“As he throws himself into one scheme after another, he draws lessons that improve his focus and judgment. He knits what he learns into mental models of investing, which he then uses to size up more complex opportunities and find his way through the weeds, plucking the telling details from masses of irrelevant information to reach the payoff at the end. These behaviors are what psychologists call “rule learning” and “structure building.” People who as a matter of habit extract underlying principles or rules from new experiences are more successful learners than those who take their experiences at face value, failing to infer lessons that can be applied later in similar situations. Likewise, people who single out salient concepts from the less important information they encounter in new material and who link these key ideas into a mental structure are more successful learners than those who cannot separate wheat from chaff and understand how the wheat is made into flour.”