Temporal dynamics of endogenous attentional modulation without cue awareness

Abstract

Invisible visual stimuli can regulate our broad cognitive performance in the pursuit of current goals. Endogenous spatial attention is an important modulator of cognitive performance, and it can be triggered by unconscious cues. However, how its effect changes with time remains unclear. Here, we show that endogenous attention was triggered by an arrow-cue whose direction participants reported being unaware of but which affected the task performance in a time-dependent manner. Participants were asked to remember the directions of eight Landolt c rings (target memory array) after arrow-cue presentation, which was designed to orient their attention to a certain c ring. Then, we applied a delay, ranging from 83 ms to 1000 ms, between the arrow-cue and the target memory array presentation (the possible delays were equally spaced on a logarithmic scale). The attentional effect was greater for the 83, 183, 250 and 333 ms delays than the other six possible delays. In contrast, its effect was maintained irrespective of the delay when the participants reported being aware of the cue direction. Thus, awareness of arrow-cue direction was necessary to maintain endogenous attentional modulation, and its modulation without arrow-cue direction awareness was limited in a time-dependent manner.