A longitudinal study examining personality changes from ages 10 to 16 found that conscientiousness and agreeableness tended to decline from ages 12 to 16. Neuroticism increased over the study period, but only among girls. The paper is Personality and Social Psychology Bulletin.
Personality is a relatively stable pattern of thinking, feeling, motivation, and behavior that makes each person unique. It influences how people perceive situations, interact with others, respond to challenges, and make decisions. Personality develops through a combination of genetic influences, childhood experiences, social relationships, culture, and life events.
One of the most widely used scientific models of personality is the Big 5 model. Openness to experience, one of the characteristics of this framework, represents curiosity, imagination, creativity, and a willingness to consider new ideas. Integrity refers to being organized, responsible, disciplined, reliable, and focused on achieving goals. Extraversion includes sociability, assertiveness, enthusiasm, energy, and a tendency to seek stimulation from others.
Agreeableness reflects kindness, cooperation, empathy, trust, and consideration for the needs of others. Neuroticism refers to the tendency to experience negative emotions such as anxiety, sadness, irritability, and emotional instability. Beneath these broad categories are narrower characteristics called facets. For example, conscience includes certain aspects of order and self-discipline, while neurosis includes anxiety and depression.
Study author Silje Steinsbekk and colleagues investigated how these global characteristics and specific aspects of them change as children grow older. They noted two opposing views about the trajectory of personality development. One view predicts that as children grow older, they become more conscientious, cooperative, and emotionally stable. An opposing idea, the disruption hypothesis, suggests that certain aspects of adolescent personality maturation temporarily decline as teenagers face new social and biological challenges.
To investigate this, the research team analyzed data from the Trondheim Early Safety Study. In 2007 and 2008, all four-year-old children born in Trondheim, Norway, along with their parents, were invited to participate in a project investigating their psychosocial development. The researchers ultimately selected just over 1,000 participants to take part in the initial evaluation.
This particular analysis focused on data collected from the time the participating children turned 10 years old. Age 10 was the age at which participants began completing self-report personality tests. In total, researchers looked at 805 children who provided data at ages 10, 12, 14, or 16. The number of children at the individual assessment points ranged from 635 to 704, with slightly more than half of the groups being girls.
The results generally supported the confusion hypothesis. Contrary to the idea of steady growth, the children’s conscientiousness and cooperativeness decreased after the age of 12. A closer look at the narrower dimensions reveals that decreased self-control causes decreased conscientiousness. Meanwhile, agreeableness decreased due to decreased compliance and altruism.
Neuroticism decreased in boys between ages 10 and 12 and remained relatively stable thereafter. In contrast, girls’ neuroticism increased from ages 12 to 16. When we look at specific aspects, we find that rising anxiety levels are driving this upward trend for girls. Extraversion also decreased between the ages of 14 and 16 for both boys and girls, but this was mainly due to a significant decline in activity.
Girls’ openness decreased over the study period. For boys, this trait decreased between ages 10 and 14 and remained relatively stable thereafter. “Our results largely support the disruption hypothesis, showing that after the age of 12, conscientiousness and agreeableness decline across genders, and increases in neuroticism are observed only in girls. Our findings further demonstrate that maturational disruption differs at the dimension level, suggesting a complex developmental process,” the study authors concluded.
This study contributes to the scientific understanding of personality development. However, all study participants were from a single city in Norway, so findings in other cultures may not be the same. Additionally, this study was based on self-reports from 10-year-old children. Younger children are generally less reliable in reporting their own behavior, which may have affected the accuracy of the initial assessment.
The paper “Personality from 10 to 16 years of age. A four-wave cohort study of development and sex differences in the Big Five and their dimensions” was authored by Silje Steinsbekk, Lars Wichstrom, and Tilmann von Soest.
