Superstitious perception: Response-independent reinforcement and punishment as determinants of recurring eccentric interpretations Robert C. Mellon * Division of Clinical Psychology, Department of Psychology, Panteion University of Social and Political Sciences,136 Syngrou Avenue, 17671 Athens, Greece article info Article history: Received 2 January 2009 Received in revised form 9 June 2009 Accepted 30 June 2009 Keywords: Superstition Perception Response-independent reinforcement Response-independent punishment Obsession, dysfunctional cognition abstract This study provided controlled observations of a potential mechanism for the determination of the repetitive, aberrant perceptions or interpretations of everyday events that figure prominently in a range of psychological disorders: the adventitious reinforcement of acts of cognition by the actual conse- quences of concurrent motor acts. Adults made a series of two-choice brightness discriminations; on 60% of trials, choosing the brighter stimulus produced a ‘‘correct’’ signal while errors produced an aversive sound. On 40% of trials, the choice stimuli did not in fact differ in brightness; the consequences of responding on these ‘‘identical stimuli’’ trials differed across blocks of trials. Thus, on these trials perceptual judgments were directly followed by events that they did not produce. When all choices on identical stimuli trials were punished with the ‘‘error’’ sound, subjects showed little preference for the left-side or right-side identical stimuli, but when all choices of identical stimuli were reinforced with the ‘‘correct’’ light, individual preferences for the left-side or the right-side stimuli substantially increased. As the consequences of responding on identical stimuli trials were independent of the stimuli chosen, these findings provide evidence for superstitious perception, the reinforcement of perceptual acts by events that do not depend upon their occurrence. Ó 2009 Elsevier Ltd. All rights reserved. The behavior of persons who satisfy the diagnostic criteria for a variety of psychological disorders is characterized by recurring idiosyncratic perceptions or interpretations of everyday objects and events. Paranoia is perhaps the most obvious example, but in the anxiety disorders a person’s frequent perceptions of threat are judged by others to be disproportionate to reality, whereas mood disorders, narcissistic personality disorder, and eating disorders (among others) are characterized by repetitive unrealistic self- appraisal. The relation of such behaviors to antecedent and consequent conditions is often difficult to specify; in consequence, they are often attributed to an underlying pathology that is unob- served independent of the behaviors that it is said to cause. The present report provides experimental evidence for the existence of a behavioral process that might contribute to the development and maintenance of unconventional, stereotypic perceptions of everyday circumstances: their adventitious strengthening by events that repeatedly follow upon their emission, but are not produced by them. In the behavior analytic approach, the process in which the consequences of cognitive or motor acts increase the frequency of occurrence of similar acts is called reinforcement. When behavior is reinforced by an event that it produces, the process is called positive reinforcement and the event a positive reinforcer, whereas when behavior is reinforced by the termination of an event, the process is called negative reinforcement and the event a negative reinforcer. But behavior might be positively or negatively reinforced by events that succeed it, even when the behavior does not bring them about. The positive or negative reinforcement of behavior by events that do not depend upon its occurrence is called adventitious or response-independent reinforcement. Behavior might also be adventitiously punished, as when a negative reinforcer follows upon the emission of an act that did not produce it. For a hypothetical example of the adventitious reinforcement and punishment of interpretations or perceptions, imagine a man who is experiencing great discomfort on a blind dinner date. During a particularly awkward lull in conversation, he finds himself grip- ping the arms of his chair, and suddenly discerns that this surface might have been contaminated by a previous patron. He excuses himself and retires to the men’s room, where he washes his hands at length. Despite his concern for his own health, he immediately feels relief from the termination of contact with his date. It was his movement towards the men’s room that freed him from an uncomfortable social situation, eliciting relief, but the termination of aversive stimulation followed upon his perception that his hands * Tel./fax: þ30 210 920 1723. E-mail address: mellon@panteion.gr Contents lists available at ScienceDirect Behaviour Research and Therapy journal homepage: www.elsevier.com/locate/brat 0005-7967/$ – see front matter Ó 2009 Elsevier Ltd. All rights reserved. doi:10.1016/j.brat.2009.06.016 Behaviour Research and Therapy 47 (2009) 868–875