The distribution of visual attention: Evidence based on temporal order judgment (TOJ) task

Abstract

Purpose: The focus of selective attention can be concentrated in areas with different size and specific shapes. In this study we employed a temporal-order-judgment task (TOJ) to explore the differences in the concentration of attentional resources inside and outside the attended area. Methods: The method of constant stimuli was used in two experiments. Subjects' task was to judge which of two sequential letters (“F” or “J”) was presented first (Experiment 1, 2A) or second (Experiment 2B). Randomly, one of the letters was presented inside an area delimited by a frame, an outlined rectangle (6.4° á 1.1°). On each trial the frame was presented horizontally or vertically around the fixation point for 100 ms. One of the letters was presented inside and the other outside the frame. Stimulus onset asynchrony (SOA) between the first and second letter varied by 20, 30, 60, 100 and 200 ms. Results:. In Exp. 1 the point of subjective simultaneity (PSS) was −43ms when the first letter was presented inside the frame and 35 ms when presented outside. In Exp 2, mean PSS values were −28 ms and 33 ms respectively, and did not differ from zero when the frame was absent. Conclusion: The stimulus presented inside the frame had a clear advantage in relation to the stimulus presented outside, independent of whether the subject judged the stimulus as appearing first or second. The results suggest that attentional resources are more concentrated inside a delimited area than outside it.

Footnotes

 Capes, CNPq (CG), NSERC, FQRSC (MvG)