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TOO MUCH OF A GOOD THING
“In the beginning everything was even money” – Mike Caro
This quote by the mad genius of poker Mike Caro is equally applicable to the battle for survival and to the game of poker. Like poker players, individuals struggling for survival in nature must figure out which actions are likely to lead to rewards (food, sex, shelter) and which will lead to punishments (starvation, death at the hand of a predator). Through trial and error, all animals that have the capacity to make decisions (i.e. all animals that have a nervous system) learn to maximize their chances of obtaining rewards.
However, that is not the end of the story. Merely knowing where the food and the predators are hiding is not enough. Think of a small animal in its burrow, deciding whether or not to go out into the open field to look for food. In the short term, if there are predators about, staying put is always the best option, but that means death and extinction in the long run. Similarly, a tight conservative strategy in a poker tournament will allow a player to last longer, while essentially ensuring that he or she will not win in the long run. In the struggle for survival and in poker, acting with drive and vigour is the only successful long-term strategy. This is where drive, motivation and appetite come in.
The brain systems responsible for learning from rewards and punishment are also the ones that control motivation. Motivation means not merely going for rewards, but being willing to expend great effort and take risks in their pursuit. Central to this process is a chemical called dopamine. Dopamine is a neurotransmitter that allows neurons to communicate with one another. My lab uses brain imaging to study the role of dopamine in appetitive behaviours, whether normal (eating) or pathological (drug addiction, pathological gambling).
Ironically, the world we have created to satisfy our appetites is also a major cause of ill health. The top killers in the western world, such as cancer, heart disease and diabetes, are essentially caused by excessive appetite: smoking, obesity, alcoholism. There is recent evidence that obesity plays a role in certain neurodegenerative diseases like Alzheimer’s and Parkinson’s diseases.
Stress is part of the story that we study. While we usually think of stress as being what we experience before exams or important life events, in the original, 19th century definition stress was seen as a deviation from a “homeostatic set-point” such as a signal that the body was missing food, for example. Stress signals, then, influence the function of drive and reward systems in the brain. It is not surprising then that stress is a major player in addiction and obesity – one that too often draws the winning cards.
For further reading:
A. Dagher, T. Robbins. Personality, Addiction, Dopamine: Insights from Parkinson's Disease. Neuron, Volume 61, Issue 4, Pages 502-510.
