Which duration of postsaccadic slowing identifies anticipatory saccades during smooth pursuit eye movements?

Increased frequency of anticipatory saccades during smooth pursuit eye move ments is a potential marker of genetic risk for schizophrenia. Postsaccadic slowing criteria are used to separate anticipatory from other types of sac cades. However, the necessary duration of slowed pursuit required to identi fy an anticipatory saccade remains undetermined. We explored the effect of various postsaccadic slowing duration criteria on effect size in a comparis on of younger and older schizophrenic and normal adults. For large anticipa tory saccades, varying the duration of postsaccadic slowing criteria did no t notably change effect size. For smaller leading saccades, a limited 50-ms duration postsaccadic slowing criterion produced the largest effect size ( 1.54), and maintained a similar effect size across a broad age range. Leadi ng saccades with a limited duration postsaccadic slowing criteria are a pos sible marker of genetic risk for schizophrenia.