Biases and fallacies, memories and predictions: comment on Roy, Christenfeld, and McKenzie (2005)

Comparative theory testing is a useful method for assessing the value of a new theoretical account such as the memory bias account of optimistic time predictions. However, such comparisons can be misleading when they do not carefully consider the domain limitations of the respective theories. M. M. Roy, N. J. S. Christenfeld, and C. R. M. McKenzie have contrasted the memory bias and planning fallacy accounts in their ability to explain the prevalence and degree of optimistic bias in time predictions. However, the authors argue that many of the points of distinction they draw are actually reflections of the domain limitations of the 2 theories. The authors clarify the definition and scope of the planning fallacy account and show how the apparent contradictions diminish or disappear.