grantor:
University of TorontoRepetition of advertising claims increases belief in those claims, this phenomenon, called the 'truth effect', is mediated by consumers' memory for the claims. Since memory is not a unitary phenomenon, memory for the item (i.e. the advertising claim) and memory for the source of the item (i.e. where the claim was encountered) may have a differential impact on the truth effect. This may be of particular importance as older adults often show memory deficits compared to younger adults, and may even be particularly poor in remembering source information. Fortunately, it is possible to minimize these memory deficits through cognitive support. Therefore, the questions addressed in this dissertation are: Do declines in memory make the elderly more vulnerable to the truth effect? Are there conditions under which age-related differences in the truth effect can be abolished? Experiment 1 assessed the level of memory impairment in the elderly as compared to the young, and its influence on the truth effect. The elderly were mom susceptible to the truth effect and this effect was mediated via their higher false-alarm rates and poorer source memory. Experiment 2 demonstrated that if one used imagery instructions at encoding, a form of cognitive support that ameliorates elderly item memory and source memory deficits, then the truth effect differences between the young and the elderly disappear. Taken together, these experiments showed that the elderly are more susceptible to truth effect due to poorer memory, and if their memory is enhanced using cognitive support, their susceptibilty to the truth effect can be overcome. Experiment 3 was designed to investigate the impact of source credibility on the truth rating of an item. While earlier research had suggested that source credibility influences truth ratings, it was not clear when the credible source exerts its influence--is it when one is exposed to an advertising claim (at encoding), or, when it is subsequently remembered (at retrieval), or, at both times? Experiment 3 showed that while the credibility of source at encoding as well as the source remembered at retrieval influenced truth ratings of a claim, the source at retrieval influenced truth ratings the most.Ph.D
