How people interpret life milestones is tied to how their personalities develop

Major life events can shape personality, but their effects depend heavily on who experiences them and how they interpret them. This is the conclusion of a new study published in the Journal of Personality. The research found that factors such as age, gender, personal perceptions, and even who was assessing the personality influenced whether events were linked to lasting changes.

While personality traits are often viewed as relatively stable characteristics, research has increasingly shown that people can change over time. Events such as entering a relationship, becoming a parent, experiencing illness, or changing jobs have all been proposed as potential triggers for personality development. Yet studies examining these links have often produced conflicting findings, prompting researchers to examine individual differences in greater detail.

Lara Oeltjen from the University of Bremen and Christian Kandler from Bielefeld University analyzed data from 623 participants who completed three assessments over a four-year period. In addition to self-reports, up to three informants rated each participant’s personality. The researchers examined 21 categories of life events spanning work, finances, relationships, housing, health, and personal achievements.

Utilizing a new modeling approach, they found that life events were associated with changes in several personality traits, but the patterns varied considerably depending on the type of event. Social and personal events showed the largest number of associations with personality change, whereas housing-related events tended to have weaker effects.

Relationship events appeared particularly influential, though sometimes in unexpected ways. Entering a new relationship was linked to decreases in conscientiousness in some analyses, while relationship dissolution was associated with decreases in agreeableness. The birth of a child was associated with a decrease in openness, whereas setbacks and adverse experiences showed more mixed effects.

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The study also found that age mattered. Older participants generally showed stronger personality changes following certain life events than younger adults. Gender differences emerged as well, with some events producing personality shifts among women but not men, and vice versa. For example, women experienced a steeper decrease in trait variance following a gain-based occupational event.

In addition, people’s subjective interpretations of events played an important role. Individuals who viewed an event as more positive often showed different personality trajectories than those who viewed the same event negatively. For instance, experiencing a change in the domestic situation caused a decrease in emotionality when the event was viewed positively.

One of the most striking findings was the inconsistency between measurement methods. Some life-event effects appeared only when participants rated their own personalities, while others were visible only in ratings provided by friends, family members, or partners. This suggests that personality changes following major life experiences may be noticeable from some perspectives but not others.

Oeltjen and Kandler concluded that “this high volatility of life-event effects might serve as an explanation for the inconclusive state of research on this topic, as studies differing in one or more of these factors are unlikely to produce similar results.”

The study also identified several important limitations. Life events were assessed retrospectively, meaning participants had to recall experiences that occurred over the previous two years. The researchers also did not collect precise information about exactly when the events occurred during the observation windows.

The study, “Individual Differences in the Effects of Life Events on Personality Trait Change,” was authored by Lara Oeltjen and Christian Kandler. It was published in 2026.