A new study by Berna Güroğlu and her colleagues tracked changes in the adolescent brain to discover the motivation behind novelty seeking.
Adolescents have a strong tendency to seek out new and exciting experiences — a trait called novelty seeking — which can serve as a double-edged sword. Novelty seeking can lead to increased risk-taking behavior such as substance abuse or reckless driving, but it also remains the cornerstone of normal explorative behavior and learning.
One of the driving factors behind this urge for adventure during adolescence is a developmental change in how the brain responds to rewards. The teenage brain has a heightened response to novel stimuli, which leads these individuals to seek out more new and possibly risky experiences.
To better understand how the brain develops during this period, a new longitudinal study by Elisabeth Schreuders and colleagues tracked changes in the brain region involved with reward processing across adolescence and early adulthood. Researchers from Leiden University scanned participants using functional magnetic resonance imaging (fMRI) at three time points, each separated by two years. The results, published in March 2018 by Child Development, confirmed that brain activity to rewards peaks in mid-adolescence.
“The fact that we find an age-related increase in the neural pattern that responds to rewards shows that adolescents become increasingly sensitive to rewards,” said co-author Berna Güroğlu, professor in the Developmental and Educational Psychology unit of the Institute of Psychology at Leiden University. “This increase goes on until about mid-adolescence — around age 16 — so until then we can say that adolescents might have an increasingly difficult time to keep these impulses under control.”
Güroğlu and her colleagues collected data from 299 participants as part of the Brain Time longitudinal study, which aims to track structural and functional brain development over time. The participants ranged in age at the first time point from 8 to 25 years. Participants played a game in the scanner where they guessed if a coin would land on heads or tails. If they guessed correctly, they won money, whereas if they guessed incorrectly, they lost money.
The fMRI measured the brain’s neural activation during winning. The authors focused in on a brain region called the nucleus accumbens, an area strongly involved in reward processing. They found that activity in this region increased from age 8 onwards, peaking in mid-adolescence around age 16, and then decreasing throughout early adulthood.
“Different motivational factors might play a role in novelty seeking depending on age.”
In addition, the authors wanted to explore the link between this neural response and two types of reward sensitivity measured at the behavioral level. The first type, called state-level reward sensitivity, looks at how much hedonic pleasure a person feels in the very moment of receiving a reward. The second type, trait-level reward sensitivity, is a measure of a person’s general drive to pursue and obtain rewards.
Participants indicated how much pleasure they experienced while winning and losing money in the game — a measure of state-level reward sensitivity. Additionally, participants filled out a questionnaire that asked about their general tendency to seek out rewards, which indicates trait-level reward sensitivity.
“We found that the increase of brain activity in early to mid-adolescence is related to trait-level reward sensitivity, whereas the decrease in mid-adolescence to early adulthood is related to state-level reward sensitivity,” said Güroğlu. “So the developmental changes in the neural response to rewards can be best explained by different aspects of reward sensitivity in different phases of adolescence.”
“A better understanding of the motivational and neural factors of explorative behavior could ultimately be used to help adolescents become successful adults.”
The findings suggest that different motivational factors might play a role in novelty seeking depending on age. From early to mid-adolescence, higher levels of a self-reported drive to pursue and achieve personal goals were associated with stronger activity in the nucleus accumbens. In older adolescents and young adults, less pleasure was gained from receiving rewards, and this was associated with reduced levels of activity in the nucleus accumbens.
Güroğlu believes these results contribute to better understanding the motivational and neural factors of explorative behavior, which could ultimately be used to help adolescents become successful adults.
The purpose of the annual Flux Congress is to advance the understanding of human brain development by serving as a forum for professional and student scientists, physicians, and educators to: exchange information and educate the next generation of developmental cognitive neuroscience researchers; make widely available scientific research findings on brain development; encourage translational research to clinical populations, and encourage further progress in the field of developmental cognitive neuroscience. This year’s Flux Congress took place in Berlin, Germany.
Berna Güroğlu was among the speakers at the congress.