Market Psychology Explained

Funny read from Paul Krugman written in the late 90's as the S&P500 was ca 20% higher: "But suppose that, for whatever reason, the market goes up month after month; your MBA-honed intellect may say "Gosh, those P/Es look pretty unreasonable", but your prehistoric programming is shrieking "Me want mammoth meat!" - and those instincts are hard to deny."