Task specific coding of actions

The present work explores the idea that actions are represented in a task-specific way. When the task context changes, the representation of one and the same action changes, and there is interference between the previous and the current representation of that action. Such interference was investigated in a dual-task situation using two different choice reaction-time tasks that involved the same set of response alternatives. The basic finding was that when the task context changed, repeating the same response led to costs relative to performing another response. In contrast, when the task context did not change, there were no such costs of response repetition. In the first part of the work, the time course of the interference was explored using a psychological refractory period (PRP) paradigm. Furthermore, it was investigated whether the interference also occurred across different response modalities, indicating interference at the level abstract action representations. In the second part of the work, the functional locus of the interference was further investigated. To disentangle whether interference occurred during response selection or during processes later than response selection (e. g., motor processes or monitoring processes), a change-signal paradigm and a response-grouping paradigm were applied. On the basis of the results, a possible mechanism of action recoding is suggested. It is concluded that the task specificity of action representations should be considered when investigating the mechanisms of action control in humans.