As many of us can remember, adolescence is a stage of life marked by contradictions. Teens are treated like adults in some cases and like children in others. Teenagers are often told to “act their age,” but there is clearly a lot of confusion (for both adults and teens) about what exactly that means. When exactly do we go from children to adults? The answer is simply (and confusingly) that it depends.
In Adolescents’ Cognitive Capacity Reaches Adult Levels Prior to Their Psychosocial Maturity: Evidence for a “Maturity Gap” in a Multinational, Cross-Sectional Sample Icenogle et al. (2019) assess two different indicators of adulthood: cognitive capacity and psychosocial maturity. Cognitive capacity refers to the ability to think logically i.e., “cold” cognition, while psychosocial maturity refers to the ability to make sound decisions during highly emotional situations i.e., “hot” cognition. It has been found in previous research that these two types of maturity develop at separate times in life, with cognition reaching adult levels at around age 16. In contrast, psychosocial maturity continues to develop during the early 20s (Steinberg 2009). Being aware of this “maturity gap” can help governments better develop majority ages for different legal purposes, such as driving, consuming alcohol, and plea bargaining (previously discussed here).
In this study, the researchers collected data from 5,404 participants between the ages of 10 and 30 from eleven different countries, namely China, Colombia, Cyprus, India, Italy, Jordan, Kenya, the Philippines, Sweden, Thailand, and the United States. The diversity of countries and cultures was designed to improve the generalizability of previous research as much of it has focused on Western countries only. Each participant completed a series of tasks designed to assess cognitive capacity and psychosocial maturity. The cognitive tasks included working memory and verbal fluency tests, while the psychosocial tasks largely measured self-restraint.
It was hypothesized that cognitive capacity would reach adult levels prior to age 18 while psychosocial maturity would continue to develop after age 18 and into the 20s. The researchers also hypothesized that there would be differences in psychosocial maturity age trends from one country to the next, but that cognitive capacity age trends would be more or less consistent. The results were consistent with previous research in that the sample at large followed the predicted “maturity gap” trends. There was a statistically significant cubic trend in which cognition improved drastically from childhood to adolescence but tapered off after age 16. Psychosocial maturity showed a linear trend where maturity continues to improve from childhood and into adulthood. However, the results also showed that both cognitive capacity and psychosocial maturity age trends differ between countries. For example, in China, Colombia, India, and Thailand, cognitive capacity showed a cubic trend but also another slight increase in the late 20s. Colombia also showed a cubic trend in psychosocial maturity until the mid-20s, but then declined. Although these variations are likely due to cultural differences, it is difficult to determine the exact cause as the countries that did and did not follow predicted trends were diverse in terms of being western versus eastern and individualistic versus collectivistic.
The importance of determining the ages of majority for different legal purposes such as driving a car, drinking alcohol, and consenting to medical procedures is evident. However, it is often difficult to pinpoint precisely when young people are ready to make important decisions. It may seem nonsensical to prohibit certain activities and not others, but taking a deeper look at the developmental science, we can see that maturity is not black and white, and distinct aspects of adulthood emerge at separate times. Thus, there is a need for different ages for different legal matters. This can help better inform how young adults and teens should be treated in the legal system and when they can be allowed to make certain decisions.