Dr. Johnson's main research interests are in the general areas of social cognition and intergroup processes. More specifically, he is interested in the structure of the self-concept, the role of the self and group identities in memory, prejudice reduction, stereotype formation and stereotype structure, and the effects of derogatory labels.

With his colleagues, Dr. Johnson has published a series of journal articles summarizing and examining the mechanism underlying illusory correlation in stereotyping effects. Other published work has examined the way people cognitively represent the self, their own groups, and other groups. The research has primarily been published in the British Journal of Social Psychology and Personality and Social Psychology Bulletin, and has been presented at the annual meetings of the American Psychological Association, Association for Psychological Science, Eastern Psychological Association, and the Society for Personality and Social Psychology.

His most recent work has examined the group-reference effect, stereotype subgroups, and terror management theory. Dr. Johnson also has an interest in consumer psychology, having co-authored a textbook on that topic.