At arm's length: competing and complementary mechanisms

Abstract

Three experiments utilised video stimuli, showing an agent presenting objects in a behavioural stimulus-response compatibility paradigm, implicitly measuring responses to the agent’s wrist orientation and hand of presentation. A vertical wrist orientation might cue a complementary action response in an ecological setting, thus testing spatial congruence against interactive and imitative responses. In experiment 1, there was a significant main effect of the actor’s arm, (p<.001), responses to the actor’s right arm being faster than to the left arm. There were two significant interactions in experiments 2 and 3, between the actor’s arm and the participants’ hand of response, (p<.001 and p=.05, respectively). Contrary to experiment 1, these interactions are akin to a spatial Simon effect. Possible interpretations of these results are discussed in terms of visual occlusion, kinematics, and affordances, all of which are aspects of spatial negotiation.