Despite strong theoretical reasons for assuming that abstract representations organize complex action sequences in terms of subplans (chunks) and sequential positions, we lack methods to directly track such content-independent, hierarchical representations in humans. We applied time-resolved, multivariate decoding analysis to the pattern of rhythmic EEG activity that was registered while participants planned and executed individual elements from pre-learned, structured sequences. Across three experiments, the theta and alpha-band activity coded basic elements and abstract control representations, in particular the ordinal position of basic elements, but also the identity and position of chunks. Further, a robust representation of higher-level, chunk identity information was only found in individuals with above-median working memory capacity, potentially providing a neural-level explanation for working-memory differences in sequential performance. Our results suggest that by decoding oscillatory activity we can track how the cognitive system traverses through the states of a hierarchical control structure.
- Ulrich Mayr
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Human subjects: We obtained informed consent from human subjects. Consent and study procedures were approved by the University of Oregon's Human Subjects Institutional Review Board (Protocol 10272010.016).
- David Badre, Brown University, United States
© 2018, Kikumoto & Mayr
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