It Is Harder Than You Think: On the Boundary Conditions of Exploiting Congruency Cues

Humans are able to anticipate abstract task demands and prepare attentional sets accordingly. A popular method to study this ability is to include explicit cues that signal the required level of cognitive control in conflict tasks (e.g., whether or not word meaning will correspond to the task-relevant font color in a Stroop task). Here, we demonstrate that this ability is more limited than assumed by most theories. Starting from a recent finding that implicit cues on the previous trial do not aid task performance, we demonstrate that these cues remain inefficient even when participants are explicitly instructed about their meaning, when the cue-stimulus interval is prolonged, or when the cues are deterministic and blocked (Experiments 1-4). In fact, the cues sometimes even impaired performance. Extending cue-information into the intertrial interval did not help (Experiment 5), and even though we replicated previous cueing effects using explicit cues in between trials in the vocal Stroop task (Experiment 7), this effect disappeared when using manual responses or presenting the cue in the preceding trial (Experiments 6, 8, and 9), and only benefited congruent responses when the intertrial interval was reduced (Experiment 10). Together, these findings point to important boundary conditions in cued control: The ability to prepare for control demands on a trial-by-trial basis is restricted to situations in which cues are presented alone, and where the task involves a nonarbitrary stimulus-response mapping. We discuss these findings in light of recent theories that emphasize the role of event boundaries and the value of cognitive control.