UC Davis

Attention is the ability to concentrate on relevant events and objects while ignoring distractions. In laboratory settings, studies of top-down voluntary attention often employ paradigms with predictive or instructional cues to direct participants’ attention. However this is not how attention always operates in the real world, as voluntary attention can be guided volitionally, without external cues. The volitional control of attention without external influence is termed “willed attention”. This concept shares terminology with the study of willed motor actions, where motor actions are self-initiated. In line with the research on willed action, willed attention involves participants freely choosing where to direct their focus without external guidance. Here, I present three electrophysiological studies which center on the moment-to-moment neural activity which influences these willful shifts of attention. By studying the EEG signals obtained from humans, I have assessed the transient brain electrical patterns underlying shifts of willed attention in three separate human EEG experiments. First, I review the field of willed attention and relate it to the longstanding work on willed action and free will. Then, I present a study that breaks out of the usual cue-to-target paradigm and has no temporal constraints, allowing participants to shift attention when and where they would like to. Following that, an experiment focused on overt willed attention (with concomitant eye movements) is presented, where participants are given a visual search task with no external guidance, then I assess the electrophysiology preceding the first saccade into the visual search array. The third and final experiment presented here is a study of willed attention to color, where instead of space being the domain of interest, participants are allowed to choose to attend to one of two colors. In this dissertation, I expand the field of willed attention conceptually by relating the prior research conducted to research in surrounding fields, and experimentally by presenting experiments with different constraints and in different domains of vision than previously studied.