Key research: Barkley-Levenson and Galvan (2014) Neural representation of expected value in the adolescent brain

Aim To identify if there was neural activity between adolescents and adults when giving risk-taking scenarios. Sample 19 adults aged 25 to 30 (adult group) 22 adolescents aged 13 to 17 (adolescent group) All participants were right-handed. All were recruited by volunteer sample at the University of California. No previous diagnoses of mental illness. No metal in their bodies (e.g. pacemaker). Only 20 adolescents and 17 adults’ data was used with the others not providing useful data. [CE] Bullet points appear on a click

Procedure Participants all completed questionnaires about how they earn their money, how much they earn and how much they have to spend. This gave researchers an idea about their perceptions about winning and losing money. Participants were also familiarised with an MRI scanner. Participants then took part in a gambling task. [CE] Bullet points appear on a click

Gambling task Participants were given a spinner with a number of dollars that can be won or lost (e.g. one side might say ‘gain $2’ the other side might say ‘lose $4’). Using $20 that each participant was given at the start of the task, participants are told they could win another $20 or lose $20. There were 144 spinners with different combinations of amounts. Each participant had to take a risk with all 144 spinners. [CE] Bullet points appear on a click

Results Both adults and adolescents accepted gambles if the negative outcome was $0 rather than losing money (e.g. lose $4). The higher the amount that could be won, the more likely it was that the adolescent accepted the gamble. Adolescents showed significantly more activity in the left ventral striatum as the amount available to win increased. The right ventral striatum also showed greater activity in the adolescents. [CE] Bullet points appear on a click

Conclusion Adolescents showed significantly greater activation in the ventral striatum than the adults (who showed barely any activity at all). This could mean that the ventral striatum develops with age to decrease the amount of risk-taking behaviour. This suggests that adolescent brains place more emphasis on potential rewards than adult brains and the ventral striatum seems to be significant in heightening sensitivity to rewards. The brain then must undergo significant maturation in adulthood that reduces the sensitivity to rewards and therefore decreases the amount of risks adults take. [CE] Bullet points appear on a click

Application: Strategies to reduce risk-taking behaviours

Useful applications We know now many reasons why adolescents are more prone to risk-taking behaviour that could potentially be dangerous in the worst examples. Providing adolescents who are most likely to give in to risky behaviour with good education and social support will help them control their ventral striatum. Parents can talk to their children about the consequences of risk-taking behaviour and reduce risks for them (e.g. offering lifts in dangerous-to-drive roads). Positive social networks (good friends, school and community) can also help reduce risky behaviour. [CE] Bullet points appear on a click

Examples of applications One of the causes of risky behaviour is when a pregnant mother who suffers a large amount of stress has too much cortisol in her blood when giving birth to her baby. This stress is often due to a stressful environment around her (poor income, bad neighbourhood, etc.). Olds et al. (1998) carried out a programme that involved nurses visiting mothers before birth and providing training on how to cope with stressful situations. Results of this showed the children born at this time were more successful at school and showed lower rates of bad behaviour (possibly a reduction in risk-taking behaviour). Another strategy used to help adolescents was an age-appropriate learning curriculum which was adopted to educate teenagers about how to drive safely. New drivers were given a probationary period where their driving was restricted in certain ways (e.g. not being able to drive at night). This slow introduction to driving lowered the amount of new experiences to beginner drivers, therefore reducing the risk of starting driving than someone who could immediately drive with no restrictions. The programme saw a significant reduction in the crashes of adolescent drivers after about six months (McCartt et al. 2003). [CE] Bullet points appear on a click