The pleasure of "maybe": both tease and terrorist exert control by fostering uncertainty in their targets

But in a series of studies in the mid-1990s, Wolfram Schultz, a neuroscientist then at the University of Fribourg in Switzerland, did some critical studies that threw that simple picture into disarray. Schultz trained monkeys to perform simple tasks to gain a reward. For example, if an animal pressed the correct lever, after a few seconds' delay it would get a bit of some desirable food. There was one special condition: a light would come on, signaling to the monkey that it could now begin its task. One might predict that the dopaminergic pathway would be activated after that food reward was received. But that's not what happened. The activity peaked right after the light came on, before the monkey performed its task.

In this context, the pleasurable dopamine isn't about reward. It's about anticipating the reward. It's about mastery and expectation and confidence. ("I know what that light means; I know the rules: if I press the lever, then I'm going to get some food. Hey, I'm all over this. This is going to be great.")

Psychologists refer to the period of anticipation, of expectation, of working for reward as the "appetitive" stage; the stage afterward, which commences with reward, they call the consummatory stage. Schultz's findings show that if you know your appetites are eventually going to be sated, pleasure is more about the appetite than about the sating. I am reminded of the cynical observation of a classmate in college, a person with a long string of disastrous relationships. "A relationship," he used to say, "is the price you pay for the anticipation of it."

Well, how about that? We've just sorted out the neurochemistry of putting up with thirty-year mortgages. All you need to do is train for longer and longer intervals between light and reward, and those anticipatory bursts of dopamine will fuel increasing amounts of lever pressing, or monthly payments.

One of the two recent studies I alluded to earlier fills in a critical gap in this story. Writing in the 10 April 2003 issue of Nature, Paul E. M. Phillips and his colleagues from the University of North Carolina, Chapel Hill, tell how they have measured bursts of dopamine in rats down to the millisecond. They have shown that the burst comes just before the behavior. And here's the clincher: when they artificially stimulated the dopamine, release (rather than letting the light cue trigger it), the rat suddenly started pressing the lever. The dopamine fuels the behavior.

How might these findings apply to the savanna soap opera of Jonathan and Rebecca? There he sits, dozing in the equatorial sun. Rebecca appears in the distance (dramatic entrance at the other end of the field, wind-swept fur, the whole deal). Jonathan's appetitive light goes on, and his ventral tegmentum gets all hyperactive and releases dopamine like mad. This gives his frontal cortex the impetus to do the harder thing, to resist the easy out of just sitting there in his midday torpor. Instead, he gets up and walks across that endless field, powered by the anticipatory certainty (Wagner now in the background) that she is going to let him groom her.