Carry-over effects can modulate emotional Stroop effects

The emotional Stroop task has been widely used to examine attentional bias in a variety of psychological disorders. In one format of this task, words are presented to participants in a mixed randomised or quasi-randomised sequence. We present data from two independent studies involving smokers, the results of which show that words appearing after smoking-related items in the mixed sequence are responded to more slowly than words appearing after neutral items. These carry-over effects may reduce the size of emotional Stroop effects on the mixed Stroop task. We discuss the implications of these carry-over effects for research using the emotional Stroop task.