Why do humans take risks? And what makes people more or less likely to engage in risky behaviour? It seems that taking risks is largely down to a powerful brain chemical.
The Neurochemistry of Taking Risks
Dopamine is a neurotransmitter. Neurotransmitters are chemicals that neurons use to send signals to each other. Dopamine has several roles in the brain, but one of the most infamous is its role in the reward system.
Dopamine regulates feelings of pleasure. It has been called the feel-good hormone because our brains reward us by releasing it. It’s thought that dopamine helps to shape our behaviours to seek rewards and avoid punishments. It signals the difference between the rewards we expect and the rewards that we experience.
Yet dopamine is more than just a feel-good hormone. It helps us to focus, it is involved in how social we are, it helps us to move, it plays a role in how well our working memory functions and more. Each neuron has several receptors that take in dopamine, these receptors are called D1 to D5.
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Novelty seekers tend to engage in more risky behaviour. It was discovered that rats who were novelty seekers had fewer receptors of the type D2. This receptor inhibits dopamine and acts to lower dopamine levels in the brain. A study led by David Zald looked at whether the same was true for humans.
Using brain scans the researchers tested 34 people who had been assessed for their novelty seeking traits. The results showed that people who take more risks have fewer D2 (or D2-like) receptors. In other words they have more dopamine swashing around in their heads.
Dopamine and Parkinson’s Disease
Dopamine plays an important role in starting movement. Parkinson’s disease occurs when certain neurons in the brain either die or don’t work effectively. In the brain, one region called the substantia nigra connects to another called the corpus striatum to allow us to move smoothly. If brain cells die in these regions then they can’t produce dopamine. These lower dopamine levels cause the jerky uncontrolled movements typical of Parkinson’s Disease.
Dopamine Replacement Therapy is designed to boost the levels of dopamine to ease the symptoms. Unfortunately it comes with a side-effect. Higher dopamine levels can lead to higher risk taking behaviour in patients with Parkinson’s. In fact, raising dopamine levels significantly increases the risk of pathological gambling.
Dopamine and Healthy Adults
A study by University College London did an experiment on thirty healthy adults. The participants played a game where they could win or lose money. They were given the choice of either accepting a small loss or to gamble on a 50/50 chance of losing nothing or losing more. At other times they could accept a small win or gamble on a bigger win with an equal chance of winning nothing. Everyone played these games twice. Once after taking a drug (L-DOPA) to boost their dopamine levels, and once after taking a placebo.
The researchers found that boosting dopamine levels made the potential rewards more appealing. People were as happy with small and large winnings, whereas people with normal levels of dopamine felt happier after winning a larger amount. People who took L-DOPA choose more risky options no matter how big the reward, but interestingly, they did not take more risks when there were potential losses.
So it seems clear that dopamine is a big factor in taking risks. It seems that small and big rewards make people equally happy when they have elevated dopamine levels.
Novelty seeking and risk taking personality traits are linked to unsafe sexual behaviour, gambling and drug taking. Higher amounts of dopamine seems to blur the lines between small and big rewards. Interestingly it appears to not increase risk taking when there are potential losses so there may be other factors at play with people suffering from addiction. In the study of Parkinson’s patients, those with a family history of addiction were more likely to engage in uncontrolled gambling than others. So dopamine only provides us with a glimpse of the big picture.
Of course, taking risks is not necessarily a bad thing (provided they are calculated risks). Indeed, it could be argued that progress relies on people taking risks!
Are you a risk-taker? Do you think your dopamine levels are high?
News-Medical – Dopamine Functions
NCBI – Midbrain dopamine receptor availability is inversely associated with novelty seeking traits in humans
NCBI – The role of dopamine in risk taking: a specific look at Parkinson’s disease and gambling