The role of inhibitory control in task switching

Yang, Violet Hye-Won (2010) The role of inhibitory control in task switching. PhD thesis, University of Nottingham.

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Previous research on task switching has been confounded by inhibitory control mechanism and there has been debate on the source of switch costs and how and when the inhibitory control occurs during task switching. In order to circumvent this problem, the thesis aimed to investigate the role of inhibition in task switching by examining switch costs, alternating switch costs and congruency effect in three tasks when two preparation intervals (short and long) are given. Task switching experiments in the present study captured both flexibility (changes in task) and anticipatory control (preparation interval between cue and target) and provided the measurement for inhibitory control, 'backward inhibition' by alternating switch cost. Backward inhibition was manifest in longer reaction times (and/or more errors) to alternating switch trials (ABA) than to double switch trials (CBA). Reaction time and error in the present study also reflected whether the task in the current trials were easy when it requires the same response as the task in the previous trials, i.e., whether the required response were congruent.

The results in the thesis provided the strong evidence for switch costs as one of cognitive control mechanism and it was reduced by the long preparation interval through all the experiments. When the cues were arbitrarily matched for each task, switch costs were increased, suggesting that high working memory load and the effort for interpretation of the cues might cause more additional process during switching tasks. On the other hand, the change of the cue type was insensitive to backward inhibition since there were no significant differences on the size of alternating switch costs. The results imply that the occurrence of backward inhibition is more prone to the type of task you perform and level of congruency.

Item Type: Thesis (University of Nottingham only) (PhD)
Supervisors: Jackson, G.M.
Van Heuven, W.
Subjects: B Philosophy. Psychology. Religion > BF Psychology
Faculties/Schools: UK Campuses > Faculty of Science > School of Psychology
Item ID: 14156
Depositing User: EP, Services
Date Deposited: 23 Apr 2014 13:28
Last Modified: 16 Sep 2016 10:27

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