Publication Date


Degree Program

Department of Psychology

Degree Type

Master of Arts


It is sometimes necessary to make validity judgments about information with which we are unfamiliar, because we have no factual knowledge about the event. Under these circumstances, subjective evidence, such as whether the statement has been seen or heard in the past, may be used to judge validity. Previous research has shown that the repetition of unfamiliar, but plausible statements increases the judged validity of the statements. In other words, the more one hears a particular statement, the more one believes it to be true. The present study has been designed to explore this "truth effect." The first experiment examined the influence of increasing age on the truth effect and recognition of repeated statements. Younger and older adults were asked to rate a series of statements for validity. Two weeks later, the subjects rated a similar list containing some new statements along with statements repeated from the first session. Subjects were also given a task to assess their recognition of repeated statements. The results indicated that older adults demonstrated the truth effect to a greater extent than younger adults, despite the fact that their recognition scores were much less accurate. These results indicate that repetition and recognition have independent influences on perceived validity. A second experiment was conducted to examine the effect of feedback on the truth effect and recognition judgments. It was proposed that ratings for repeated items in the second session would increase in judged validity due to the unintentional influence of familiarity. If feedback information was deliberately recollected, this misattribution of familiarity to credibility could be checked for false statements. Subjects were asked to rate statements for validity, and feedback as to the actual truth value of some of the items was given in the first session. Subjects rated repeated and new items in the second session for validity, as well as performing a source recognition task. The results of the second experiment showed that, again, both young and older adults demonstrate the truth effect. For young subjects, true statements were rated the truest, followed by non-feedback, nonrepeated, and false statements. The same pattern was found for older subjects, except that the false and non-repeated statements were rated similarly. As in the first experiment, older subjects were less accurate than young subjects at recognizing the source of repeated statements. Again, repetition and recognition were found to influence the truth effect independently. The results of this study indicate that the effects of repetition may influence older adults more than young adults, due to their less efficient memory for source. This deficit in source memory would serve to make older individuals less skeptical about the credibility of their knowledge, and thus more susceptible to false beliefs.


Cognition and Perception | Psychology