Gap effect and reaction time distribution: simple vs choice manual responses

Autor: W. Machado-Pinheiro, L.G. Gawryszewski, L.E. Ribeiro-do-Valle
Jazyk: angličtina
Rok vydání: 1998
Předmět:
Zdroj: Brazilian Journal of Medical and Biological Research, Vol 31, Iss 10, p 1313 (1998)
Druh dokumentu: article
ISSN: 0100-879X
1414-431X
DOI: 10.1590/S0100-879X1998001000012
Popis: It is well known that saccadic reaction times (SRT) are reduced when the target is preceded by the offset of the fixation point (FP) - the gap effect. Some authors have proposed that the FP offset also allows the saccadic system to generate a separate population of SRT, the express saccades. Nevertheless, there is no agreement as to whether the gap effect and express responses are also present for manual reaction times (MRT). We tested the gap effect and the MRT distribution in two different conditions, i.e., simple and choice MRT. In the choice MRT condition, subjects need to identify the side of the stimulus and to select the appropriate response, while in the simple MRT these stages are not necessary. We report that the gap effect was present in both conditions (22 ms for choice MRT condition; 15 ms for simple MRT condition), but, when analyzing the MRT distributions, we did not find any clear evidence for express manual responses. The main difference in MRT distribution between simple and choice conditions was a shift towards shorter values for simple MRT.
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