Perception in autism does not adhere to Weber's law

Abstract
Data availability
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Abstract

Perceptual atypicalities are a widely acknowledged but poorly understood feature of autism. We demonstrate here a striking violation of one of the most adaptive psychophysical computations - Weber's law - in high-functioning individuals with autism. JNDs based on the best-fitting psychometric functions were measured for size visual judgments (Exp. 1), weight haptic discrimination (Exp. 2), and illusive perception of weight (brightness-weight illusion; Exp. 3). Results for the typically developed group confirmed Weber's law, demonstrating a linear increase in JNDs with intensity, resulting in constant fractions across intensities. The results for the ASD, in contrast, showed no scaling of JNDs with intensity; instead, fractions decreased linearly with intensity. In striking contrast to its consistency in typical perception, Weber's law does not hold for visual and haptic perception in autism. These robust modulations in psychophysical computations, demonstrated for different domains of perception, suggest a modality-independent, low-level mechanism driving altered perception in autism.

Data availability

Data can be found in https://osf.io/ckmhq/.

The following data sets were generated

1. Hadad B-S
(2018) Weber in Autism
Open Science Framework, ckmhq.

https://osf.io/ckmhq

Article and author information

Author details

Bat-Sheva Hadad

Edmond J Safra Brain Research Center, University of Haifa, Haifa, Israel

For correspondence
bhadad22@gmail.com

Competing interests
The authors declare that no competing interests exist.

"This ORCID iD identifies the author of this article:" 0000-0002-3159-8696
Sivan Schwartz

Department of Psychology, University of Haifa, Haifa, Israel

Competing interests
The authors declare that no competing interests exist.

Funding

Israel Science Foundation (967/14)

Bat-Sheva Hadad

The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.

Ethics

Human subjects: All procedures were approved by the Ethical Committee of the Faculty of Education, University of Haifa (Perceptual Processing in ASD: approval number 016/15). Adults who were students at the University of Haifa received course credit, children received a gift card, and individuals with ASD were paid 50NIS per hour to compensate them for their time.

Copyright

This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.