Investigating Grounded Conceptualization: Stimulus-Response Compatibility for Tool Handles Is Due to Spatial Attention

Brain imaging research shows that viewing tools activates regions of the cortex implicated in performing actions with that tool. Grounded (or embodied) theories of cognition propose that this activity reflects the activation of motor representations that are constitutive of the object concept. Behaviorally, participants respond faster with the hand that is aligned with the handle of an object. This stimulus-response compatibility (SRC) effect is often taken as evidence supporting the hypothesis that motor representations are activated in response to the visual presentation of tools during conceptual processing. To test this hypothesis, we trained participants to use a set of novel tools (manipulation group) or to report spatial information about the tools (spatial group) in preparation for a Martian archeological dig. We investigated compatibility effects in a conceptual judgment task and a visual discrimination task. Compatibility effects were observed for both groups regardless of experience. These effects were predicted by the salient parts of objects specified by task demands and not by motor experience with the objects. This result provides evidence that compatibility effects with tools reflect a general stimulus-response compatibly effect due to visual attention.