The Science of Craving and Free Will

Why do we crave things that we do not need, or even worse, things that harm us?

As Aristotle once wrote: “It is of the nature of desire not to be satisfied, and most men live only for the gratification of it.” Buddhists, meanwhile, have endeavored for 2,500 years to overcome the suffering caused by our propensity for longing. Now, it seems, [neuroscientist Dr. Kent] Berridge has found the neuro-anatomical basis for this facet of the human condition – that we are hardwired to be insatiable wanting machines.

You likely have heard an abridged “cocktail party” version of some description of the mind’s reward system.  That version probably goes something like this: exposure to certain stimuli (candy, sex, exercise, cocaine) caused a release of dopamine in the mind, which the brain experienced as pleasure.  The brain then “learned” to seek out repeated exposure to that same stimulus so as to obtain the same dopamine release that it craved.  As time went on, each exposure to the stimulus caused the release of less and less dopamine, requiring greater and greater exposure to that stimulus to obtain pleasure.  So went the road to addiction, it was taught.

But Dr. Berridge has a different theory, based on his research beginning in the mid-1980s.

Berridge, a dedicated young scientist who was more David than Goliath, stumbled upon evidence in 1986 that dopamine did not produce pleasure, but in fact desire. […]

The reward system, he then asserted, has two distinct elements: wanting and liking (or desire and pleasure). While dopamine makes us want, the liking part comes from opioids and also endocannabinoids (a version of marijuana produced in the brain), which paint a “gloss of pleasure”, as Berridge puts it, on good experiences. […]

His most telling discovery was that, whereas the dopamine/wanting system is vast and powerful, the pleasure circuit is anatomically tiny, has a far more fragile structure and is harder to trigger.

Berridge’s insight was to distinguish the brain’s wanting from its actual experience of pleasure:

“It’s easy to turn on intense wanting,” he says.[…] “Massive, robust systems do it. They can come on with the pleasure, they can come on without the pleasure, they don’t care. It’s tricky to turn on the pleasure.” […]

“This may explain…why life’s intense pleasures are less frequent and less sustained than intense desires.”

Pleasure, Berridge explains, cannot be pursued relentlessly, as the mind’s own circuits are designed to produce satiety:

Wanting and liking wax and wane like candle flames. The hungry, wanting state before a meal could be studded with moments of pleasure from a social encounter, or anticipation of good food.  Then, as we eat, pleasure dominates, but wanting still crops up – more salt, a drink of water, a second helping. Before long, the satiety system steps in to render each mouthful less delicious until we stop. If we switch to another food – dessert, cheese, petits fours – we can prolong the pleasure until we’re stuffed, although we may regret it.

The applications of Berridge’s research that are most interesting to me are its implications on the current philosophical debates about free will.  This arises from Berridge’s conclusion that “it is possible to want something without liking it.”  Crazy impulse purchases, eating too much cake, continuing to drink or do drugs past the point of pleasure are all examples.  One must ask the question, who or what is making these choices for us?

Discussions of free will have arisen out of Berridge’s work because wanting and liking can happen both consciously and unconsciously. This is why urgent desires can be irrational and inconsistent, and fly in the face of what we know is best for us in the long run. Unconscious wanting can defy our best-laid plans to end an unhealthy relationship or not polish off that box of chocolates.

Berridge and his colleagues point to meditation as one cognitive tool to distance our conscious minds from the unconscious machinery of wants and needs:

[Berridge] was particularly struck by the effectiveness of meditation in taming our dopamine desires – not only among Buddhists.

Sarah Bowen, an addiction therapist in Seattle who was also invited on the Dalai Lama trip, has had significant success in helping recovering addicts by using mindfulness meditation. Over 12 months, this treatment reduced substance use more effectively than cognitive-behavioural therapy or the 12-step programme. It’s not a cure, and won’t work for everyone, because it requires commitment to get the benefits. But mindfulness’s tentacles are rapidly spreading throughout the Western world, perhaps because it’s one of the few palpable antidotes to the dopamine frenzy of modern life.

via Intelligent Life Magazine.

photo: cyclonebill from Copenhagen, Denmark, via Wikimedia Commons