By Christian Jarrett

The traffic lights turn amber: should you brake or accelerate on through? If there’s a teenager at the wheel, the chances are he or she will put their foot down and keep going. Teenagers love taking risks, more so than any other age group. This is partly down to the immaturity of the teen brain: they do not yet show the same connectivity between frontal decision making areas and deeper reward-related brain areas, as compared with adults. But there’s also a social element. When an adult is around, teens tend to take fewer risks, and their brains show less reward-related activity after taking a risk, a phenomenon that psychologists call “social scaffolding” because it is as if the adult presence is helping the teen to attain adult-like behaviour. A new study in Developmental Science builds on these findings and makes the claim that a teenager’s brain is influenced to a greater extent by the presence of his or her mother than by an unfamiliar adult.

João Moreira and his colleagues scanned the brains of 23 15-year-olds (9 girls) while they played a risk-based game that involved going through a set of 26 traffic lights as quickly as possible and deciding at each set whether to accelerate or brake as the lights turned amber. Accelerating saved time usually, but also carried the risk of a crash which would lead to a greater delay than braking. The teens played the game twice: once in the presence of their mother who was located in the scan control room, and the other time in the presence of an unfamiliar female professor who was described as an expert in adolescent driving behaviour (some played the game with mum present first, others with the stranger present first).

There was a tendency for the teens to take fewer risks when their mum was present, as compared with the professor, but this difference didn’t reach statistical significance. However, at a neural level there were statistically significant differences between the conditions: when mum was present, the teens’ brains showed more reward-related brain activity after making safe decisions and less reward-related brain activity after making risky decisions. Mum’s supervision seemed to make caution a more pleasurable approach, at least at a neural level.

There was also an important difference between conditions in terms of the functional connectivity between decision making and reward-related brain regions in the brain. In the mum condition, but not the adult stranger condition, there was a negative correlation in the activity between these regions: a more mature pattern typical of that seen in adults.

Finally, the teens’ brains showed more activity in regions associated with perspective-taking when taking risks in the mum condition, perhaps suggesting they were concerned with what she might think.

The researchers interpreted their findings as suggesting there is something unique about the influence of a parent (or a mother, at least) on the way a teenager’s brain processes risk, which could have practical implications. For example risk-prevention educational programmes for teenagers, which often struggle to make a difference, might be more likely to be effective if parents are directly involved.

Unfortunately, the study is hampered by several methodological issues such as the small sample size and the lack of a baseline control condition: the latter means it’s not clear if differences between the conditions are caused by the benefits of a mother’s presence or the opposite effect of an unfamiliar adult. Also, many issues are left unanswered, such as: would a father have the same apparent effect as a mother? And does the quality of the parent-teen relationship matter?

—Mother still knows best: Maternal influence uniquely modulates adolescent reward sensitivity during risk taking

Christian Jarrett (@Psych_Writer) is Editor of BPS Research Digest