Can lateral asymmetries in attention explain interfield differences in visual perception?

Speed and accuracy in the discrimination of letters pairs and of unknown faces, and in the response to a light patch, have been tested in two groups of subjects. In one group the stimuli were projected either to the fovea or in the right visual field, while in the other group they were presented either to the fovea or in the right visual field, while in the other group they were presented either to the fovea or in the left visual field. In both groups the three classes of stimuli were alternated in an unpredictable order. There was a decrement of speed of response in the peripheral presentations with respect to the central ones for all types of stimuli. However, the decrement was significantly higher in the left field for the letters and in the right field for the faces, while there were no differences between fields for the light patch. These results do not support an interpretation of lateral asymmetries in perception of letter and faces on the basis of selective pre-exposural attentional mechanisms. © 1974, All rights reserved.