Response-response binding across effector-set switches.

A single encounter of a response together with a stimulus results in short-lived binding between the stimulus and the response. A repetition of any part of such a stimulus-response episode can then retrieve the whole episode, including the response. Recent findings have shown that similar binding is also possible between two successive but independently planned manual responses, indicating that binding processes also play a role in the coordination of action sequences. Action coordination in everyday life often includes alternation between different effector sets. Yet switching effectors has been shown to result in very clear partitioning of actions. Thus, it is unclear whether responses carried out via different effector sets (feet and hands) are as easily integrated as responses via a single effector set (hands). In two experiments, we investigated whether response-response integration is possible across effector-set switches, and compared the binding effects across effector sets to those within one effector set. In a prime-probe design, participants executed two responses at the prime and the probe-the first via their hands and the second via their feet (Exp. 1), or the first via either hands or feet and the second via hands (Exp. 2). The data from both experiments indicated binding between responses, even if the actions were carried out via different effector sets. However, bindings between responses that were carried out via different effector sets were weaker than bindings between responses via a single effector set. We concluded that binding constitutes a main function of action sequences in human behavior.