Pre-adult brain development (Biological)

What you'll learn

• How the adolescent brain develops, especially the balance between reward and control systems.
• Why brain development can help explain risk-taking behaviour in young people.
• The key ideas, method, findings and evaluation of Barkley-Levenson and Galván (2014).
• How knowledge of brain development can be applied to reduce risky behaviour.

The big idea: why adolescence matters

In Child Psychology, pre-adult brain development looks at how the brain changes before adulthood and how those changes affect behaviour. The key behaviour here is risk taking: choices where a person may gain something rewarding, but could also experience harm or loss.

Adolescence is not just “being immature”. It is a developmental period where different brain systems change at different speeds. This matters because the systems involved in reward, emotion and self-control do not all mature together.

Examples include dangerous driving, unsafe sex, experimenting with drugs, binge drinking, antisocial behaviour or taking dares in front of peers.

Brain areas you need to know

The prefrontal cortex

The prefrontal cortex is the front part of the brain involved in planning, decision-making, impulse control and thinking about consequences. It develops gradually and continues maturing into early adulthood.

The limbic system

The limbic system is a group of brain areas involved in emotion, motivation and reward. Two important parts are:

• The ventral striatum, which is strongly involved in reward anticipation and motivation.
• The amygdala, which is involved in emotion, threat detection and emotional salience.

This is often called a dual systems explanation: one system pushes towards reward, while another system supports control and inhibition.

Expected value: making risk measurable

Barkley-Levenson and Galván’s study focuses on expected value. This is a way of estimating whether a risky choice is “worth it” by combining the size of the possible reward with the probability of getting it.

A gamble with a high reward is not automatically a good choice. If the chance of winning is very low, its expected value may still be poor.

Background: brain development and risk taking

The biological background to this topic is that adolescent risk taking may be linked to uneven brain development.

The prefrontal cortex supports controlled decision-making, such as delaying gratification, resisting peer pressure and considering future consequences. However, this region develops relatively slowly.

By contrast, reward-related areas such as the ventral striatum become very responsive during adolescence. This can make rewards feel especially attractive, particularly immediate rewards such as fun, social approval or excitement.

This helps explain why teenagers may understand the risks in theory but still take risks in real life. The issue is not necessarily ignorance. It may be that emotional and reward-based pressures are especially strong in the moment.

Key research: Barkley-Levenson and Galván (2014)

Aim

Barkley-Levenson and Galván (2014) investigated how adolescents represent the expected value of risky choices in the brain. They wanted to understand whether adolescent risk taking is linked to differences in neural activity during decision-making.

Method

This was a laboratory study using functional magnetic resonance imaging, usually shortened to fMRI.

Participants completed a decision-making task while inside the scanner. They made choices involving possible rewards, where the probability and value of the reward varied. This allowed the researchers to examine how participants responded to choices with different expected values.

The researchers compared adolescents with older participants, looking at both:

• Behavioural responses, such as whether participants accepted or rejected risky options.
• Neural responses, such as activity in reward-related and control-related brain regions.

Results

The study found that adolescents were sensitive to expected value, meaning they were not simply choosing randomly or failing to understand the task.

However, adolescents showed differences in how expected value was represented in the brain. Reward-related regions, especially areas such as the ventral striatum, were important in adolescent decision-making.

The findings support the idea that adolescent risk taking is linked to heightened reward processing and developing control systems. Adolescents may be especially drawn to rewarding options, particularly when rewards are immediate or emotionally engaging.

Conclusions

Barkley-Levenson and Galván concluded that adolescent risky decision-making has a biological basis. Differences in brain development affect how young people evaluate rewards and risks.

This does not mean adolescents are incapable of rational decision-making. Instead, it suggests that their brains may process reward and value differently from adults, especially in situations involving immediate incentives.

AO3 evaluation of Barkley-Levenson and Galván

Strength: scientific and objective

A major strength is the use of fMRI. Brain activity provides biological evidence rather than relying only on self-report. This supports psychology as a science because the study used controlled procedures and measurable data.

However, fMRI does not directly measure thoughts. It measures blood oxygenation, so researchers must infer what brain activity means.

Strength: useful applications

The research is useful because it helps explain why risk-taking interventions should not just give teenagers information. If adolescent risk taking is partly driven by reward sensitivity, then strategies should reduce immediate temptations or increase support for self-control.

For example, road safety campaigns may be more effective if they reduce peer pressure and immediate rewards, rather than only warning teenagers that dangerous driving is risky.

Weakness: ecological validity

The task took place in an fMRI scanner, which is very different from real-world risk taking. Real adolescent risks often involve friends, emotion, alcohol, status, embarrassment or time pressure.

This means the study may have limited ecological validity, which is the extent to which findings reflect real-life behaviour.

Weakness: reductionism

The explanation is biologically reductionist because it focuses on brain regions and neural activity. This is useful for identifying mechanisms, but it may underplay social and cognitive factors.

For example, peer pressure, parenting style, school environment, culture and individual personality can all influence risk taking.

Ethics

Because brain research can involve young participants, ethical safeguards are very important. Researchers should follow the BPS Code of Human Research Ethics, including informed consent, protection from harm, right to withdraw, confidentiality and additional care when working with under-16s.

In this kind of study, participants would need to be screened for MRI safety and warned that scanning can be noisy or uncomfortable. For younger participants, parental consent and the young person’s own assent would be needed.

Application: reducing risk-taking behaviour

If adolescent risk taking is partly caused by a reward-control imbalance, then interventions should help the developing prefrontal cortex “win” against immediate reward pressure.

Strategy 1: reduce hot decision-making

A hot decision is made in an emotional, exciting or socially pressured situation. A cool decision is made calmly, with time to think.

One strategy is to design environments so adolescents make important choices in cool states rather than hot states.

Examples include:

• Graduated driving licences that limit night driving or peer passengers for new young drivers.
• Pre-commitment plans, such as agreeing transport home before going to a party.
• Phone apps or banking controls that delay impulsive spending or risky online behaviour.
• School-based role play that practises refusal skills before the real situation occurs.

Strategy 2: increase cognitive control

Another strategy is to strengthen decision-making skills. This might involve teaching adolescents to pause, compare outcomes and plan responses before risky situations occur.

This fits the biological explanation because it supports prefrontal cortex functions such as planning, inhibition and future thinking.

Linking to wider debates

Nature and nurture

The topic clearly supports nature because it focuses on brain maturation. However, it also allows for nurture, because social settings can increase or reduce risky behaviour. For example, peers may intensify reward, while supportive rules may reduce risk.

Free will and determinism

The explanation is partly biologically deterministic because brain development influences behaviour. But it is not fully deterministic: adolescents can still make choices, and interventions can change the environment.

Usefulness

This is a highly useful topic because it can inform education, parenting, public health and law. It suggests that effective policies should account for adolescent brain development rather than simply blaming young people for being reckless.