Abstract
Visual attention can be allocated in space (spatial attention) or in time (temporal attention). Like spatial attention, temporal attention can either be allocated in accordance with one’s goals (i.e., top-down, endogenous) or triggered by external events (i.e., bottom-up, exogenous). However, some cues of visual spatial attention do not fit this dichotomy perfectly. For instance, a central arrow leads to attention allocation to the location it indicates even when it is not predictive, suggesting that it involves involuntary exogenous processes. Yet, the indicated location can only be extracted based on learned associations, suggesting that top-down processes are also involved. This study examined, for the first time, whether a similar ‘hybrid’ cue can be found for visual temporal attention. The target was the letter T in an upright or inverted orientation, and the task required reporting the target’s orientation. Target onset was preceded by auditory rhythms. We rely on previous demonstrations that isochronous rhythms (i.e., with a fixed inter-onset-interval –IOI) that do not predict target onset improve performance for targets appearing in-sync with the rhythm, suggesting exogenous entrainment of temporal attention to these in-sync points in time. Critically, we also employed asynchronous familiar rhythms as temporal analog of arrows. On the one hand, with asynchronous familiar rhythms expectations regarding the time in which the next event will occur can only be based on past exposure, necessitating the involvement of top-down information. On the other hand, the rhythms we employed did not predict target onset, and therefore did not encourage voluntary attention allocation. We found that asynchronous familiar rhythms, which included pitch variations, could entrain attention even though they were not informative. Thus, this study provides a novel demonstration of hybrid (top-down-exogenous) cueing of visual temporal attention.
Acknowledgement: Israel Science Foundation Grant 1081/13 to YY