tools. “There’s a kind of sea change of belief in what you can and can’t explain,” he said. “People put people into scanners like this and do every manner of cognitive task, literally from having sex to thinking about the word sailboat. The experiments are working beautifully. I think the sky’s the limit.”6
A new scientific discipline to exploit these technological abilities seems to have emerged almost out of nowhere. The term neuroeconomics itself apparently first appeared in 2002.7 Before that, people like Montague had been referring to their studies as “neural economics.” In any event, the first attention-getting published paper in the new genre appeared in 1999, reporting a study by Paul Glimcher and Michael Platt of the Center for Neural Science at New York University. Glimcher and Platt had measured nerve-cell activity in the brains of monkeys performing a decision-making task. The results supported the notion that nervous activity reflects choice-making factors—that is, something like utility— that economists had already identified.
Monkeys, of course, are not obsessed with money, but they do really enjoy getting squirts of fruit juice and can be fairly easily trained to perform all sorts of tasks for a juice-squirt reward. In the Platt-Glimcher experiment, all a monkey was required to do was switch its gaze from a cross on a screen to one of two lights. Looking at a light earned a squirt of juice.
Looking at one of the lights, though, earned a bigger squirt than looking at the other. It didn’t take the monkey long to figure that out. (If I’m going to maximize my utility, the monkey obviously thought, I should look at the light on the right.) If the experimenters changed the high-reward squirt to the other light, the monkey caught on right away and preferred the new high-reward light.
None of that was very surprising—similar experiments had been done before. But in this case, Platt and Glimcher also recorded the activity of a nerve cell in a region of the monkey brain that processes visual input and is involved in directing eye movement. (If you must know, the cell was in the lateral intraparietal cortex, or LIP.)