This article originally appeared on RealSimple.com.
If you think you’re exactly the same as your teenage self, new research may challenge that assumption. In a 63-year study, the longest ever conducted on human personality, scientists found that personalities can transform almost entirely over the course of a lifetime.
For the study, which began in 1950, psychologists at the University of Edinburgh in the United Kingdom analyzed data from more than 1,200 personality assessments given to 14-year-old students by their teachers. The educators rated their pupils on the following six personality traits: self-confidence, conscientiousness, perseverance, desire to excel, originality, and stability of moods.
Approximately 63 years later, researchers tracked down 174 of the original students, now an average of 77 years old, who agreed to take another personality test. The participants took an assessment measuring the same six characteristics that they were judged on at 14 years old. They were also asked to bring along another loved one, who then weighed in on the same traits.
The results, though published in the journal Psychology and Aging in December, are just gaining traction. And they’re quite different from what researchers expected to find: There wasn’t a whole lot of overlap between now and then—aside from a small correlation between stability of moods and conscientiousness. “The longer the interval between two assessments of personality, the weaker the relationship between the two tends to be. Our results suggest that, when the interval is increased to as much as 63 years, there is hardly any relationship at all,” the researchers wrote in the study’s conclusion. “Personality changes only gradually throughout life, but by older age it may be quite different from personality in childhood.”
It’s important to realize that the data isn’t 100 percent conclusive. The sample size of the latter study was pretty small compared to the original sample, and a teacher’s personality assessment isn’t exactly the same thing as self-assessment. Nonetheless, it is an important look into how we can change over the years—in more ways than just our appearance.