UC Berkeley

The hindsight bias may not be as robust as previously believed. Also known as the “knew-it-all-along effect” (Fischhoff, 1975) the hindsight bias refers to the inability for individuals to remember their previous state of knowledge after learning an outcome. Researchers have found people fall victim to hindsight biases in a variety of domains, including general knowledge (Fischoff, 1977; Wood, 1978), medical decisions (Arkes, Wortmann, Saville, & Harkness, 1981), and political outcomes (Fischhoff & Beyth, 1975). Multiple failures to debias, with methods including informing participants about the bias (Fischhoff, 1977) and manipulating participant perspective (Wood, 1978) further grew the reputation for the strength of this bias. However, we must interpret older results in the behavioral sciences with new perspective on the importance of sample size and statistical power (Ioannidis, 2005). This dissertation proposes to investigate when and why hindsight bias fails to appear, and what it means for the psychological processes underlying the hindsight bias, and more broadly, the interpretation of older psychological research.