The aim of this study is to demonstrate how the execution of particular task-specific motor movements can influence subjects’ ratings of simple stimuli. Sixty-four participants in one control and two experimental groups rated lines of 36 different lengths. Lines appeared on a computer screen and subjects gave their ratings using a standard keyboard. In the experimental groups trials did not change automatically, but subjects had to press a specific button (called the “trial change button”), which was next to one of the response buttons. It was hypothesized that this manipulation would lead to assimilation of the ratings toward the category whose button was next to the trial change button. The results confirmed this hypothesis. Possible explanations of the results are discussed.