Speed Facilitation In The Absence Of Enhanced Recognition For Target-Aligned But Irrelevant Stimuli Under Cross-modal Presentations

Speed Facilitation In The Absence Of Enhanced Recognition For Target-Aligned But Irrelevant Stimuli Under Cross-modal Presentations Andrew D. Dewald (adewald@hawaii.edu) Department of Psychology, University of Hawaii at Manoa 2530 Dole Street, Honolulu, HI 96822 Scott Sinnett (ssinnett@hawaii.edu) Department of Psychology, University of Hawaii at Manoa 2530 Dole Street, Honolulu, HI 96822 Abstract An ignored stimulus is later recognized at enhanced levels if it had previously been aligned with a target from a separate task. This has been demonstrated using both visual and auditory presentations. Here we extend these findings to multisensory conditions. Participants were required to detect immediate repetitions in a sound or picture stream while ignoring superimposed words presented in the opposite modality (either written or spoken, respectively), and then underwent a surprise recognition test for these words. Contrary to the previous unisensory examples (Dewald, Sinnett, & Doumas, in press; Dewald & Sinnett, 2012), a significant difference between recognition rates for target-aligned and non-aligned words was not observed. However, a highly significant difference in response latency was observed, with target-aligned words being responded to much more quickly. This finding was robust and observed when the surprise test was presented in either the visual or auditory modalities, as well as across modalities. Key words: Attention, Multimodal Presentation, Response latency, Cross-modal processing. Introduction Investigations of the relationship between attention and perception have demonstrated significant learning enhancements for certain stimuli in the absence of focused attention (Seitz & Watanabe, 2003, 2005; Watanabe, Nanez, & Sasaki, 2001). However, in order to observer these enhancements a number of compulsory prerequisite conditions were required. These included extended exposure rates of unattended stimuli (a random dot motion display) that were presented below threshold (a subset of dots moved coherently and subliminally) and also temporally aligned with a target from an attended secondary task. Under such conditions, enhanced learning performance was observed for the unattended stimuli in later motion discrimination tasks (see, Seitz & Watanabe, 2003, 2005; Watanabe et al., 2001). Curiously however, when presenting the same type of stimuli (coherent motion) under the same conditions, but at levels that are easily perceptible (i.e., suprathreshold), the aforementioned learning enhancements vanish (Tsushima, Sasaki, & Watanabe, 2006; Tsushima, Seitz, & Watanabe 2008). Thus, it appears that the relationship between whether or not learning enhancements occur for irrelevant stimuli is dependent on whether the initial presentation is sub- or suprathreshold. It is important to note that the investigations that collectively posit this idea have exclusively used random-dot, coherent motion displays (Seitz & Watanabe, 2003, 2005; Watanabe et al., 2001; Tsushima et al., 2006; Tsushima et al., 2008). A natural ensuing question, therefore, would be whether these findings apply to stimuli that arguably demand a higher level of processing? Directly addressing this question, Dewald, Sinnett, and Doumas (in press) adapted Seitz and Watanabe’s (2003, 2005, see also, Watanabe et al., 2001) motion detection task to include a high-level irrelevant semantic stimulus (words) in an inattentional blindness paradigm (see Rees et al., 1999 for a similar example of the paradigm). Specifically, participants were required to respond to immediate picture repetitions in a stream of serially presented line drawings, while at the same time ignore a simultaneously presented stream of superimposed words. The irrelevant word stream contained a single, unchanging word aligned with the presence of an immediate picture repetition (i.e., target- aligned) as well as seven additional words that were superimposed over the non-repeated pictures (non-aligned; i.e., analogous to exposure frequencies used by Seitz & Watanabe, 2003). The findings demonstrated that, despite attention being directed away from the task-irrelevant items (i.e., the words), subsequent recognition of these previously irrelevant items was nevertheless enhanced. Critically, this enhancement only occurred for words that had been presented simultaneously with a task-target in the previous task (i.e., target-aligned) when compared to non-aligned irrelevant words. Similar enhancements for target-aligned stimuli have been observed when measuring recognition performance for irrelevant pictures that had appeared with targets (geometric shapes) in a separate task (e.g., the attentional boost effect; see Swallow & Jiang, 2010). Collectively, the findings by both Dewald et al. (in press) and Swallow and Jiang seem to paint a different picture than what was described earlier. That is, explicit presentations lead to an enhancement in recognition performance for previously target-aligned items. This is the exact opposite of the inhibited performance observed when explicit motion presentations were used as the irrelevant stimulus (see Tsushima et al., 2006; Tsushima