Amending limb movements to mechanical perturbations under choice reaction time conditions

This paper examines the amendment of limb movements to mechanical perturbations under choice reaction time conditions. The two experiments reported were designed to examine the question of whether amendment latencies increase under choice conditions using two different choice manipulations. In Experiment 1, choice was manipulated by varying the duration of a mechanical perturbation in a known direction, while in Experiment 2 the strategy was to present perturbations of similar duration but unknown direction. Subjects produced discrete timing responses (700 ms-70 degrees) during which perturbations were interjected on random trials. The results reported reflect the outcome accuracy, the kinematics of the responses and latency of response modifications as a function of the various choice manipulations. The data demonstrated no statistically significant increases in reaction time as a function of choice manipulations. Although latencies did not significantly vary, both experiments demonstrated a significant decrease in response accuracy for the choice conditions. Collectively, the results are discussed in relation to the discrepancies between previous proprioceptive choice reaction time studies, which appear to stem from inconsistencies in both experimental methods and data analysis procedures.