Many of us look back at old photographs and realize our fashion sense, hairdos, and overall physical appearance has changed from childhood to adulthood. We may find that traces of our personality quirks linger, but whether we're the same person throughout a lifetime is up for debate. Researchers at the University of Edinburgh in Scotland suggest our personality traits do not remain constant from our teenage years to old age, and bear no resemblance to our personalities in mid-adolescence.

“The longer the interval between two assessments of personality, the weaker the relationship between the two tends to be,” wrote study author Matthew Harris and his colleagues.

They added: “Our results suggest that, when the interval is increased to as much as 63 years, there is hardly any relationship at all.”

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This is the first sign that our cells are not the only things being constantly replaced; the way we think, behave, and speak also gradually changes with age. Previous research has found personality consistency in shorter periods of time, where researchers focus on participants from childhood to middle age, or from middle age to older age. However, over a longer period, it seems personality stability is disrupted over time.

In 1950, when the longest personality study took place, a group of researchers asked teachers to rate the personality of over 1,200 14-year-olds in Scotland. The teachers rated the teens on six traits: self-confidence, perseverance, stability of moods, conscientiousness, originality, and desire to excel. These results were then used to calculate an overall rating for a single underlying trait, known as "denoted dependability," a trait similar to conscientiousness.

Six decades later, Harris and his colleagues recruited over 630 teenagers who were assessed back in 1950. A total of 174 participants, now aged 77, agreed to take part in a new round of testing. The group, including 92 women, rated themselves on the same six items that their teachers had rated them on back in 1950. They also nominated a close friend or relative to rate them on the items too. The participants completed some intelligence tests and measures of their general wellbeing. The results were once again condensed into a single "dependability" score.

Surprisingly, when the researchers compared the results at 77 years to those at 14 years, there was no notable correlation. No statistical significance was found between the ratings of the participants when they were aged 14 and the ratings they gave themselves at age 77, or the ratings their friend or relative game them. Dependability correlated with current wellbeing, but the participants' dependability at age 14 was not linked with their wellbeing in late life.

"We hypothesized that we would find evidence of personality stability over an even longer period of 63 years, but our correlations did not support this hypothesis,” they wrote.

It seems people change quite a bit from their 14-year-old selves. However, the study does present some caveats; the sample size was very small and not diverse. The original study did not allow the participants to rate themselves, so the results were solely reliant on their teacher's assessment of them. In addition, self-reporting can be faulty, because it could be influenced by bias, either by the teacher towards the student at 14, or the friend or family member at 77.

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More importantly, the researchers only focused on links between personality results, and not at circumstances that could influence changes in personality traits throughout life. Inevitably, further research is needed to explore why our personalities do not remain constant in old age.

A similar 2014 study of more than 23,000 people in Germany found the personality of older people can change similarly as that in young adults. The researchers found up to 25 percent of the participants experienced a dramatic personality change after the age of 70. Surprisingly, they noted health changes, grandparenthood, and retirement played only small roles in personality differences.

Psychologists wonder whether changes in everyday lives of senior citizens, or whether a changed attitude toward life is responsible for these personality changes.

Personality changes may be an effect of aging. For those who had a terrible personality in their youth, a new personality may be a much welcome and needed change.

Source: Harris MA, Brett CE, Johnson W et al. Personality Stability From Age 14 to Age 77 Years. Psychology and Aging. 2016.

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