How dopamine enhances an optimism bias in humans

Curr Biol. 2012 Aug 21;22(16):1477-81. doi: 10.1016/j.cub.2012.05.053. Epub 2012 Jul 12.


When predicting financial profits, relationship outcomes, longevity, or professional success, people habitually underestimate the likelihood of future negative events. This well-known bias, termed unrealistic optimism, is observed across age, culture, and species, and has a significant societal impact on domains ranging from financial markets to health and well being. However, it is unknown how neuromodulatory systems impact on the generation of optimistically biased beliefs. This question assumes great importance in light of evidence that common neuropsychiatric disorders, such as depression, are characterized by pessimism. Here, we show that administration of a drug that enhances dopaminergic function (dihydroxy-L-phenylalanine; L-DOPA) increases an optimism bias. This effect is due to L-DOPA impairing the ability to update belief in response to undesirable information about the future. These findings provide the first evidence that the neuromodulator dopamine impacts on belief formation by reducing negative expectations regarding the future.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Affect / drug effects*
  • Attitude*
  • Citalopram
  • Dopamine Agents / pharmacology*
  • Dopamine*
  • Female
  • Humans
  • Levodopa / pharmacology*
  • Male
  • Serotonin Uptake Inhibitors
  • Young Adult


  • Dopamine Agents
  • Serotonin Uptake Inhibitors
  • Citalopram
  • Levodopa
  • Dopamine