The present study investigated the functional characteristics of task-sets that were never applied before and were formed only on the basis of instructions. We tested if such task-sets could elicit a task-rule congruency effect, which implies the automatic activation of responses in the context of another task. To this end, a novel procedure was developed that revealed instruction-based task-rule congruency effects in two experiments. Although the effect seems quite general (Experiment 1) it still necessitates the formation of a task-set as it cannot be induced by the mere maintenance of instructions in declarative working memory (Experiment 2). We conclude that a task-set representing only key features of an upcoming task can be formed on the basis of instructions alone to such a degree that it can automatically trigger a response tendency in another task. Implications of our results for the impact of instructions on performance in general, and for the occurrence of task-rule congruency effects in particular, are discussed.Keywords: task-set, task switching, task-rule congruency, instructions INSTRUCTION-BASED TASK-RULE CONGRUENCY EFFECTS 3 Instruction-based task-rule congruency effectsGoal-directed behavior is assumed to be based on task-sets that specify and group the control settings of different task-related processes, such as stimulus identification, response selection, and response execution (e.g., Vandierendonck, Liefooghe, & Verbruggen, 2010).While the functional properties of task-sets have been studied extensively in the taskswitching paradigm (see, Kiesel et al., 2010;Monsell, 2003;Vandierendonck et al., 2010 for reviews), only little is known on how task-sets are formed when the instructions of a particular task are presented. This is surprising because it seems obvious that instructions play an important role, for instance, by indicating which task to perform or how a task must be performed. Accordingly, the present study further investigated the functional characteristics of task-sets formed only on the basis of instructions. We tested if a task-set that is formed on the basis of instructions meant for a particular task that has not yet been executed, can elicit automatic response tendencies despite being irrelevant in the context of another task. This was done by using the task-rule congruency effect. Task-Rule CongruencyThe task-rule congruency effect is a robust finding in task-switching studies that require participants to switch between two tasks (e.g., shape or color judgment) that share stimuli (e.g., colored shapes) and responses (e.g., a left or right response key; see, Kiesel et al., 2010;Monsell, 2003; Vandierendonck et al., 2010 for reviews). Each response thus has two -meanings‖ (e.g., circle and red for the left response and square and green for the right response) and stimuli trigger these two meanings, with one related to the relevant task and the other related to the irrelevant task. The task-rule congruency effect refers to the finding that RTs are shorter when both respo...

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An increasing number of studies have demonstrated that a response in one task can be activated automatically on the basis merely of instructed stimulus-response (S-R) mappings belonging to another task. Such instruction-based response activations are considered to be evidence for the formation of S-R associations on the basis of the S-R mappings for an upcoming, but not yet executed, task. A crucial but somewhat neglected assumption is that instructed S-R associations are formed only under conditions that impose a sufficient degree of task preparation. Accordingly, in the present study we investigated the relation between task preparation and the instruction-based task-rule congruency effect, which is an index of response activation on the basis of instructions. The results from two experiments demonstrated that merely instructed S-R mappings of a particular task only elicit instruction-based response activations when that task is prepared for to a sufficient degree. Implications are discussed for the representation of instructed S-R mappings in working memory.

The feeling of controlling events through one's actions is fundamental to human experience, but its neural basis remains unclear. This 'sense of agency' (SoA) can be measured quantitatively as a temporal linkage between voluntary actions and their external effects. We investigated the brain areas underlying this aspect of action awareness by using theta-burst stimulation to locally and reversibly disrupt human brain function. Disruption of the pre-supplementary motor area (pre-SMA), a key structure for preparation and initiation of a voluntary action, was shown to reduce the temporal linkage between a voluntary key-press action and a subsequent electrocutaneous stimulus. In contrast, disruption of the sensorimotor cortex, which processes signals more directly related to action execution and sensory feedback, had no significant effect. Our results provide the first direct evidence of a pre-SMA contribution to SoA.

In order to test whether or not instructions specifying the stimulus-response (S-R) mappings for a new task suffice to create bindings between specified stimulus and response features, we developed a dual task paradigm of the ABBA type in which participants saw new S-R instructions for the A-task in the beginning of each trial. Immediately after the A-task instructions, participants had to perform a logically independent B-task. The imperative stimulus for the A-task was presented after the B-task had been executed. The present data show that the instructed S-R mappings influence performance on the embedded B-task, even when they (1) have never been practiced, and (2) are irrelevant with respect to the B-task. These results imply that instructions can induce bindings between S- and R-features without prior execution of the task at hand.

Summary Many daily behaviors require us to actively focus on the current task and ignore all other distractions. Yet, ignoring everything else might hinder the ability to discover new ways to achieve the same goal. Here, we studied the neural mechanisms that support the spontaneous change to better strategies while an established strategy is executed. Multivariate neuroimaging analysis showed that before the spontaneous change to an alternative strategy, medial prefrontal cortex (MPFC) encoded information that was irrelevant for the current strategy but necessary for the later strategy. Importantly, this neural effect was related to future behavioral changes: information encoding in MPFC was changed only in participants who eventually switched their strategy and started before the actual strategy change. This allowed us to predict spontaneous strategy shifts ahead of time. These findings suggest that MPFC might internally simulate alternative strategies and sheds new light on the organization of PFC.

Recent research has shown that joint-action effects in a social Simon task provide a good index of action co-representation. The present study aimed to specify the mechanisms underlying joint action by considering trial-to-trial transitions. Using non-social stimuli, we assigned a Simon task to two participants. Each was responsible for only one of two possible responses. This task was performed alone (Individual go/nogo task) and in cooperation with another person who was sitting alongside (Joint go/nogo task). As a further control task, we added a Standard Simon task. Replicating previous findings (Sebanz et al. in Cognition 88:B11-B21, 2003), we found no spatial compatibility effect in the Individual go/nogo task but we did find one in the Joint go/nogo task. A more detailed analysis showed that a sequential modulation of the Simon effect was present in both the Joint and the Individual go/nogo tasks. We found reliable Simon effects in trials following Simon compatible trials not only in the Joint go/nogo task but also to a somewhat smaller extent in the Individual go/nogo task. For both these go/nogo tasks, sequential modulation effects were stronger for nogo/go transitions than for go/go transitions. This suggests that low-level feature binding and repetition mechanisms contribute to the social Simon effect related to the specific requirement not to respond on nogo trials.

When sharing a task with another person that requires turn taking, as in doubles games of table tennis, performance on the shared task is similar to performing the whole task alone. This has been taken to indicate that humans corepresent their partner's task share, as if it were their own. Task co-representation allows prediction of the other's responses when it is the other's turn, and leads to response conflict in joint interference tasks. However, data from our lab cast doubt on the view that task co-representation and resulting response conflict are the only or even primary source of effects observed in task sharing. Recent findings furthermore suggest another potential source of interference in joint task performance that has been neglected so far: Self-other discrimination and conflict related to agent identification (i.e., determining whether it is "my" or the other's turn). Based on these findings we propose that participants might not always co-represent what their partner is supposed to do, but instead co-represent that another agent is responsible for part of the task, and when it is his turn. We call this account the actor corepresentation account.