Attentional Window Affects Audiovisual Capture Figure 1. Example of the search display used in the present study. Participants were asked to do a letter matching task determining whether the target letter (i.e. the letter S or H) was the same or different letter as the cue letter, which was also an S or H.In the diffuse attentional window condition, this cue was a large letter. In the focused attentional window condition, this cue was a small letter. doi:10.1371/journal.pone.0039137.g001 eight small-cue blocks in counterbalanced, alternating order, preceded by two practice blocks. In Experiment 2, participants received four large cue blocks and four small cue blocks in a counterbalanced, alternating order, preceded by two practice Figure 2. Correct mean reaction time (RT) as a function of a focused mode (small cue) or a diffuse mode (large cue). Note that the RT reflects the time to respond to the visual target from the presentation of first target color change. doi:10.1371/journal.pone.0039137.g002 blocks. Participants were informed about the size of the cue prior to each block, and received feedback about their overall mean accuracy and overall RT after each block. Results and Discussion The RT results are presented in Figure 2. RT data from practice blocks and erroneous trials were excluded. RTs and Errors were subjected to a repeated measures univariate analysis of variance (ANOVA) with set size (24 vs. 48) and cue size (small vs. large) as within-subjects variables. RT data. On average, RTs increased with increasing set size, F(1, 9) = 22.2, p = .001. Importantly, RTs were faster when the cue was large (2,035 ms) than when the cue was small (2,262 ms), F(1, 9) = 9.3, p = .01. The interaction between cue size and set size was not reliable (F,1). Error data. Overall mean error rate was 6.4%. The main effect of set size was not reliable, F(1, 9) = 3.1, p = .110. Participants made less errors when the cue was large (5.3%) than when the cue was small (6.6%), F(1, 9) = 9.3, p = .01. The interaction was not reliable (F,1). Responses to audiovisual events were faster and more accurate when attention was diffuse (large cue) than when attention was focused (small cue) at the center of the screen (as induced by the size of the cue). This is consistent with our notion that the size of the visual attentional window affects audiovisual integration. However, an alternative explanation for the better performance when attention is diffusely spread across the visual field is that it may be easier to process a large letter than a small letter. In a control experiment we tested whether a large cue may be processed more quickly than a small cue. To control for this alternative explanation, we replicated the experiment, except that participants (N = 8; 5 female; mean age 25.1 years; range 18–34 years) were asked to respond as fast as possible to the identity (S or H) of the cue, by pressing the corresponding (S or H) key. Furthermore, the tone was always absent. There was no significant cue size effect on RTs and Errors, t(7) = 1.6, p = .151, and t(7),.624, p = .553, respectively. If anything, performance was better when the cue was small (496 ms; 3.7% errors) than when PLoS ONE | www.plosone.org 3 July 2012 | Volume 7 | Issue 7 | e39137