We are strongly governed by hope and expectation: that we shall have pancakes for breakfast; that the handsome stranger across the room will smile at us; that our broker will quit sending out margin calls – you name it.
But, like the man said, hope deferred maketh the heart sick – so, just to keep our heart in good shape, hope must be transformed from time to time into the pleasure of fulfillment. For this purpose, we carry around in our skulls a complicated gadget known as the limbic or reward system, comprising several components for sorting out the different kinds of pleasure signals arriving from the outer world. The system also handles memory, learning and even decision-making, where your choice is the most pleasing of several options.
The principal components of the reward system have formidable Latin names, to discourage the laity: the amygdala, the cingulate gyrus, the hippocampus and thalamus and, most important of all, the nucleus accumbens, without which you would never laugh again. These devices are all buried deep in the brain, making it a sure bet they were all installed millions of years before hominids were even imagined. In fact, to be crude, it is hard to see how any species got its start without a similar gadget to encourage multiplication.
Curiously enough, then, considering its fundamental importance, no one knows the precise mechanism of pleasure, at least after the point where the nucleus accumbens gets its shot of dopamine. It will probably turn out to be nothing more exciting than the simultaneous discharge of a large number of forebrain neurons, graduated to cover the wide range of pleasures from a cool drink on a hot day to deep orgasm. But, in the words every future scientist is required to learn at his mother’s knee: “Further research is needed.”
One tends to think of pain as the other side of the pleasure coin, but, in fact, pain, which prompts flight rather than sticking around for more, has a quite different system – but not so different as to avoid occasional crossover, as when we weep for joy or laugh hysterically at devastating news. However, aside from these rare lapses, and like any complex system developed to the point of extinction, the reward system can sometimes go horribly wrong, as when we kill merely for the pleasure of it or indulge in psychopathic behavior, for examples of which I refer you to Dr. Kraft-Ebbing.
Complex systems are inherently vulnerable, so it is no surprise that humanity, which has found out how to tour the solar system, had no trouble short-circuiting the safety devices designed to protect us against unbearable pleasure or pain; a wide range of narcotics can give us a short-lived identification with the universe, though the terrible price to pay for abuse is an unendurable longing for a pleasure that can no longer be had.
So, if you like a good laugh now and again, be kind to your nucleus accumbens – it’s the only one you’ve got.