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Jeter un regard sur une phase précoce des traitements visuels

Abstract : The aim of this thesis is to investigate the dynamics of the cognitive processing involved in rapid object recognition in natural scenes. In order to get the fastest behavioral responses, we used a saccadic choice task in which subjects had to initiate saccades as fast as possible toward the image containing the target among two images displayed at the same time on the screen. This protocol first revealed differences in processing times between categories, with an advantage for the detection of human faces. Indeed, when human faces were used as the target, the first selective saccades appeared as early as 100 ms after the apparition of the images ! We were thus interested in the mechanisms allowing such fast detection and showed that a low-level attribute might be used to detect and locate faces in the visual field. In order to understand the nature of the early representation used, we designed two other studies which showed that the fastest saccades were not influenced by contextual information, and were based on relatively coarse information. Finally, I present a simple decision model, based on a latency difference between neuronal populations, which accounts for our experimental results. These results, taken in the perspective of what is known about the neural basis of object recognition, showed that the saccadic choice task, allowing access to an early temporal window, will be a very useful tool of interest for future studies on rapid object recognition.
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Contributor : Catherine Marlot <>
Submitted on : Monday, July 26, 2010 - 2:09:44 PM
Last modification on : Monday, October 19, 2020 - 11:12:09 AM
Long-term archiving on: : Thursday, October 28, 2010 - 5:18:11 PM


  • HAL Id : tel-00505864, version 1



Sébastien Crouzet. Jeter un regard sur une phase précoce des traitements visuels. Sciences du Vivant [q-bio]. Université Paul Sabatier - Toulouse III, 2010. Français. ⟨tel-00505864⟩



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