- Scientists
wanted to find the genes linked to behaviour driven by past experience
and behaviour caused by anticipating the reaction of others
- By
analysing the brains of volunteers involved in a competitive game, the
researchers matched up mutations of 12 dopamine-related genes
- Dopamine is a chemical released by brain cells to signal other brain cells
- The study suggests gambling decisions are influenced by genetic make upGamblers are born and not made, according to a Californian study that claims strategic betting behaviour is biological.
The
study found that gambling decisions in a simple competitive game were
influenced by specific dopamine-regulating genes in a person’s brain.
Dopamine
is a neurotransmitter - a chemical released by brain cells to signal
other brain cells - that is a key part of the brain’s reward and
pleasure-seeking system.
Gamblers are born and not made, according to a Californian study that
claims strategic betting behaviour is biological. The study found that
gambling decisions in a simple competitive game were influenced by
specific dopamine-regulating genes in a person's brain
SCIENTISTS FIND THE PART OF THE BRAIN INVOLVED IN GAMBLING
Research
in April revealed that brain damage affecting the insula – an area with
a key role in emotions – disrupts errors of thinking linked to gambling
addiction.
During
gambling games, people often misperceive their chances of winning due to
a number of errors of thinking called cognitive distortions.
For example, 'near-misses' seem to encourage further play, even though they are no different from any other loss.
For
the study, researchers from the University of Cambridge gave patients
with injuries to specific parts of the brain two different gambling
tasks.
This included a slot machine game that delivered wins and 'near-misses', and a roulette game involving red or black predictions,
Control
groups featured patients with injuries to other parts of the brain, as
well as healthy participants undergo the gambling tasks.
All
of the groups, with the exception of the patients with insula damage,
reported a heightened motivation to play following near-misses in the
slot machine game, and also fell prey to the gambler's fallacy in the
roulette game.
It is also the major chemical in the body blamed for an individual's' proclivity to gamble.
Previous
studies have shown that when people engage in competitive social
interactions, such as betting games, they call upon two areas of the
brain: the medial prefrontal cortex, which is the executive part of the
brain, and the striatum, which deals with motivation.
'What is really interesting
about these areas is that both are innervated by neurons that use
dopamine,' said Dr Ming Hsu, an assistant professor of marketing in
University of California Berkeley’s Haas School of Business.
Dr
Hsu wanted to determine which genes involved in regulating dopamine
concentrations in these brain areas were associated with gambling
behaviour.
They
enlisted a group of 217 undergraduates at the National University of
Singapore, all of whom had had their genomes scanned for some 700,000
genetic variants.
The researchers focused on only 143 variants within 12 genes involved in regulating dopamine.
Some
of the 12 are primarily involved in regulating dopamine in the
prefrontal cortex, while others primarily regulate dopamine in the
striatum.
The competition
was a game called patent race, commonly used by scientists to study
social interactions. It involves one person betting, via computer, with
an anonymous opponent.
'We
know from brain imaging studies that when people compete against one
another, they actually engage in two distinct types of learning
processes,' said student Eric Set, who was also involved in the study.
Previous studies have shown that when people
engage in competitive social interactions, such as betting games, they
call upon two areas of the brain: the medial prefrontal cortex (shown
here in pink), which is the executive part of the brain, and the
striatum (shown by the light blue dot), which deals with motivation
Brain scans show high activity in the medial prefrontal cortex (top) and striatum (bottom) while playing a competitive game
'One type involves learning purely from the consequences of your own actions, called reinforcement learning.
'The
other is a bit more sophisticated, called belief learning, where people
try to make a mental model of the other players, in order to anticipate
and respond to their actions.'
Using
a mathematical model of brain function during competitive gambling, the
researchers matched up performance in reinforcement learning and belief
learning with different variants or mutations of the 12
dopamine-related genes, and discovered a distinct difference.
They
found that differences in belief learning – the degree to which players
were able to anticipate and respond to the actions of others – was
associated with variation in three genes which primarily affect dopamine
functioning in the medial prefrontal cortex.
In
contrast, differences in trial-and-error reinforcement learning – how
quickly they forget past experiences and how quickly they change
strategy – was associated with variation in two genes that primarily
affect striatal dopamine.
Dr
Hsu said that the findings correlate well with previous brain studies
showing that the prefrontal cortex is involved in belief learning, while
the striatum is involved in reinforcement learning.
'We
were surprised by the degree of overlap, but it hints at the power of
studying the neural and genetic levels under a single mathematical
framework, which is only beginning in this area,' he said.
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