Some activities can be meaningfully dichotomised as 'cognitive' or 'sensorimotor' in nature-but many cannot. This has radical implications for understanding activity limitation in disability. For example, older adults take longer to learn the serial order of a complex sequence but also exhibit slower, more variable and inaccurate motor performance. So is their impaired skill acquisition a cognitive or motor deficit? We modelled sequence learning as a process involving a limited capacity buffer (working memory), where reduced performance restricts the number of elements that can be stored. To test this model, we examined the relationship between motor performance and sequence learning. Experiment 1 established that older adults were worse at learning the serial order of a complex sequence. Experiment 2 found that participants showed impaired sequence learning when the non-preferred hand was used. Experiment 3 confirmed that serial order learning is impaired when motor demands increase (as the model predicted). These results can be captured by reinforcement learning frameworks which suggest sequence learning will be constrained both by an individual's sensorimotor ability and cognitive capacity.
Bibliographical noteFunding: Rachael Raw was initially funded by a Medical Research Council (MRC) PhD studentship and The Magstim Company Ltd. Analysis and publication was further supported by an MRC Centenary Early Career Post-Doctoral Fellowship awarded to Rachael Raw. The production of this manuscript was also supplemented by an MRC-ESRC grant awarded to Mark Mon-Williams (MR/N024397/1) and an Engineering and Physical Sciences Research Council (EPSRC) grant awarded to Mark Mon-Williams and Matteo Leonetti (EP/R031193/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
- WORKING-MEMORY CAPACITY