Wesley, Sanchez, & Reber – CNS 2011
Cognitive depletion has a negative impact on the rate of implicit perceptual-motor sequence learning
Abigail H. Wesley, Daniel J. Sanchez, Paul J. Reber
Ego-depletion theory states that humans possess a limited store of cognitive resources that, when depleted, produce deficits in self-regulation or cognitive control. Depletion effects on implicit learning, which is not thought to require cognitive control, have not previously been reported. However, if depletion reflects transiently lower levels of dopamine, ego-depletion might be associated with slower learning for tasks dependent on dopamine-gated plasticity in cortico-striatal circuits. The relationship between ego-depletion and implicit learning was examined by comparing participants’ levels of cognitive depletion with sequence learning performance. Participants first completed the Stroop Task to assess depletion, measured as the reaction time difference between control and incongruent trials. Participants then performed the Serial Interception Sequence Learning (SISL) task. The SISL task is a perceptual-motor sequence learning task whereby circular cues scroll across a computer screen toward targets, and participants attempt to press the correct key when a cue fits within the target zone. Participants received 2880 trials of training on a covertly embedded 12-item second-order conditional sequence, followed by tests of both implicit and explicit sequence knowledge. Implicit sequence knowledge was assessed as the percent correct difference between performance on the trained sequence and novel sequences. A negative correlation was found between the interference effect and the amount of implicit learning exhibited, with a slightly stronger relationship observed for participants who did not demonstrate explicit knowledge of the sequence. These results show that ego depletion may lead to slower implicit learning, implying this process is not as automatic as previously hypothesized.
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