Crawls performed by Internet Archive on behalf of the National Library of Australia. This data is currently not publicly accessible. ||||| Most psychologists agree that a person's basic personality—whether they are an introvert or extrovert, for example—remains the same throughout life. What we might see as personality changes are actually just responses to external factors, such as getting a job, getting married or becoming a parent. That said, research does indicate that our personalities become more solidified, or stable, as we get older. 
 
 That change is not linear, however. New research indicates that our personalities become increasingly stable as our 20s melt into our 30s, 40s and even 50s, but that that stability then often begins to taper off in old age, Research Digest reports. 
 
 Researchers in New Zealand recruited 4,000 men and women aged 20 to 80 to complete a personality questionnaire twice, with a gap of two years in between. The survey measured a person's honesty-humility factor as well as five major personality traits: extraversion, agreeableness, conscientiousness, neuroticism and openness to experience, Research Digest writes. They compared how people's scores varied between years, and analyzed how all of the participants personalities related to one another, depending on age. 
 
 Most people's personalities were generally stable, they found, but the stability of those trait followed a bell curve over time, peaking at middle-age and then dropping again. For certain traits—conscientiousness, openness to experience, and honesty-humility—Research Digest writes, the oldest participants' personality stability matched those of the youngest. 
 
 Other interesting finds included "domain specific" variations, or ones that seem to be linked to what a person is dealing with at a particular point in their life. People in their 30s, for example, showed high levels of neuroticism, but by the time they reached their 50s that had tapered off and had been replaced by conscientiousness, openness and honesty-humility.
– There's no doubt about it: The human body goes through major changes in youth and old age. And these biological and social changes may be the reasons behind what researchers are calling less stable personalities at those life stages. In fact, according to a study of almost 4,000 New Zealanders between the ages of 20 and 80, the stability of one's personality increases through youth and into middle age and peaks in our 50s, before we slide back into less stable versions of ourselves, reports Research Digest. As the Smithsonian puts it, "in some ways, our 80-year-old selves mirror our 20-year-old selves." Some traits peaked at different times; the most stable traits in one's 30s are extraversion and neuroticism, while in the late 40s and early 50s it is openness, honesty-humility, and conscientiousness. The only trait that showed "gradually reduced stability" throughout life was agreeableness; apparently we are simply less and less agreeable as we pack the years on. Still, one's most basic personality—introvert vs. extrovert, for example—tends to remain consistent throughout one's life, even if the stability of traits waxes and wanes, notes the Smithsonian. (Other researchers have even calculated the country's most extroverted city.)