Topic 2; Levenson

Question 1

what is the aim?

Answer 1

to investigate whether adolescents place more value on rewards than adults do and to identify neural development of expected value in the brains of adolescents

Question 2

what does expected value mean?

Answer 2

is the sum of all of the possible outcomes of a particular choice multiplied by their probabilities - a person uses this to judge whether the risks are worth taking in order to gain a reward

Question 3

what is the sample?

Answer 3

• 19 adult participants between the ages 25 and 30
• 22 adolescent participants between the ages 13 and 17
• recruited from poster and internet advertisements

Question 4

what is the design of this study?

Answer 4

quasi experiment under laboratory conditions

Question 5

what is the procedure?

Answer 5

• the independent variable was the age of the participants
• the dependent variable was the differences in neural activity and behavioural responses to a gambling task
• participants’ source/amount of income was collected to investigate whether the differences between the two groups was due the novelty of the reward rather than developmental differences
• when undergoing an fMRI scan, participants were given $20 playing money - they were informed that they could possibly earn more money or potentially lose it
• participants were presented with a series of gambling tasks across 144 trials; there was a 50% chance that they would lose or gain $5-$20
• neural activity in response to the gambling task was observed and recorded using an MRI scanner and behavioural responses of acceptance and rejection was recorded too

Question 6

what was the findings in relation to neural activity?

Answer 6

• more activity in the ventral striatum of adolescents when the expected value increased; this was still the case when participants were matched on income and overall acceptability of gambles, suggesting that adolescents do not have a special preference for money
• even when gambling behaviour was similar across both groups, there was still more activity in the ventral striatum of adolescents

Question 7

what was the findings in relation to the different behavioural responses?

Answer 7

• in trials where no risk was involved, judgements made were similar for both groups
• an increase in the expected value increased the likelihood of accepting the gamble for both groups but this was still more prominent in adolescents
• this hyperactive rewards sensitivity suggests that adolescents were more focused on the higher amount they could win and less concerned with the smaller amount they could lose
• both groups never accepted a gamble with a lower expected value

Question 8

what were the conclusions of this study?

Answer 8

• adolescents placed greater value on rewards than adults do
• neural representations of value in adolescents are linked to increased risk taking behaviour
• adolescents behave similarly to adults when there is no risk involved

Question 9

what are the strengths of this study?

Answer 9

• high level of internal validity; computerised task which makes the procedure objective
• high level of reliability; standardised, can be easily replicated, participants are likely to have a similar experience
• useful to help understand how the brain develops and the hyperactive reward sensitivity explains why adolescents are more likely to engage in risk taking behaviour

Question 10

what are the weaknesses of this study?

Answer 10

• highly controversial; could be argued that the gambling task could encourage gambling outside the study, especially if there is a reward of real money #
• the sample lacks population validity; both groups are small and Levenson didn’t provide a pre-adolescent group which would improve population validity
• lacks ecological validity; computerised task with the use of fake money
• reductionist; only uses the ventral striatum as an explanation for risk taking behaviour