The present study investigated the effects of seven principles drawn from cognitive models of ethnic prejudice, general information processing models and persuasion models, on levels of ethnic prejudice. It was hypothesized that exposure to cue cards incorporating these principles would result in lower levels of prejudice than cue cards which did not incorporate the principles. A total of 400 caucasian participants were randomly assigned to experimental conditions (where participants were exposed to a cue card incorporating or omitting each of the seven principles), or the control condition (with no cue card exposure), and completed a questionnaire measuring ethnic prejudice. Results revealed that the absence of the principles in the cards led in several cases to unwanted negative effects (higher levels of prejudice than the control group). Reasons for these findings and implications for launching poster campaigns to reduce ethnic prejudice are discussed.