Late at night, in a basement laboratory at Stanford University, Brian Knutson made a startling discovery: our brains lust after money with the same neurons that they crave sex.
It was May 2004 and Knutson, a professor of neuroscience and psychology at the Californian university, was sending student volunteers through a high-power imaging machine called an fMRI.
Deep inside each subject's head, electrical currents danced through a bundle of neurons about the size and shape of a peanut. Blood was rushing to the brain's pleasure centre as students executed mock stock-and-bond trades. On Knutson's screen, this region of the brain, the core of human desire, flashed canary yellow.
Knutson, 38, concluded that the pleasure of orgasm, the high from cocaine, the rush of buying Google at US$450 a share - the same neural network governs all three. What's more, our primal pleasure circuits can, and often do, override our seat of reason, the brain's frontal cortex, the professor says. In other words, stocks, like sex, sometimes drive us crazy.