Repeated-measures ANOVAs with cue type (word vs. picture) and SOA (300 vs. 1000 ms) as factors were conducted on total trial duration, search initiation time, scanning time, and verification time (
Table 1).
For total trial duration, there was a significant main effect of cue type, F(1, 11) = 19.35, MS E = 13215.64, p < 0.005, with faster response times for picture cues than word cues, indicating that search was facilitated by the ability to establish a more precise target template. SOA, however, did not produce a significant main effect, F(1, 11) = 1.57, MS E = 17252.93, p = 0.236, nor was there a significant interaction between cue type and SOA, F(1, 11) = 1.51, MS E = 21816.95, p = 0.246. Thus, SOA failed to influence total trial duration.
For search initiation time, there was no main effect of cue type, F(1, 11) = 0.302, MS E = 553.90, p = 0.59; participants began their search equivalently given a picture or a word cue. There was a significant main effect of SOA, F(1, 11) = 30.64, MS E = 469.24, p < 0.001, with a longer SOA producing quicker search initiation. Cue type and SOA did not interact, F(1, 11) = 2.240, MS E = 213.03, p = 0.163. Search initiation was therefore only affected by SOA and not the specificity of the template.
In contrast to search initiation time, cue type produced a significant main effect on both the scanning and verification epochs. Scanning and verification times were shorter for picture than word cues ( F(1, 11) = 12.64, MS E = 7123.55, p < 0.01, and F(1, 11) = 7.62, MS E = 5079.60, p < 0.05, respectively), demonstrating an advantage for a more precise target template. There was no effect of SOA in either the scanning or verification epochs ( F(1, 11) = 0.43, MS E = 14031.42, p = 0.524, and F(1, 11) = 0.86, MS E = 1854.04, p = 0.373, respectively) and no interaction of cue type and SOA in either epoch ( F(1, 11) = 0.96, MS E = 19258.60, p = 0.348, and F(1, 11) = 0.32, MS E = 1160.88, p = 0.582, respectively). Thus, two epochs of visual search, scanning for the target and verifying that the target had been found, were both facilitated by the more precise target cue, supporting the hypothesis that search in real-world scenes is facilitated by a more precise target template.