- Evaluative conditioning (EC) is a change in the evaluation of a stimulus after the stimulus co-occurred with affective stimuli. The present research examined whether EC of one stimulus depends also on the co-occurrence of another stimulus with positive or negative stimuli. We paired two target people with affective stimuli. We found that a person who appeared eight times with positive stimuli and eight times with negative stimuli was liked more when the other person appeared always (16 times) with negative stimuli than when the other person appeared always with positive stimuli. The manipulation did not change the US evaluation or the general standard on the value dimension of what a positive or negative stimulus is. We suggest that like other evaluative traits (e.g., evil, pretty) co-occurrence with affective stimuli is sensitive to temporary standards. The manipulation changed the standard of what co-occurrence with affective stimuli is considered positive versus negative.