Search and Learning

When people make decisions under uncertainty, they do not know what the consequences of their decisions will be or how likely those consequences are to occur. One solution for coping with this type of uncertainty is to actively explore the options, form an impression of the possible outcomes and their likelihoods, and then decide based on that information. An alternative solution we have recently begun exploring is to choose not to search for any information and instead to remain ignorant of what the future might hold.

Decisions from Experience

People can learn about the potential consequences of their decisions and the associated probabilities in two ways: by reading summaries of probability information or by personally experiencing the probabilistic consequences of their decisions, one at a time. Using simple monetary lotteries to compare these two choice types, we have observed a “description–experience gap,” a phenomenon by which rare events are given too much weight in decisions from description and too little weight in decisions from experience. This occurs partly because decisions from experience are based on small samples, where people are simply less likely to experience the rare event. The description–experience gap has been found to be robust across thousands of choices and to generalize beyond monetary gambles to domains including causal reasoning, consumer choice, investment decisions, medical decisions, and adolescent risk taking. 

Deliberate Ignorance

A more recent research avenue within our research group focuses on the decision to forgo search. Under some conditions, people choose to remain ignorant. For example, up to 55% of those who get tested for HIV do not return to pick up their results. We call the conscious choice not to seek or use information “deliberate ignorance”. What motivates individuals to do without information and what are the cognitive strategies underlying their choice?


  • Hertwig, R., & Erev, I. (2009). The description–experience gap in risky choice. Trends in Cognitive Sciences13, 517–523.
  • Hertwig, R., & Engel, C. (2016). Homo ignorans: Deliberately choosing not to know. Perspectives on Psychological Science11, 359–372. 
  • Hertwig, R., Wulff, D. U., & Mata, R. (2019). Three gaps and what they may mean for risk preference.Philosophical Transactions of the Royal Society B:Biological Sciences, 374: 20180140.
  • Wulff, D. U., Mergenthaler-Canseco, M., & Hertwig, R. (2018). A meta-analytic review of two modes of learning and the description–experience gap. Psychological Bulletin144, 140–176.
Go to Editor View