Brain development & Risk taking behaviour (Barley-Levenson &…
Brain development & Risk taking behaviour
Our brain develops in a 'bottom up' way- begins with basic structures essential for survival and later becomes more complex and advanced
amygdala, and closely associated with the ventral striatum- controls emotional responses. Develops throughout childhood and adolescence
: a few millimetre thick layer over the brain where thinking takes place. Frontal cortex- controls high order thinking such as problem solving. controls sensory information in the visual and auditory cortex. Extensive development in early years
process by which new synapses are formed between neurons. They attribute to numbers of neurotransmitters which are important in cognitive processes, such as thinking.
process by which the necessary synaptic connections are kept. Those neurons used more often have a greater neurotransmitter activity, thus are stronger and remain. Those which are used less often are pruned. This creates organisation in the brain to allow for special functions.
Suggests risk-taking behaviour in adolescence is directed by the interaction of two brain systems that mature at different times: ventral striatum and prefrontal cortex
key component for reward and pleasure in the brain, and has greater activity in adolescence. it is controlled by changes in the neurotransmitter dopamine that is responsible for mood
associated with high order thinking, decision-making and the ability to risk-assess. It is slower to develop, and undergoes synaptic pruning- reaches maturity at young adulthood.
The imbalance between the two systems only occurs during adolescence and can explain risk-taking behaviour- the pre-frontal cortex has no control over the ventral striatum because it is not fully developed during these years.
Barley-Levenson & Galvan
: Investigated the effect of gambling and activation in the ventral striatum with adolescents compared to adults. They looked at how much value we place on an object (subject value) and expected value in response to activation on the ventral striatum
increasing EV made gambling more likely- greater in adolescence. Gambling acceptance did not change for the gain-only/loss-only trials for either group- adolescence behaved like adults when there was no risk.
fMRI scans- as EV increased, so did activation in the superior medial and decreased in amygdala and hippocampus. Increased activation in the left VS for adolescence.
: Adolescents would be more sensitive than adults to increased EV (by accepting more gambles). Adolescents would show greater VS activation as EV increases. Adolescents- higher VS activation even when matching on the same number of accepted gambles
: Laboratory-based quasi experiment using independent measures. IV-adolescent or adult. DV- number of gambles accepted by ppt and activity in the ventral striatum. 19 adults (aged 25-30) and 22 adolescents (aged 13-17), all right handed, self-selected. fMRI scans- looked at activity in the ventral striatum.
the adult brain shows a heightened sensitivity towards reward- shown by increased activation in the pre-frontal cortex and ventral striatum. The adolescent brain therefore places greater value on potential rewards.
: Intake session- ppts given details about their monthly spending. Spending- $467.11 for adults and $52.50 for adolescents. Given $20 as playing money to be used in the next session. Told they could win another $20, but could also lose the money they already had. fMRI session- completed a gambling task. They were shown a spinner with two halves, one with a winning value on and one with a losing value, therefore gain/loss probability was 50%. 48/192 trials had a 100% gain/loss fixed outcome. Participants knew this- choosing to gamble on these trials did not show risk-taking behaviour. This was to allow for a wider range of EV's- ranged from +$7.50 to -$7.50 for the mixed trials and +/-$6 t0 $19 for the fixed trials
Graduated Driver Schemes
Used to reduce the risk of accidents in experienced drivers, typically teenagers, who's brain is governed by the ventral striatum that leads to underdeveloped cognitive skills crucial to driving (distance judgement, speed, decision- making)
Researchers have suggested adolescent driving involving friends is highly prone to risk-taking behaviour- such schemes discourage this combination or at least make drivers aware of its effects
Under the programme, driver's cannot get a full license until they have completed an extended period of supervising with an experienced adult- support is gradually removed when certain stages are passed e.g fully supervised, non-supervised in day-light, and then full privileges after passing the stages and turning 18.
Usefulness: restricts the number of passangers in the car, especially friends who create a heightened physiological arousal making risk-taking behaviour more likely. The use of the extended supervision had been proven to reduce risky driving