Alario, F. 1 , Ostrand, R. 2 , Thoenig, M. 3 & Burle, B. 4
1 Laboratoire de Psychologie Cognitive, Aix-Marseille université & CNRS, Marseille, France
2 Departement of Cognitive Science, University of California, San Diego, USA
3 Department of Economics, Université de Lausanne, Switzerland
4 Laboratoire de Neurobiologie Cognitive, Aix-Marseille université & CNRS, Marseille, France
Cognitive control broadly refers to our ability to adapt behavior to an evolving environment. A paradigmatic manifestation of this ability are adaptation effects in conflict resolution tasks. When participants respond to a visual stimulus carrying conflicting information (e.g. a target arrow and distracting arrows pointing in different directions), latencies are longer than in the absence of such conflict. An adaptation (aka Gratton) effect occurs when the magnitude of the conflict effect in a given trial is modulated by the nature (conflict vs. no conflict) of the preceding trial. We set out to distinguish adaptation to conflict from effects of stimulus or response repetition, and from performance effects (i.e. auto-correlation naturally present in response time series). To do so, we resorted to a verbal Stroop task with eighth different targets and distractors, and we conducted advanced data processing at the single trial level. The results of two experiments show that adaptation occurs for current conflict trials only, in the absence of stimulus or response repetition, and that it lasts several trials. Finally, conflict induced by subliminal distractors did not result in adaptation. These results have consequences for our understanding of the control operations reflected by adaptation effects.