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Abstract

During a forty minute adaptation phase, we presented briefly and alternatively a red patch on the left and a green patch on the right of a computer screen and required subjects to perform repeated eye saccades from one patch to the other. In order to measure partial adaptation to the contingency between color change and direction of eye saccade, a test stage involved the successive presentation of two yellow patches, either in the left-right or the right-left order. To measure the color change necessary to obtain subjective equality, the hue of the test patches was manipulated, varying from reddish to greenish yellow. Opposite PSE-shifts were obtained for left-right and right-left eye saccades, being consistent with an adaptation of color judgements on the direction of eye saccades. By manipulating the distance and the respective position of the two patches in the test stage, we showed that the amount of adaptation, as measured by the PSE-shift, was dependant on the size and orientation of the eye saccades but not on the departure and arrival positions of the saccades. This dependency on the properties of eye saccades arguefor an interpretation in sensorimotor terms of the present effect.