Imaging the spatiotemporal dynamics of covert attention with a pupillometric probing paradigm

We can use a covert form of selective attention to efficiently inspect visual aspects in the periphery without making eye movements. However, it has been a challenge to reveal how covert attention shifts across time and space. Here, we report on a pupillometric orienting method to directly probe and visualize covert shifts of attention between cues and targets. The analysis of the spatiotemporal dynamics of attention-enhanced pupil responsivity to probes, presented around and between cues and targets, indicates that attention shifts across spatial locations between cues and targets despite the absence of interconnected objects guiding attention. Furthermore, current settings allowed to make rough temporal estimates on how long it takes for attention to start moving and for it to arrive at target locations. These findings lay the basis for future research into more detailed estimates of departure and arrival latencies, which may vary depending on shift directions, stimulus designs, and populations.