It's a Fact: Some People Never Learn

Any sysadmin could have told you this years ago. This is more of a case of science building up hard evidence to support common, albeit abstract, knowledge.

Some People Never Learn: "At first, the volunteers were shown sets of two symbols and were asked to select one. Each choice was followed by positive or negative feedback represented by a smiling or frowning face, respectively. The researchers then tested whether the men had learnt to choose the symbol that had the most positive feedback and avoid the one that led to the most negative feedback. The test showed that men carrying the A1 mutation responded less to negative feedback, implying that they were less successful at learning to avoid mistakes than the men in the other group."