The relation between response-specificity, S-R compatibility, foreperiod duration and muscle-tension in a target aiming task

Three experiments are reported aiming at a further understanding of the effect of response-specificity, operationalized as the degree of commonality of direction of movements. In a previous study, Spijkers (1987) has claimed that response-specificity affects the readiness of the motor system and is not related to response-selection processes. These suppositions were generally confirmed in experiments 1 and 2 respectively. Common to both experiments were the variables average movement velocity and response-specificity. In experiment 1 the effect of the additional variable foreperiod duration was found to interact with that of response-specificity, hereby confirming its expected relation to the muscular system. The effect of response-specificity did not interact with that of spatial S-R compatibility in the second experiment, but also failed to show a main effect. The third experiment examined the supposed relation of response-specificity more directly through manipulation of the muscle-tension of the responding limb. The predicted form of the interaction between the effect of response-specificity and muscle-tension was confirmed which provided additional evidence for the interpretation of response-specificity effects in terms of differential muscular activation.