Double dissociation between perception and action in children.

Previous research has demonstrated a functional dissociation between vision for perception and vision for action. However, the developmental trajectory of this functional dissociation is not well understood. We directly compared the sensitivity of grasping and perceptual estimations within the same experimental design to the real and illusory sizes of objects positioned in the Ponzo illusion display. Two different-sized objects were placed such that the differences between their real sizes and their perceived sizes were pitted against each other. Children aged 5-8 years and adults made perceptual size discriminations and then grasped (action) or estimated (perception) one of the objects based on its perceived size. Consistent with previous results, for the action task, grasping apertures of adults were scaled with the physical differences in the objects' sizes, even in trials where their overt perceptual decisions were deceived by the illusion. In contrast, perceptual estimations were robustly modulated by the illusion. Interestingly, children outperformed adults in their perceptual discriminations but exhibited adult-like behavior in grasping and in perceptual estimations of the objects, demonstrating a dissociation between perception and action. These results suggest that although the two visual functions are not operating at fully mature levels during childhood, some key mechanisms that support a dissociation between these functions are already in place.

Contextual effects on duration perception are modality-specific.

The perception of magnitude, crucial for a mental representation of the physical world, is often subject to significant biases. Many of these biases are similar across sensory modalities, implying a generalized perception of magnitude. At the same time, some physical magnitudes might have a dedicated modality-specific calibration mechanism to enhance perceptual sensitivity. We examined this question of generalized versus modality-specific processes testing between- and within-modalities' contextual effects on the perception of magnitude. In a constant stimuli procedure, a central standard was embedded in shorter and longer contextual standards. These contextual standards were sampled in either a relatively wider or narrower range of durations. Participants were asked to determine which of the two consecutive durations was longer. Better perceptual sensitivity was found for narrower contexts, with stronger effects in trials in which the standard was presented first. Interestingly, narrower context enhanced sensitivity for standards within the same modality but had no effect on standards of another modality. A unidirectional transfer of contextual effects was observed under certain conditions from auditory, the dominant modality in performing temporal judgments, to vision. These results suggest that the perceptual system appears to develop modality-specific calibration mechanisms, most likely, to enhance perceptual sensitivity and maintain sensory specialization. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Interactions of lexical and conceptual representations: Evidence from EEG.

We examined whether meanings automatically activate linguistic forms, and whether these forms affect semantic decisions. Participants were presented sequentially with pairs of pictures and decided whether the objects in the pictures were related. At no point did they name the pictures. The object names of the experimental stimuli were ambiguous either in orthography (homographs), phonology (homophones), or both (homonyms), or unambiguous. We show that the lexical characteristics of the name of the objects affect a semantic decision about real world relations, in an online measure (N400), in addition to offline behavioral measures. We show a dissociation between conceptual and lexical recognition, where an earlier component (N230), was affected by relatedness, but was not sensitive to the lexical characteristics. We interpret this as supporting the hypothesis that semantic recognition occurs before the automatic lexical activation of the object name, but that once linguistic representations are activated, they affect semantic integration.

Intact Utilization of Contextual Information in Speech Categorization in Autism.

Current theories of Autism Spectrum Disorder (ASD) suggest atypical use of context in ASD, but little is known about how these atypicalities influence speech perception. We examined the influence of contextual information (lexical, spectral, and temporal) on phoneme categorization of people with ASD and in typically developed (TD) people. Across three experiments, we found that people with ASD used all types of contextual information for disambiguating speech sounds to the same extent as TD; yet they exhibited a shallower identification curve when phoneme categorization required temporal processing. Overall, the results suggest that the observed atypicalities in speech perception in ASD, including the reduced sensitivity observed here, cannot be attributed merely to the limited ability to utilize context during speech perception.

Individuals with autism show non-adaptive relative weighting of perceptual prior and sensory reliability.

LAY ABSTRACT: Unique perceptual skills and abnormalities in perception have been extensively demonstrated in those with autism for many perceptual domains, accounting, at least in part, for some of the main symptoms. Several new hypotheses suggest that perceptual representations in autism are unrefined, appear less constrained by exposure and regularities of the environment, and rely more on actual concrete input. Consistent with these emerging views, a bottom-up, data-driven fashion of processing has been suggested to account for the atypical perception in autism. It is yet unclear, however, whether reduced effects of prior knowledge and top-down information, or rather reduced noise in the sensory input, account for the often-reported bottom-up mode of processing in autism. We show that neither is sufficiently supported. Instead, we demonstrate clear differences between autistics and neurotypicals in how incoming input is weighted against prior knowledge and experience in determining the final percept. Importantly, the findings tap central differences in perception between those with and without autism that are consistent across identified sub-clusters within each group.

Typical perceptual organization in autism: Perceptual grouping and spatial distortion.

The extensive literature on global-local processing in people with autism spectrum disorder (ASD) has recently shifted from arguing for a processing impairment among those with ASD to positing an attenuated preference for global processing. One suggestion is that the fast extraction of the global gist is less efficient in ASD, in contrast to the superior attention-driven processing of local elements. To examine this claim of attenuated global processing, the present study tested how perceptual grouping affected the global organization of visual scenes, specifically testing the claim of less mandatory, more optional global processing in ASD. Participants judged the distance between grouped and ungrouped elements in displays in which illusory distortions were inherent in configurations exemplifying the Gestalt principles of organization. Results from six experiments manipulating different Gestalt cues showed a consistent pattern, indicating that for individuals with ASD, as for typically developed (TD) individuals, grouping processes are organizational in nature, incorporating the grouping of related elements while parsing these from other unrelated elements. This parsing is accompanied by distortions in the spatial relationships perceived in the visual scene. ASD participants exhibited an overall larger tendency to overestimate the distances, but they also demonstrated typical perceptual organization processes that were robust and mandatory and, as in neurotypicals, affected the perception of the whole scene. Autism Res 2019. © 2019 International Society for Autism Research, Wiley Periodicals, Inc. LAY SUMMARY: It is known that individuals with autism spectrum disorder (ASD) perceive the world in a different way than their typically developed (TD) peers. While TD individuals exhibit strong bias toward processing the global structure of visual scenes, individuals with ASD exhibit enhanced perception of the local elements. We showed that when the local and global levels are not competing, individuals with autism demonstrate robust global organization that operates even when not directly instructed.

Reduced perceptual specialization in autism: Evidence from the other-race face effect.

Emerging accounts of autism suggest that flexible and broadly tuned perceptual representations, presumably resulting from reduced specialization, may underlie atypical perception. Here, we examined the other-race effect (ORE) to study face processing specialization arising from specific experience with own-race faces. Face discrimination was tested for own- and other-race faces in typically developed individuals and in individuals with autism spectrum disorder (ASD). For each race, faces were morphed to vary discrimination difficulty, and orientation was manipulated to examine inversion effects. The ASD group displayed overall lower sensitivity and reduced inversion effects in processing faces. Importantly, the processing advantage for own-race faces was substantially smaller in this group, resulting specifically from the reduced specialization for the own-race faces. Moreover, the typical larger inversion effect for Caucasian faces was not observed in the ASD group; sensitivity to orientation was smaller and equivalent for the two face races. These more broadly tuned representations in autism may account for the overall weaker representations of faces and suggest, more broadly, that a failure in perceptual specialization may underlie atypical perception in autism. (PsycINFO Database Record (c) 2019 APA, all rights reserved).