Both vision-for-perception and vision-for-action follow Weber's law at small object sizes, but violate it at larger sizes

Nicola Bruno, Stefano Uccelli, Eva Viviani, Claudio de Sperati

Research output: Contribution to journalArticlepeer-review

Abstract

According to a previous report, the visual coding of size does not obey Weber's law when aimed at guiding a grasp (Ganel et al., 2008a). This result has been interpreted as evidence for a fundamental difference between sensory processing in vision-for-perception, which needs to compress a wide range of physical objects to a restricted range of percepts, and vision-for-action when applied to the much narrower range of graspable and reachable objects. We compared finger aperture in a motor task (precision grip) and perceptual task (cross modal matching or “manual estimation” of the object's size). Crucially, we tested the whole range of graspable objects. We report that both grips and estimations clearly violate Weber's law with medium-to-large objects, but are essentially consistent with Weber's law with smaller objects. These results differ from previous characterizations of perception-action dissociations in the precision of representations of object size. Implications for current functional interpretations of the dorsal and ventral processing streams in the human visual system are discussed.

Original languageEnglish
Pages (from-to)327-334
Number of pages8
JournalNeuropsychologia
Volume91
DOIs
Publication statusPublished - Oct 1 2016

Keywords

  • Accuracy
  • Action
  • Manual estimation
  • Perception
  • Precision
  • Precision grip
  • Weber's law

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Arts and Humanities (miscellaneous)
  • Cognitive Neuroscience
  • Behavioral Neuroscience

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