Exogenous attention during perceptual group formation and dissolution

Under natural viewing conditions, a large amount of information reaches our senses, and the visual system uses attention and perceptual grouping to reduce the complexity of stimuli in order to make real-time perception possible. Prior studies have shown that attention and perceptual grouping operate in synergy; exogenous attention is deployed not only to the cued item, but also to the entire group. Here, we investigated how attention and perceptual grouping operate during the formation and dissolution of groups. Our results showed that reaction times are higher in the presence of perceptual groups than they are for ungrouped stimuli. On the other hand, attentional benefits of perceptual grouping were observed during both the formation and the dissolution of groups. The dynamics were similar during group formation and dissolution, showing a gradual effect that takes approximately half a second to reach its maximum level. In the case of group dissolution, the attentional benefits persisted for about a quarter of a second after dissolution of the group. Taken together, our results reveal the dynamics of how attention and grouping work in synergy during the transient period when groups form or dissolve.