Telling things apart: the distance between response keys influences categorization times.

People use spatial distance to talk and think about differences between concepts, and it has been argued that using space to think about different categories provides a scaffold for the categorization process. In the current study, we investigated the possibility that the distance between response keys can influence categorization times in binary classification tasks. In line with the hypothesis that distance between response keys can facilitate response selection in a key-press version of the Stroop task, our results showed that responses on incongruent Stroop trials were significantly facilitated when participants performed the Stroop task with response keys located far apart, compared with when they performed the task with response keys located close together. These results support the idea that the spatial structuring of response options facilitates categorizations that require cognitive effort, and that people can incorporate environmental structures such as spatial distance in their thought processes. Keeping your hands apart might actually help to keep things apart in your mind.