The spatial coding of responses can depend on the spatial features of action goals

In this work, we aimed to explore whether the spatial coding of responses is influenced by the spatial features of the action goal and whether this coding extends beyond the spatial features of the response keys to include the spatial features of the tools used. Therefore, we employed a size-based Simon effect in which participants were presented with either a large or small object, appearing in blue or orange, during each trial. Depending on the color, participants had to press a switch using a stick with either a large or small component. This component was located at either the end of the stick (Experiment 1) or in the middle (Experiment 2). In Experiment 3, the size difference between the stick components was larger than in Experiment 1. Importantly, the size of both possible keys was strictly similar. Our findings revealed a consistent pattern across all three experiments. Participants exhibited shorter response times when the size of the stimulus matched the size of the stick component compared to when it did not. These findings suggest that participants code their responses based on the spatial features of the action goal (i.e., size) and that this coding extends beyond the response keys to include features of the tools used. These results contribute to our understanding of action representation and provide insights into the neurocognitive processes associated with tool use.