Things can be told apart: no influence of response categories and labels on the distance effect in Stroop tasks

A recent finding suggests that people use spatial distances of responses to separate nonspatial information in a simple categorization task like the Stroop task. It was suggested that the larger the distance becomes the easier the categorization will get; indeed, with large distances between response keys a smaller Stroop effect was observed by Lakens and colleagues (2011) as compared with small distances. This is a noteworthy finding albeit the published experiments suffer from two confounds which open the door for explanations of the distance effects in terms of spatial mismatch and recoding strategies. We conceptually replicated the results previously observed without these confounds and confirm the main result of Lakens et al. (2011) in that Stroop effects were significantly smaller if the distance between the response keys increased.