The neural basis of belief updating and rational decision making

Anja Achtziger, Carlos Alós-Ferrer, Sabine Hügelschäfer, Marco Steinhauser

Research output: Contribution to journalArticlepeer-review


Rational decision making under uncertainty requires forming beliefs that integrate prior and new information through Bayes rule. Human decision makers typically deviate from Bayesian updating by either overweighting the prior (conservatism) or overweighting new information (e.g. the representativeness heuristic). We investigated these deviations through measurements of electrocortical activity in the human brain during incentivized probability-updating tasks and found evidence of extremely early commitment to boundedly rational heuristics. Participants who overweight new information display a lower sensibility to conflict detection, captured by an event-related potential (the N2) observed around 260 ms after the presentation of new information. Conservative decision makers (who overweight prior probabilities) make up their mind before new information is presented, as indicated by the lateralized readiness potential in the brain. That is, they do not inhibit the processing of new information but rather immediately rely on the prior for making a decision.

Original languageEnglish (US)
Article numbernss099
Pages (from-to)55-62
Number of pages8
JournalSocial cognitive and affective neuroscience
Issue number1
StatePublished - Jan 2014


  • Bayesian updating
  • Conservatism
  • LRP
  • N2
  • Representativeness heuristic

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Cognitive Neuroscience


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