Is the Maturity Gap a Psychological Universal?
New study finds logical reasoning precedes impulse control in most countries.
Posted Mar 02, 2019
This is the second post in a two-part series. The first post examined adolescents, the maturity gap, and the law.
Last month, an international team of researchers published an impressive study that examined the so-called "maturity gap" in 11 nations. The maturity gap refers to the discrepancy between an individual's cognitive maturity and emotional maturity.
Studies by developmental psychologists over the past 25 years have identified a general principle: Different human abilities develop at different rates and reach their highest point of development at different ages.
For example, the ability to reason in a logical manner increases dramatically from childhood to age 16 or 17 and then levels off. The ability to control one's impulses, however, develops more slowly and over a longer period of time. In fact, most people aren't fully capable of emotional restraint until their mid- or late-20s.
The study published last month sought to determine if the maturity gap is a psychological universal or a culturally-variable phenomenon. In other words, can this pattern--a significant discrepancy between an adolescent's cognitive maturity and emotional maturity--be observed everywhere? Or does the phenomenon manifest itself differently or not at all in some countries and cultures?
With financial support from the Klaus J. Jacobs Foundation, psychologists Grace Icenogle and Laurence Steinberg organized a team of researchers to investigate the maturity gap in 11 nations: China, Colombia, Cyprus, India, Italy, Jordan, Kenya, Philippines, Sweden, Thailand, and the United States.
The researchers recruited more than 5,000 participants who ranged in age from 10 to 30 years. The team took special steps to ensure that each country's sample had a roughly even number of females and males and about the same number of participants in each age category. They also ensured that participants' parents had similar levels of education (some college, on average).
These methodological steps played a vital role in the study because they increased the "interpretability" of the data collected by the researchers. When national samples are made equivalent to each other in terms of key variables like gender, age, and education, researchers feel more comfortable explaining any observed patterns in terms of different cultural values and practices.
In the study, each participant completed eight separate tasks on a computer. Here are brief descriptions of five of the tasks:
- In a digit-span task, participants memorized number strings, beginning with two numbers and increasing to eight numbers. Their score was the largest number of digits recalled correctly in reverse order.
- In a verbal-fluency task, participants quickly generated as many exemplars as they could for three separate categories--fruits, vegetables, and animals.
- In a 10-item peer-resistance task, participants indicated which of two opposing statements described them best. For example, "For some people, it's pretty easy for their friends to get them to change their mind BUT for other people, it's pretty hard for their friends to get them to change their mind."
- In a sensation-seeking task, participants played a computerized driving game. At 20 different intersections, the player had to choose to either stop at a red light or run the light. Stopping at the light meant the player had to wait 3 seconds. Successfully running the light cost the player no time, but if the player's car crashed into another car, the player had to wait 6 seconds before preceding.
- In a delay-discounting task with six variations, participants had to choose between a small, immediate reward or a large, delayed reward. For example, would you rather have 200 euros today or 1,000 euros in 6 months?
According to the researchers, the first two tasks measure aspects of cognitive capacity, which is related to logical reasoning. The last three tasks measure aspects of psychosocial maturity, which is related to emotional restraint and impulse control.
Participants received a base payment ($30 in the United States). To motivate participants to perform well, they were told they would receive a 50% bonus payment if they performed at a high level on the computerized tasks. (In fact, all participants received the bonus.)
What were the results of this large multinational study? A clear pattern appeared in every country studied except Jordan: Performance on the cognitive capacity tasks increased sharply from age 10 to age 16 and then plateaued. On these tasks, the average 16-year-old performed as well as the average 30-year-old.
A second pattern appeared in 9 of the 11 countries. (Jordan and Kenya were exceptions to the rule, for reasons unknown.) Performance on the psychosocial maturity tasks increased steadily over time and didn't level off before age 30. In each country, 10-year-olds were less mature than 15-year-olds, who were less mature than 20-year-olds, who were less mature than 25-year-olds, and so on.
In sum, the maturity gap appears to be a psychological universal. Around the world, young people reach adult-levels of logical reasoning fairly quickly, usually by age 16. These same individuals, however, are not as mature as older adults when it comes to controlling their impulses, managing their emotions, and resisting peer pressure.
At the end of their article, Icenogle, Steinberg, and their colleagues offer a provocative conclusion. In legal proceedings, instead of drawing a single line that distinguishes adolescence from adulthood, it may be more sensible for the courts to establish two legal age boundaries—one for "decisions typically made with deliberation and another for decisions made in emotionally charged situations."
Icenogle, G., Steinberg, L., and 18 others. (2019). Adolescents' cognitive capacity reaches adult levels prior to their psychosocial maturity: Evidence for a "maturity gap" in a multinational, cross-sectional sample. Law and Human Behavior, 43(1), 69-85.