Behavioral measures of decision making are usually limited to observations of decision outcomes. In the present study, we made use of the fact that oculomotor and sensory selection are closely linked to track oculomotor decision making before oculomotor responses are made. We asked participants to make a saccadic eye movement to one of two memorized target locations and observed that visual sensitivity increased at both the chosen and the non-chosen saccade target locations, with a clear bias towards the chosen target. The time course of changes in visual sensitivity was related to saccadic latency, with the competition between the chosen and non-chosen targets resolved faster before short latency saccades. On error trials, we observed an increased competition between the chosen and non-chosen targets. Moreover, oculomotor selection and visual sensitivity were influenced by top-down and bottom-up factors as well as by selection history and predicted the direction of saccades. Our findings demonstrate that saccade decisions have direct visual consequences and show that decision making can be traced in the human oculomotor system well before choices are made. Our results also indicate a strong association between decision making, saccade target selection and visual sensitivity.
- spatial attention
- working memory
- decision making
- Copyright © 2016, Journal of Neurophysiology