Abstract
Previous event-related potential studies have shown that a speeded auditory task interferes with the deployment of visual-spatial attention (as indexed by the N2pc component) and delays encoding into visual short-term memory (as indexed by the SPCN onset latency). However, it is unclear whether the delay of the SPCN reflects postponement or slowing of encoding in visual short-term memory. Since these previous studies only used visual tasks that required the deployment of visual-spatial attention, it is also unclear whether a delay in encoding would occur in absence of a deployment of visual-spatial attention. The goal of the present study was to investigate these two questions. A tone (T1) was presented, followed by a masked visual target (T2). The inter-stimulus interval between T2 and its mask (T2-mask ISI) was 133, 150, 167, or 183 ms. The T1–T2 stimulus onset asynchrony (SOA) was 300, 650, or 1000 ms. A speeded response was required only for T1. T2 was lateralized in Experiment 1 and presented at fixation in Experiment 2. In both experiments. mean reaction time to T1 as well as T1 accuracy were identical in all conditions. In both experiments, T2 accuracy increased as SOA increased, indicating that encoding into visual short-term memory was delayed during the PRP period even when T2 was presented at fixation. As expected, T2 accuracy increased as ISI increased in both experiments. Importantly, the rate at which T2 accuracy increased across ISI did not vary across SOAs, suggesting that speed of encoding was not affected by concurrent central processing in the auditory task. Conditional analysis based on Task1 difficulty corroborated the analyses based on effects of SOA. In sum, results suggest that access to visual short-term memory is postponed by a concurrent speeded auditory task, whether or not the visual task requires deployment of visual-spatial attention.
Meeting abstract presented at VSS 2012