Difficulté de sélection perceptive et sémantique liée au vieillissement cognitif

This work took place within tipper's negative priming paradigm. In a study with two age groups (young and older adults), Connelly and Hasher (5) have measured the identity negative priming, the location negative priming and the « identity and location » negative priming. They used a simple material (letters). For these authors, the young people showed the negative priming effect in all the conditions, but the older people showed this effect only in location and in « identity and location » conditions, but there was no effect in identity condition. Hence, there is a dissociation between identity and location in the older adults group. Our work replicated the procedure of Connelly and Hasher using material presenting semantic (words) and perceptive selection difficulties. Our results were not consistent with the results of the authors. For the two age groups, the « location » and « identity and location » conditions were computed statistically faster than the « identity » condition, and there was no difference in the reaction times between the « location » and « identity and location » conditions. In the young adults group, even if an identity negative priming was obtained, there was no effect in the « location » and « identity and location » conditions (in comparison with a control condition). This led us to conclude is the existence of a dissociation between identity and location for the young adults. In the older adults group, we obtained positive priming in the « identity and location » condition, and no effect in the other conditions. Moreover, the reaction times in the « location » and « identity and location » conditions were faster than in the identity condition. We think about a dissociation between identity and location in the older group. Our data led us to conclude in the existence of a dissociation between identity and location, not only for the older adults, but also for the young adults. Our conclusion agrees with the explanations given by the authors regarding the neurological system ; with the existence of two neuronal pathways, one for the identity and the other for the location. We explain the negative priming effect obtained in the young adults group through controlled inhibition processes, and we explain the positive priming obtained in the older adults group through automatic recuperation processes.