Brain development & Risk taking behaviour (Dual-systems theory…
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.
Adolescents would be more sensitive than adults to increased EV (by accepting more gambles
Adolescents would show greater VS activation as EV increases
Adolescents would show higher VS activation than adults 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
Sample: 19 adults (aged 25-30) and 22 adolescents (aged 13-17), all right handed. Self-selected sample
fMRI scans were used to look at activity in the ventral striatum
Intake session: ppts given details about their monthly spending and where it came from. Significant mean difference in spending- $467.11 for adults and $52.50 for adolescents.
Ppts were 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: Each participant completed a gambling task. They were shown an on screen spinner with two halves, one with a winning value on and one with a losing value, therefore gain/loss probability was 50%
48 of the 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