Are complex decisions better left to the unconscious? Further failed replications of the deliberation-without-attention effect

The deliberation-without-attention effect occurs when better decisions are made when people experience a period of distraction before a decision than when they make decisions immediately or when they spend time reflecting on the alternatives. This effect has been explained (e.g., Dijksterhuis, 2004) by the claim that people engage in unconscious deliberation when distracted and that unconscious thought is better suited for complex decisions than conscious thought. Experiments 1, 2A, and 2B in this study included a dominant alternative and failed to find evidence for this effect. Experiment 3 removed the dominant alternative and manipulated mode of thought within-subjects to eliminate alternative explanations for the failed replication. In all experiments participants did not make better decisions after unconscious thought; decisions were consistently better than chance when made immediately after the encoding of information. Encouraging people not to think about complex decisions appears to be unwarranted.