Speed of visual attention and localization of motion onset
56.4005, Tuesday, 19-May, 2:45 pm - 6:45 pm, Pavilion
Nika Adamian1, Patrick Cavanagh1; 1Laboratoire Psychologie de la Perception, CNRS & Université Paris Descartes, Paris, France
In the Fröhlich effect, the onset of a moving object's trajectory is perceived further ahead in the direction of motion (Fröhlich, 1923). One hypothesis suggests that upon stimulus presentation the focus of attention is shifted to the stimulus and that the moving stimulus is not visible until attention arrives (Müsseler, Ascherschleben, 1998). However, according to the earlier observations, even if the future location of the stimulus is cued ahead of time, the effect, although smaller, remains significant, suggesting that even when cued to its location, the attention shift to the object was not completed before the motion onset, or that attention cannot fully account for the Fröhlich effect. The aim of the present study was to systematically measure the Fröhlich effect under various cueing conditions and to compare the results with the estimates of attentional latencies. The measurement of the Fröhlich effect was carried out using rotational motion at one of four possible locations with valid, invalid or uninformative peripheral cues for the to-be-tested location. To measure the speed of attentional deployment we presented simultaneously rotating bars at the same four locations, asking the subjects to indicate the angle of the bar they saw on an unexpectedly highlighted stimulus (paradigm adapted from Carlson, Hogendoorn & Verstraten, 2006). Consistent with previous reports, the Fröhlich effect was larger in the uncued condition and the longer attentional latencies to the target location measured in this condition accurately predict this increase. Also consistent with previous results, we still find a Fröhlich effect when validly cued. However, our data reveal that the speed of attentional deployment to the cued location allows attention to reach the cued position well ahead of target onset, suggesting that the Fröhlich effect, while prone to attentional modulation, is not simply the consequence of delayed attentional arrival at the stimulus.