Age differences in conjunction fallacies and information-processing styles

by Ma, Xiaodong.

Yiwei Chen, Advisor Probability reasoning plays an essential role in our everyday life. It has been argued that making decisions under uncertain circumstances were becoming more and more important with aging. The current study examined if there were age differences in conjunction fallacies and in the intuitive-experiential and analytical-rational information processing styles based on the Cognitive-Experiential Self-Theory (CEST). In experiment 1, 26 undergraduate students (14 female) and 26 older adults (18 female) completed a lottery problem first and then the Linda problem. The cognitive measures were administrated at the last. Results revealed that for both age groups, the conjunction error (CE) rates were significantly reduced in response to the Linda problem, following the lottery problem. However, no age differences were discovered regarding CEs for either the Linda problem or the lottery problem. Furthermore, an age by gender interaction effect was found for both rational and experiential scales. Results were discussed in terms of the possibility of gender differences in Rational-Experiential information processing styles masking the expected age effects. Experiment 2 investigated the robust resistance to the correct solution of the Linda problem. Fifty-two younger adults attended study 2, and they were randomly assigned to two groups with each group have 26 participants. Group 1 finished the lottery problem first, and then the Linda problem. Group 2 completed the lottery problem, then the revised Linda problem, which provided base rates for the two events (i.e., Linda is a iii bank teller and Linda is active in the feminist movement). Results showed that the CE rates of the Linda problem of group 2 were significantly reduced comparing with those of group 1. The findings provided supporting evidence for the concrete-unnaturalness explanation and also provided deeper understanding for the high rate of CEs in the Linda problem. iv This thesis is dedicated to my family, my teachers, and my friends, who always had a faith in me, raised me up, and supported all of my work. v