Journal Article

Does Subitizing Reflect Numerical Estimation?

Revkin, Susannah K., Dehaene, Stanislas, Piazza, Manuela, Izard, Véronique, Cohen, Laurent

2008

Overview

Subitizing is the rapid and accurate enumeration of small sets (up to 3--4 items). Although subitizing has been studied extensively since its first description about 100 years ago, its underlying mechanisms remain debated. One hypothesis proposes that subitizing results from numerical estimation mechanisms that, according to Weber's law, operate with high precision for small numbers. Alternatively, subitizing might rely on a distinct process dedicated to small numerosities. In this study, we tested the hypothesis that there is a shared estimation system for small and large quantities in human adults, using a masked forced-choice paradigm in which participants named the numerosity of displays taken from sets matched for discrimination difficulty; one set ranged from 1 through 8 items, and the other ranged from 10 through 80 items. Results showed a clear violation of Weber's law (much higher precision over numerosities 1--4 than over numerosities 10--40), thus refuting the single-estimation-system hypothesis and supporting the notion of a dedicated mechanism for apprehending small numerosities.

• Publisher: Blackwell Publishing,SAGE Publications,SAGE PUBLICATIONS, INC,Association for Psychological Science
• Subject: Adolescent / Adult / Adults / Calibration / Choice Behavior - physiology / City squares / Cognition & reasoning / Cognitive development / Cognitive models / Cognitive science / Data ranges / Discrimination / Discrimination (Psychology) - physiology / Enumeration / Error rates / Estimate reliability / Estimating techniques / Estimation / Experimentation / Female / Humans / Hypotheses / Law / Male / Mathematics / Naming conventions / Numeration systems / Perceptual Masking - physiology / Photic Stimulation - methods / Problem Solving - physiology / Psychological Theory / Psychology / Range errors / Reaction Time - physiology / Social psychology / Sociological analysis / Task Performance and Analysis / Time Factors / Visual Perception - physiology / Weber Fechner law