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Study shows genes affect betting behaviour through dopamine regulation

The study, conducted jointly between UC Berkeley and UIUC, found that certain dopamine-regulating genes can influence our betting behaviour.

A study has found that the strategy and betting decisions of people who participate in competitive games like betting are partly influenced by their genes.

The study was carried out by researchers at the University of Illinois at Urbana-Champaign (UIUC) and the University of California, Berkeley. 

The researchers scanned 12 genes involved in the regulation of dopamine in the two main areas of the brain: the striatum and the medial prefrontal cortex.

Their findings showed that some genetic variants or mutations affect how bettors deal with trial-and-error learning. Other variants, on the other hand, affect how well players engage with and respond to the actions of others or the way others act.

The role of dopamine in gambling

The researchers found that specific variants of the dopamine-regulating genes in a person’s brain influence their betting decisions in simple competitive games.

Dopamine is a neurotransmitter that plays an important role in the way the brain responds to rewards and pleasure. When exposed to rewarding stimuli, the chemical is discharged by brain cells to send signals to others. 

A lack of dopamine results in Parkinson’s disease. Interference in the dopamine network is often associated with numerous neurodegenerative and psychiatric disorders, including depression, schizophrenia, and dementia.

Other studies have shown the crucial role that dopamine plays in social interactions. However, this is the first study that links these interactions to specific genes that control the way dopamine functions and how it affects social interactions.

The competitive parts of the brain

Ming Hsu, an assistant professor of marketing at the Hass School of Business at UC Berkeley, said that the study proves that genes have an influence on complex social behaviour and offers researchers clues about the neural mechanisms through which genes impact behaviours.

This study shows that genes influence complex social behaviour, in this case strategic behaviour… We now have some clues about the neural mechanisms through which our genes affect behaviour.

Ming Hsu, Hass School of Business at UC Berkeley

Hsu proved that when participants engage in betting games and other similar competitive social interactions, they utilise two primary areas of the brain.

The first is the medial prefrontal cortex, which acts as the executive part of the brain and is heavily involved in decision-making. The second is the striatum, which contributes directly to multiple aspects of cognition, including motivation and reward perception.

When bettors were observed through functional magnetic resonance imaging (MRI) scans, the researchers found intense activity displayed in these areas. One thing Hsu found interesting was that the nerves in these two areas were stimulated by neurons that use dopamine.

When one thinks of the brain as a computing machine, these two areas take inputs, run them through an algorithm, and interpret them into behavioural outputs.

To find out which dopamine-regulating genes in the two brain areas were linked to strategic thinking, researchers enlisted more than 200 undergraduates at the National University of Singapore.

The undergraduates participated in a competition called the patent race. Social scientists often use this game to study social interactions. It involves a person betting with an anonymous opponent via a computer.

The participants had their genomes scanned for about 700,000 genetic variants. Of that number, the researchers spotlighted only 143 mutations within 12 dopamine-regulating genes.

Out of the 12 genes observed, some were primarily involved in dopamine regulation in the prefrontal cortex; others primarily regulated dopamine in the striatum.

Based on findings from brain imaging studies, it is known that people engage in two clear-cut types of learning processes when competing against one another: reinforcement and belief learning. 

On the one hand, reinforcement learning involves learning purely from the consequences of your actions — how quickly you forget past experiences and change your strategy. On the other hand, belief learning is the degree to which people can make a mental model of other players to enable them to anticipate and respond to their actions.

Trial-and-error reinforcement learning vs belief learning

Set and Hsu discovered a distinct difference between the performances in belief learning and reinforcement learning. To achieve this, they used a mathematical model of brain function during combative social interactions with different variants of the 12 genes involved in dopamine regulation. 

The researchers found that the differences in belief learning were linked to mutations in the three genes that primarily affect the way dopamine functions in the medial prefrontal cortex.

On the contrary, the differences in trial-and-error reinforcement learning were associated with mutations in two genes that primarily affect dopamine functioning in the striatal area in the brain.

Hsu said these findings correspond with other brain studies, which prove that the prefrontal cortex is involved in belief learning and the striatum deals with reinforcement learning. Regardless of the outcome of the study, there are betting sites in Indonesia that continue to operate and make use of betting behaviours, even when offline casinos are banned.

Though Hsu states that the researchers were surprised by the amount of overlap observed, the findings indicate the power of studying the neural and genetic levels under a single mathematical framework, which is only beginning in this area.

Unending yet uncertain possibilities

The findings may also alter the way we see diseases like schizophrenia that directly involve dopamine, as well as social interaction disorders like autism.

Schizophrenia is one of the first diseases people think of when speaking about dopamine dysfunction. Hsu notes that the complex mental disorder involves a sequence of deficits in decision-making and social interactions.

These findings will help the researchers to better understand prevailing social interactions in specific settings. It will also enable them to characterise and, eventually, treat the special deficits that are symptomatic of diseases like schizophrenia more efficiently.

Chidirim Ndeche

Chidirim Ndeche is a reporter at Breakthrough.

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