The claim
The theory, proposed by Ap Dijksterhuis and colleagues, argues that conscious thought handles only a few pieces of information at a time, while unconscious processing can weigh many attributes. On this view, sleeping on a complicated decision is more than rest: thinking continues outside awareness.
The typical experiment
Participants read many facts about options, such as cars or apartments. Some choose at once, some deliberate, and some are distracted by another task before choosing. Early studies reported that distracted participants picked the objectively better option more often.
Why the evidence is contested
Later work has been far less supportive. A large replication and meta-analysis found little reliable advantage for unconscious thought. Critics suggest that any apparent benefit may reflect impressions formed while reading the information, or the unfair conditions under which deliberators were asked to think. The idea that distraction improves choice remains unproven, though few researchers dispute that much mental processing happens outside awareness.
Further reading
- Dijksterhuis, A., & Nordgren, L. F. (2006). A theory of unconscious thought. Perspectives on Psychological Science, 1, 95-109.
- Nieuwenstein, M. R., Wierenga, T., Morey, R. D., Wicherts, J. M., Blom, T. N., Wagenmakers, E.-J., & van Rijn, H. (2015). On making the right choice: A meta-analysis and large-scale replication attempt of the unconscious thought advantage. Judgment and Decision Making, 10, 1-17.