Infants exhibiting behavioral inhibition can be predicted to grow up to be adults with a reserved, introverted personality at age 26. In addition, if these individuals, during adolescence, show higher sensitivity to making errors, they will be at higher risk to develop internalizing disorders such as anxiety and depression in adulthood. The findings were made by researchers at National Institutes of Health and published in the journal Proceedings of the National Academy of Sciences.
Foundation of Later Personality
Past studies have linked early childhood behavior to risk for psychopathology. This study is unique because it follows the participants from infancy until the age of 26.
A baby’s temperament can serve as a foundation of later personality. A temperament observed in infants called behavioral inhibition is characterized by cautious, fearful, and avoidant behavior toward unfamiliar people, objects, and situations. Behavioral inhibition is found to stay with the individual through childhood. As they grow into adulthood, these individuals are at greater risk for developing social withdrawal and anxiety disorders than children without behavioral inhibition.
In this study, the researchers recruited infants at 4 months of age and screened them to see if they had behavioral inhibition at the age of 14 months. The participants returned when they were 15 years old to be measured for what is called error-related negativity. The participants performed computerized tasks, and when they made an error, a negative dip in the electrical signal recorded from the brain is shown. This is called error-related negativity. A larger error-related negativity signal has been associated with internalizing conditions such as anxiety, and a smaller error-related negativity has been associated with externalizing conditions such as impulsivity and substance use.
Came Back at 26 Years Old
The participants came back again when they reached 26 years old. They were then accessed for psychopathology, personality, social functioning, and education and employment outcomes. In all, the participants were part of the study from 4 months old until they were adults 26 years old.
“It is amazing that we have been able to keep in touch with this group of people over so many years. First their parents, and now they, continue to be interested and involved in the work,” said study author Nathan Fox.
Behavioral Inhibition Linked With Lower Social Functioning
The results showed that infants accessed with behavioral inhibition at 14 months old had a more reserved personality, fewer romantic relationships in the past 10 years, and lower social functioning with friends and family when they became adults at 26 years old. However, only those with larger error-related negativity signals at age 15 displayed higher levels of internalizing psychopathology in adulthood. There was also no association between behavioral inhibition and externalizing general psychopathology or with education and employment outcomes.
Screening for Psychopathology in Adulthood
In short, this study supports the notion that an infant’s temperament usually forms the foundation of adulthood personality. Especially noteworthy is that individuals who showed behavioral inhibition as infants and who also later displayed larger error-related negativity signals at age 15, showed higher risk of developing of internalizing psychopathology. They would thus be prone to anxiety and depression in adulthood. As more studies like this add to our knowledgebase, we might be able to accurately screen infants for psychopathology in adulthood.