Eye movements as a readout of sensorimotor decision processes

Abstract

Real-world tasks, such as avoiding obstacles, require a sequence of interdependent decisions to reach accurate motor outcomes. Yet, most studies on primate decision making involve simple one-step choices. Here we investigate how sensorimotor decisions develop over time. In a go/no-go interception task human observers (n=42) judged whether a briefly-presented moving target would pass (interception required) or miss (no hand movement required) a strike box while their eye and hand movements were recorded. Go/no-go decision formation had to occur within the first few hundred milliseconds to allow time-critical interception. We found that the earliest time point at which eye movements started to differentiate decision outcome (go vs. no-go) coincided with hand movement onset. Moreover, eye movements were related to different stages of decision making. Whereas higher eye velocity during smooth pursuit initiation (prior to \"whether\" decision) was related to higher go/no-go decision accuracy, faster pursuit maintenance was associated with accurate interception timing (\"when\" decision). These results indicate that pursuit initiation and maintenance are continuously linked to ongoing sensorimotor decision formation.