The instruction-based congruency effect predicts task execution efficiency: Evidence from inter- and intra-individual differences.

In contrast to traditional conflict paradigms, which measure interference from (over)trained associations, recent paradigms have been introduced that investigate automatic interference from newly instructed, but never executed, associations. In these prospective-instruction paradigms, participants receive new task instructions (e.g., if cat press left, if dog press right), but before they have to apply the instructions, they are first presented with another task that measures the automatic interference from the instructed task information. The resulting instruction-based congruency (IBC) effect is assumed to reflect the strength with which instructions are encoded and maintained in view of their future application. If this assumption holds true, the IBC effect should be inversely related to the speed with which the task instructions are eventually executed. To test this hypothesis, we administered a prospective-instruction paradigm to a large sample of 184 participants and observed a negative correlation between the IBC effect and mean reaction time on the instructed task. Similarly, an analysis looking at within-subject variations in the IBC effect and instructed task reaction times showed the same negative relation. Finally, we also present additional analyses suggesting this effect is independent from standard (experience-based) interference effects, and report explorative analyses that tested possible correlations with personality trait questionaires. Together, these findings confirm a key assumption of the IBC effect in prospective-instruction paradigms, and further support the use of this paradigm in instruction research.

Instructed fear stimuli bias visual attention.

We investigated whether stimuli merely instructed to be fear-relevant can bias visual attention, even when the fear relation was never experienced before. Participants performed a dot-probe task with pictures of naturally fear-relevant (snake or spider) or -irrelevant (bird or butterfly) stimuli. Instructions indicated that two pictures (one naturally fear-relevant and one fear-irrelevant) could be followed by an electrical stimulation (i.e., instructed fear). In reality, no stimulation was administered. During the task, two pictures were presented on each side of the screen, after which participants had to determine as fast as possible on which side a black dot appeared. After a first phase, fear was reinstated by instructing participants that the device was not connected but now was (reinstatement phase). Participants were faster when the dot appeared on a location where an instructed fear picture was presented. This effect seemed independent of whether picture content was naturally fear-relevant, but was only found in the first half of each phase, suggesting rapid extinction due to the absence of stimulation, and rapid re-evaluation after reinstatement. A second experiment similarly showed that instructed fear biases attention, even when participants were explicitly instructed that no stimulation would be given during the dot-probe task. Together, these findings demonstrate that attention can be biased towards instructed fear stimuli, even when these fear relations were never experienced. Future studies should test whether this is specific to fear, or can be observed for all instructions that change the relevance of a given stimulus.