Object-based attention prioritizes working memory contents at a theta rhythm

Abstract

Attention samples spatial positions, visual objects or auditory streams rhythmically. This has been reported for tasks where the attended information was perceptually present. Here we tested whether attentional sampling also applies to internal representations held in working memory. Participants memorized four spatial positions that formed the endpoints of two objects, one of which was cued for a delayed match-non-match test. When uncued positions were probed, participants responded faster to those located on the same object as the cued position than to those located on the other object, revealing object-based attention in working memory. Manipulating the interval between cue and probe revealed that object-based attention oscillated at 6 Hz. Moreover, oscillations showed an antiphase relationship between objects, suggesting that attention sampled them in alternation. The striking similarity between rhythmic sampling of mental representations and perceptual information suggests that attentional sampling is a general mechanism of information processing in human cognition.

No evidence of rhythmic visuospatial attention at cued locations in a spatial cuing paradigm, regardless of their behavioural relevance

“…Our results of an attentional sampling at non-cued locations in the behaviourally relevant cue condition fits well with findings reporting that the 7-to 8-Hz frequency is most often found when attention is undivided and directed to one location only, as found in electrophysiological studies (Busch et al, 2009;Busch & VanRullen, 2010). Curiously, whereas earlier studies found that non-cued locations on the same object and the different object were sampled in an anti-phasic pattern (Fiebelkorn et al, 2013;Peters et al, 2020), we rather found a phase-consistent pattern in this study.…”

“…reaction times) better capture rhythmic variability in behaviour. Both types have been used in rhythmic attention paradigms (Fiebelkorn et al, 2013;Landau & Fries, 2012;Peters et al, 2020). Furthermore, there is still no consensus on the best way to identify peaks in power spectra that result from behavioural time courses.…”

“…Moreover, both studies show low effect sizes for this effect at the cued location. Another study, investigating rhythmic sampling in working memory, did not find any effect at the cued location (Peters et al, 2020). Given the importance of these studies and the relevance for the field, it is crucial to understand whether, and at what frequency, the effects occur at the cued location.…”

Attention Samples Items in Visual Working Memory Rhythmically

“…After a blank delay of 1000 ms we presented a cue for 250 ms that matched the color of either Stimulus A or Stimulus B and indicated which of the two working memory items will be probed with 75% validity. Based on previous studies we hypothesized that the cue would reset rhythmic attentional sampling while still requiring participants to maintain a representation of the un-cued item (Fiebelkorn et al, 2013; Landau & Fries, 2012; Mo et al, 2019; Peters et al, 2018). The cue was followed by a blank screen of variable delay (between 200 ms and 700 ms in steps of 16.6 ms) after which we presented a Probe stimulus for 75 ms that matched either Stimulus A or Stimulus B in color and was oriented slightly clock-wise or counter clock-wise.…”

“…Recent work has begun to extend the rhythmic nature of internal attention directed towards VWM items. Peters et al instructed participants to memorize four dots that defined the endpoints and hence the outlines of 2 objects (Peters et al, 2018). A subsequent retro-cue directed and reset attention to one of these objects.…”