Abstract
Working memory (WM) is the ability to hold information in mind over a few seconds and use it flexibly for behaviour. Not all items are represented equally in WM. Attention can be allocated to privilege certain information, perhaps by strengthening the trace between items and their context (i.e. “binding”). The aim of this project was to explore the role of attentional selection for feature-binding in WM. We conducted one behavioural and one EEG experiment to test the hypothesis that selecting one feature in memory automatically brings associated, but redundant, features into a privileged state. For both experiments, participants completed a precision WM task that asked them to recall the angle of one of three oriented, coloured bars after a delay. During the delay, an orthogonal ‘incidental task’ cued a feature of one item (behaviour: colour or location cues, EEG: colour cues only) for a match/non-match judgement. On congruent trials, the item that was incidentally cued was probed during memory recall; on incongruent trials, an uncued item was probed. 21 participants completed the behavioural experiment and 30 participants completed the EEG experiment. Behavioural results from both experiments showed improved performance (precision and response times) for congruent relative to incongruent trials. We propose that attentional selection of an item-feature in WM privileges associated, but currently redundant, features. Neurally, following the incidental cue we found greater contra- than ipsilateral alpha suppression and improved neural decoding of the location where the cued item, relative to uncued items, was originally presented. Bringing the cued colour into the focus of attention may involve auto-associative retrieval of the cued-item location, thereby strengthening the feature-context binding and improving behavioural performance. This is consistent with computational models of WM that retrieve features by pattern completion as well as ‘feature-map’ models where location is an obligatory component of feature-binding.
Acknowledgement: Biotechnology and Biological Sciences Research Council