Incidental auditory learning and memory-guided attention: Examining the role of attention at the behavioural and neural level using EEG.

The current study addressed the relation between awareness, attention, and memory, by examining whether merely presenting a tone and audio-clip, without deliberately associating one with other, was sufficient to bias attention to a given side. Participants were exposed to 80 different audio-clips (half included a lateralized pure tone) and told to classify audio-clips as natural (e.g., waterfall) or manmade (e.g., airplane engine). A surprise memory test followed, in which participants pressed a button to a lateralized faint tone (target) embedded in each audio-clip. They also indicated if the clip was (i) old/new; (ii) recollected/familiar; and (iii) if the tone was on left/right/not present when they heard the clip at exposure. The results demonstrate good explicit memory for the clip, but not for tone location. Response times were faster for old than for new clips but did not vary according to the target-context associations. Neuro-electric activity revealed an old-new effect at midline-frontal sites and a difference between old clips that were previously associated with the target tone and those that were not. These results are consistent with the attention-dependent learning hypothesis and suggest that associations were formed incidentally at a neural level (silent memory trace or engram), but these associations did not guide attention at a level that influenced behaviour either explicitly or implicitly.