No intrinsic number bias: Evaluating the role of perceptual discriminability in magnitude categorization

• Type of Material: Article
• Authors: Lauren S. Aulet, Carnegie Mellon University; Stella Lourenco, Emory University
• Language: English
• Date: 2022-07-19
• Publisher: Wiley
• Publication Version: Final Published Version
• Copyright Statement: © 2022 The Authors. Developmental Science published by John Wiley & Sons Ltd.
• License: Creative Commons Attribution 4.0 International
• Final Published Version (URL): https://doi.org/10.1111/desc.13305
• Title of Journal or Parent Work: Developmental Science
• Volume: 26
• Issue: 2
• Start Page: e13305
• Grant/Funding Information: This work was supported by a National Institutes of Health (NIH) institutional training grant (T32 HD071845) to LSA.
• Keywords: area perception; vision; categorization; non-symbolic number; numerical cognition
• Research Categories: Psychology, Cognitive; Biology, Neuroscience

Abstract

Accumulating evidence suggests that there is a spontaneous preference for numerical, compared to non-numerical (e.g., cumulative surface area), information. However, given a paucity of research on the perception of non-numerical magnitudes, it is unclear whether this preference reflects a specific bias towards number, or a general bias towards the more perceptually discriminable dimension (i.e., number). Here, we found that when the number and area of visual dot displays were matched in mathematical ratio, number was more perceptually discriminable than area in both adults and children. Moreover, both adults and children preferentially categorized these ratio-matched stimuli based on number, consistent with previous work. However, when number and area were matched in perceptual discriminability, a different pattern of results emerged. In particular, children preferentially categorized stimuli based on area, suggesting that children's previously observed number bias may be due to a mismatch in the perceptual discriminability of number and area, not an intrinsic salience of number. Interestingly, adults continued to categorize the displays on the basis of number. Altogether, these findings suggest a dominant role for area during childhood, refuting the claim that number is inherently and uniquely salient. Yet they also reveal an increased salience of number that emerges over development. Potential explanations for this developmental shift are discussed.