After a neutral stimulus co-occurs with an affective stimulus, the evaluation of the neutral stimulus shifts toward the valence of the affective stimulus. The present research tested what factors contribute to evaluation change when, while observing the co-occurrence, people also categorise the affective stimuli. In Experiment 1, categorisation by valence caused stronger change in the evaluation of the neutral stimulus than non-evaluative categorisation, but only when categorisation for each valence was consistently mapped to the same motor response. In Experiment 2, co-occurrence with extreme affective stimuli during the categorisation task caused stronger change in the evaluation of the neutral stimulus than co-occurrence with mild affective stimuli. These results suggest that when neutral stimuli co-occur with evaluative stimuli and with an evaluative categorisation response, both types of co-occurrence contribute to evaluative change. In Experiment 3, induced contingency awareness did not increase evaluative change. This might suggest that contingency awareness does not contribute to the effect.