( Gerd Gigerenzer -Max Planck Institute for Human Development - Psychological Review © 2017 American Psychological Association 2017, Vol. 124, No. 2, 179–196) Ignorance is generally pictured as an unwanted state of mind, and the act of willful ignorance may raise eyebrows. Yet people do not always want to know, demonstrating a lack of curiosity at odds with theories postulating a general need for certainty, ambiguity aversion, or the Bayesian principle of total evidence.