Saccadic adaptation depends on object selection: evidence from between- and within-object saccadic eye movements.

The accuracy of saccadic eye movements is maintained by saccadic adaptation. Post-saccadic visual feedback about the error between the target position and the saccade endpoint is crucial to the adaptive process. The present experiments examine the adaptation of saccades that select a new target object (between-object saccades) and that of saccades that would not aim for a selected target but execute a fixed motor vector (within-object saccades). We show that the post-saccadic visual error, induced by the intra-saccadic back step, leads to the adaptation of between-object saccades but not of within-object saccades. Furthermore, between-object saccade adaptation does not transfer to within-object saccades. These results suggest that saccadic adaptation depends on the selection of a precise target object.