Recent research in cognitive science has demonstrated that when people vividly imagine or visualize personal childhood events, their subjective con®dence increases in the probability that these visualized incidents actually occurred. This study seeks not only to replicate what has been called the imagination in¯ation eect in a sample of undergraduates and middleaged factory workers but also to identify individual dierence variables that could predict susceptibility to suggestibility. Drawing from Rotter's (1982) social learning theory and Benjamin's (1974) structural analysis of social behaviour (SASB) model for interpersonal behaviour, the two experiments reported test the extent to which locus of control for reinforcement, dissociability, and a hostile/self-controlling introject (self-concept) could predict the imagination in¯ation eect. Results indicate that: imagination in¯ation is a robust and replicable phenomenon with young adults, but did not occur in a non-college population; with undergraduates, both external locus of control and dissociability correlate in a positive, signi®cant, and predicted way with suggestibility; introject variables correlate signi®cantly with imagination in¯ation, but not in the predicted manner. Findings are discussed in terms of helping psychologists better understand potential iatrogenic processes in psychotherapy.

Recent research in cognitive science has demonstrated that when people vividly imagine or visualize personal childhood events, their subjective confidence increases in the probability that these visualized incidents actually occurred. This study seeks not only to replicate what has been called the imagination inflation effect in a sample of undergraduates and middle‐aged factory workers but also to identify individual difference variables that could predict susceptibility to suggestibility. Drawing from Rotter's (1982) social learning theory and Benjamin's (1974) structural analysis of social behaviour (SASB) model for interpersonal behaviour, the two experiments reported test the extent to which locus of control for reinforcement, dissociability, and a hostile/self‐controlling introject (self‐concept) could predict the imagination inflation effect. Results indicate that: imagination inflation is a robust and replicable phenomenon with young adults, but did not occur in a non‐college population; with undergraduates, both external locus of control and dissociability correlate in a positive, significant, and predicted way with suggestibility; introject variables correlate significantly with imagination inflation, but not in the predicted manner. Findings are discussed in terms of helping psychologists better understand potential iatrogenic processes in psychotherapy. Copyright © 1998 John Wiley & Sons, Ltd.