Sunday, August 13, 2006

Complex Choices Better Made Unconsciously? A critical exchange...

I thought it worth reproducing a current exchange in Science Magazine:

In their Report "On making the right choice: The deliberation-without-attention effect" (17 Feb., p. 1005), A. Dijksterhuis and colleagues reported the intriguing finding that when participants had to choose among four cars on the basis of various attributes, a period of conscious reflection worsened performance. They took this as evidence that complex choices are better when made unconsciously. A close examination of their methods, however, suggests a less startling interpretation.

Because of the easily confusable statements about the four cars, the 4-min period of reflection would cause considerable memory interference and leave participants utterly confused (was it the Hatsdun that had good handling and the Kaiwa no cupholders, or the other way round?). Memory research in the Bartlettian tradition has revealed many examples of such self-generated interference (1). The unconscious group made their decision after a similar 4-min period filled with a distractor task. Knowing that they would have no further opportunity for reflection prior to being required to make their choice, these individuals probably just made their decision at the end of the study period based on their overall impression of which car was best. This alternative account makes a simple and testable prediction, namely, that memory recall will be worse in the conscious condition.

An interesting but unnoted aspect of the findings was that the deliberation group chose the best car on only about 25% of occasions, exactly at chance. Does conscious deliberation yield no more than random results? The alternative account suggested here offers an explanation: It must have been because these individuals were faced with an insurmountable memory challenge and were completely confused about which attributes went with which car.

In any event, the decision problem presented in this study is very unlike the way we normally deliberate about a problem. When choosing between cars, we don't expend effort struggling to recall their attributes; we familiarize ourselves with the relevant attributes during the information search stage, and if we can't recall some attribute, we find it out. Dijksterhuis et al.'s findings would be altogether more compelling if they were replicated in a situation in which the 4-min deliberation period was spent studying the cars' attributes. But the likelihood is that under such circumstances, the best alternative would be selected by close to 100% of participants.

Reference 1. H. L. Roediger, E. T. Bergman, M. L. Meade, in Bartlett, Cognition and Culture, A. Saito, Ed. (Routledge, London, 2000), pp. 115-134.

David R. Shanks
Department of Psychology
University College London
Gower Street
London WC1E 6BT, UK

In our work on the "Deliberation-without-attention" effect, we found that, under complex decision circumstances, unconscious thinkers made better decisions than conscious deliberators. Conscious deliberators suffer from the low memory capacity of consciousness, which renders it impossible for them to take into account substantial amounts of information simultaneously. Unconscious thinkers, on the other hand, are not negatively affected by such capacity constraints. Shanks offers alternative explanations for our findings for both conscious deliberators and unconscious thinkers.

Shanks argues that our conscious thinkers may have faced memory problems. However, memory problems are not causing the effects we see. We have shown that even when the statements are presented in blocks (i.e., first all information on car A, then on car B, etc.), conscious deliberation still produces poor results (1). In addition, we have shown that even when people do have all the information at hand during conscious deliberation, it still produces poor results (2).

Shanks's suggestion that unconscious thinkers simply stick to the initial decision they made immediately after processing the information is not correct. In other experiments (1-3), we have compared unconscious thinkers with people who made decisions immediately after having received all the information, and unconscious thinkers performed better. Unconscious thought does lead to changes in preference, and it does so for the better.

Shanks also notes that under complex conditions, decisions made by conscious deliberators are no better than chance. Although conscious deliberation itself cannot be said to be random, the decisions produced by conscious deliberation are under some circumstances not superior to randomly generated decisions. There are moderators at work here, of course (e.g., expertise). Thus, the idea that conscious deliberation before making decisions is always good is simply one of those illusions consciousness creates for us.

Finally, Shanks observed that our experiments do not reflect the way people normally make decisions. This is true, as is usually the case with lab experiments. However, that is exactly the reason we included two field studies in our Report. In the field studies, people made real decisions with real consequences. These studies also confirmed the "deliberation-without-attention" hypothesis.

References 1. A. Dijksterhuis, J. Pers. Soc. Psychol. 87, 586 (2004). 2. A. Dijksterhuis, Z. van Olden, J. Exp. Soc. Psychol., in press. 3. A. Dijksterhuis, L. F. Nordgren, Pers. Psychol. Sci. 1, 95 (2006).

Ap Dijksterhuis
Maarten W. Bos
Loran F. Nordgren
Rick B. van Baaren
Department of Psychology
University of Amsterdam
Roetersstraat 15, 1018 WB
Amsterdam, the Netherlands

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