Visual discrimination and response programming

Summary Choice reaction time (RT) depends on the relationship between responses, and these dependencies are usually interpreted in terms of the advance-specification assumption. According to this assumption characteristics that are the same for the choice responses can be specified in advance of the response signal, thus allowing faster RTs. Since the advance-specification assumption is called into question by some of the available data, an alternative interpretation is suggested and formalized in terms of an accumulator model. According to the programming-interactions assumption, stimulus processing is tightly linked to response programming, so that both the possible responses are programmed as long as there is uncertainty with regard to stimulus identity. This gives rise to interactions between simultaneous processes of motor programming. Predictions of this assumption for the joint effects of signal similarity and the relationship between responses are tested and confirmed.This research was supported by grant no. He 1187/3–1 from the Deutsche Forschungsgemeinschaft