Choice Blindness: The Incongruence of Intention, Action and Introspection

Abstract: This thesis is an empirical and theoretical exploration of the surprising finding that people often may fail to notice dramatic mismatches between what they want and what they get, a phenomenon my collaborators and I have named choice blindness. The thesis consists of four co-authored papers, dealing with different aspects of the phenomenon. Paper one presents an initial set of studies using a computerised choice procedure, and discusses the relation of choice blindness to the parent phenomenon of change blindness. Paper two is the most central paper of the thesis. In this study, participants were shown pairs of pictures of female faces, and were instructed to choose which face in each pair they found most attractive. In addition, on some trials, immediately after their choice, they were asked to verbally describe the reasons for choosing the way they did. Unknown to the participants, on certain trials, a double-card ploy was used to covertly exchange one face for the other. On these trials, the outcome of the choice became the opposite of what they intended. Counting across all conditions of the experiment no more than a fourth of all such manipulated trials were detected. But not only were the participants in the experiment blind to the manipulation of their choices, they also offered introspectively derived reasons for preferring the alternative they were given instead. A second major conclusion of this paper is that normal participants may produce confabulatory reports when asked to describe the reasons behind their choices. Paper three applies this form of analysis of introspection and confabulation to a second corpus of reports collected within the choice blindness paradigm. In this paper we use word-frequency and latent semantic analysis (LSA) to contrast the introspective reasons given in non-manipulated and manipulated trials, but very few differences between these two groups of reports were found. In paper four, passer-by shoppers in a local supermarket were invited to sample two different varieties of jam and tea, and to decide which alternative in each pair they preferred the most. After their choice, the participants were asked to again sample to chosen alternative and describe why that one was preferred. At this point, the content of the sample containers were secretly switched, so that the outcome of the choice became the opposite of what the participants intended. No more than a third of the manipulated trials were detected, thus demonstrating considerable levels of choice blindness for the taste and smell of two different consumer goods.