Philip Zimbardo is fascinated by why people can behave in awful ways. Some psychologists believe those who commit cruelty are innately evil. Zimbardo disagrees.

The work of memory researchers Alan Baddeley and Graham Hitch is a prime example of the ways in which good critical thinkers approach questions and the problems they raise. In the 1960s, researchers into human memory began to understand memory as comprising not one, but two systems. The first was a short-term system handling information for mere seconds. The second was a long-term system capable of managing information indefinitely. They also discovered, however, that short-term memory was not simply a 'filing cabinet,' as many had thought, but was actively working on cognitive - or...