.

Face recognition shows a long trajectory of development and is known to be closely associated with the development of social skills. However, it is still debated whether this long trajectory is perceptually based and what the role is of experience-based refinements of face representations throughout development. We examined the effects of short and long-term experienced stimulus history on face processing, using regression biases of face representations towards the experienced mean. Children and adults performed same-different judgments in a serial discrimination task where two consecutive faces were drawn from a distribution of morphed faces. The results show that face recognition continues to improve after 9 years of age, with more pronounced improvements for own-race faces. This increased narrowing with age is also indicated by similar use of stimulus statistics for own-race and other-race faces in children, contrary to the different use of the overall stimulus history for these two face types in adults. Increased face proficiency in adulthood renders the perceptual system less tuned to other-race face statistics. Altogether, the results demonstrate associations between levels of specialization and the extent to which perceptual representations become narrowly tuned with age.

Atypical Impact of Action Effect Delay on Motor Performance in Autism.

Atypical sensory perception and motor impairments are primary features of autism spectrum disorder (ASD) that indicate atypical development and predict social and non-social challenges. However, their link is poorly understood. Sensory perception is often integrated with motor processes when a sensory effect is temporally contiguous with the motor response. Such sensory-motor coupling further improves motor behavior. Previous studies indicate alterations in sensory perception of action-effect temporal contiguity in ASD, which bares the question of how it may impact motor performance. People diagnosed with ASD and typically developed (TD) participants performed a speeded reaction-time task previously established to capture the facilitating impact of action's perceptual effect on motor response selection. The sensitivity of this mechanism to delays in the effect was measured, manipulating the action-effect temporal contiguity in a within-subject design. An immediate action effect (compared to a No-effect condition) facilitated response selection in the TD group. This facilitation effect was evident in the ASD group but did not show the typical sensitivity to the effect delay. While in the TD group, RT was shorter in the short (225ms) compared to the long (675ms) action effect delay condition, this distinguished pattern was absent in the ASD group. The findings provide supporting evidence that atypical motor performance in ASD results, at least in part, from an altered sensory perception of action effect temporal contiguity. We discuss the results in light of the reduced perceptual specialization account in ASD and its potential for undermining adaptive sensorimotor processes.

Weaker face recognition in adults with autism arises from perceptually based alterations.

Face recognition has been shown to be impaired in autism spectrum disorders (ASD). However, it is still debated whether these face processing deficits arise from perceptually based alterations. We tested individuals with ASD and matched typically developing (TD) individuals using a delayed estimation task in which a single target face was shown either upright or inverted. Participants selected a face that best resembled the target face out of a cyclic space of morphed faces. To enable the disentanglement of visual from mnemonic processing, reports were required either following a 1 and 6 second retention interval, or simultaneously while the target face was still visible. Individuals with ASD made significantly more errors than TD individuals in both the simultaneous and delayed intervals, indicating that face recognition deficits in autism are also perceptual rather than strictly memory based. Moreover, individuals with ASD exhibited weaker inversion effects than the TD individuals, on all retention intervals. This finding, that was mostly evident in precision errors, suggests that contrary to the more precise representations of upright faces in TD individuals, individuals with ASD exhibit similar levels of precision for inverted and upright faces, for both simultaneous and delayed conditions. These results suggest that weakened memory for faces reported in ASD may be secondary to an underlying perceptual deficit in face processing.