Ultra-rapid categorisation in non-human primates.

Full Abstract

The visual system of primates is remarkably efficient for analysing information about objects present in complex natural scenes. Recent work has demonstrated that they perform this at very high speeds. In a choice saccade task, human subjects can initiate a first reliable saccadic eye movement response to a target (the image containing an animal) in only 120 ms after image onset. Such fast responses impose severe time constraints if one considers neuronal responses latencies in high-level ventral areas of the macaque monkey. The question then arises: are non-human primates able to perform the task? Two rhesus macaque monkeys (Macaca mulatta) were trained to perform the same forced-choice categorization task as the one used in humans. Both animals performed the task with a high accuracy and generalized to new stimuli that were introduced everyday: accuracy levels were comparable both with new and well-known images (84% vs. 94%). More importantly, reaction times were extremely fast (minimum reaction time 100 ms and median reaction time 152 ms). Given that typical single units onset times in Inferotemporal cortex (IT) are about as long as the shortest behavioural responses measured here, we conclude that visual processing involved in ultra rapid categorizations might be based on rather simple shape cue analysis that can be achieved in areas such as extrastriate cortical area V4. The present paper demonstrates for the first time, that rhesus macaque monkeys (Macaca mulatta) are able to match human performance in a forced-choice saccadic categorisation task of animals in natural scenes.

Author information

Author/s: Girard, P (P); Jouffrais, C (C); Kirchner, C H (CH);

Affiliation: Université de Toulouse, CerCo, UPS, 31062, Toulouse, France. pascal.girard(-atsign-)cerco.ups-tlse.fr

Journal and publication information

Publication Type: Journal Article

Journal: Animal cognition (Anim Cogn), published in Germany. (Language: eng)

Reference: 2008-Jul; vol 11 (issue 3) : pp 485-93

Dates: Created 2008/06/10; Completed 2008/09/16; Revised 2009/02/17;

PMID: 18259787, status: MEDLINE (last retrieved date: 3/9/2009)

Sourced from the National Library of Medicine. Abstract text and other information may be subject to copyright.

Comments and Corrections

ErratumIn: Anim Cogn. 2008 Oct;11(4):727.

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