Postal, V. 1 , Copet, P. 2 , Jauregi, J. 3 & Thuilleaux, D. 2
1 Université Bordeaux Segalen, France.
2 Hôpital Marin AP-AH, Hendaye, France
3 University of the Basque Country Psikologia Fakultatea, Donostia, Spain.
Task-switching paradigms are widely used to study executive control. However, standard paradigms may not require active control to switch tasks. We examined voluntary task switching by having subjects choose which task to perform on a series of bivalent stimuli. Instructions were to perform the two tasks equally often and in a random order. The response-to stimulus interval (RSI) was either 100 or 1,000 ms, manipulated between blocks. The aim of this study was to compared this task with the explicit task-cuing procedure on a population presented as having some executive deficit : participants with Prader-Willi Syndrome (SPW).The results showed that the SPW have no deficit on the standard paradigm (except a cognitive slowing) but have performed less well on the voluntary task. The results are interpreted in term of a selective deficit of the switching processes, more precisely as an impairment of the top-down processes and a maintenance of the bottom-up processes.