that the parasitic enemy shouldn’t be exterminated. This is where scientific explanation gains considerable interest, helping us understand how we develop anticipatory pleasures and past-oriented regrets, struggle to change from habitual rewards, and acquire irrational desires for experiences we no longer enjoy — a problem that appears to maintain most forms of addiction.
Humans go to restaurants and bees to flowers because both are associated with food. Within these broad categories, there are good restaurants and flowers, as well as bad ones, where good and bad are determined by experience. The experience can be direct, as when food 1s actually consumed, or indirect as when humans listen to an animated friend describe a restaurant’s menu and bees watch a hive mate dance, providing a description of the flower’s location and quality. Once the association between food and location is established, simply seeing the restaurant or flower triggers a cascade of neural and chemical activity in the brain linked to reward and the anticipation of pleasure. The restaurant and flower are cues that predict food. If you walked into your favorite restaurant and found that they sold fertilizer rather than food, you would be heartbroken. If you haven’t been to the restaurant in a long time, but memorialized your previous experience as a gastronomic high, you will be deeply disappointed if your first bite doesn’t live up to the standards you anticipated. This mismatch between anticipated and experienced reward will lead to a cascade of brain activity — indicative of an error. The primary engine driving the experience of reward, including predicting when it will occur and with what kind of intensity, is the dopaminergic system, a network of brain areas that releases dopamine in most invertebrates and vertebrates, including the human vertebrate.
Many natural behaviors trigger dopamine, including male songbirds singing to attract females, rhesus monkeys seeing a red light that has been associated with a soon to be delivered shot of juice, and humans cooperating with each other. Many unnatural behaviors and objects can also trigger dopamine. Animals trained to press a switch for food, will often become obsessively attracted to the switch, caressing and biting it even in the absence of food; humans with addictions to cigarettes, food and gambling, will often obsessively fondle an empty cigarette carton, fork, and deck of cards, respectively. But these correlations leave open the question of whether dopamine causes the anticipation or experience of reward, or flows from these experiences.
To tackle the causality problem requires experiments, either directly changing dopamine concentration or comparing individuals who, due to genetic differences, show differences in dopamine levels. We know from studies of rodents and monkeys that selectively increasing dopamine with drugs results in heightened wanting of food if there are cues to foraging, or sex if opportunity knocks. The Israelian cognitive neuroscientist Tali Sharot pursued a similar approach with healthy humans subjects. She first asked individuals to rate how happy they would be if they vacationed in 80 possible destinations.
Then, some subjects took a placebo while others took L-dopa, a drug that selectively increases the release
Hauser Chapter 2. Runaway desire 61
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