Do Life Events Change Personality? The Data Say: Barely, Briefly, If at All

New research suggests your nervous system is less vengeful than advertised.

CATEGORY: CONTROL OF LANGUAGE AND IDEAS

Peter Haehner, PhD

Source: European Journal of Personality
Read time: 1.5 minutes      
This Happened
In July 2025, a large meta-analysis addressed a question that has quietly fueled decades of clinical lore and political mythmaking: Do major life events meaningfully change adult personality?
Who Did This?
The study was led by psychologist Peter Haehner, a senior teaching assistant at the University of Zurich. Since earning his PhD in 2023, Haehner has built a research portfolio focused on personality development and change, with more than two dozen peer-reviewed publications as first or secondary author.
The Claim
The researchers pooled seven large, existing longitudinal datasets to examine whether ten common life events—both positive and negative—were associated with changes in the Big Five personality traits: Agreeableness, Conscientiousness, Emotional Stability, Extraversion, and Openness. The events included starting a romantic relationship, marriage, childbirth, separation, divorce, widowhood, graduation, new employment, unemployment, and retirement.
Across 50 statistical tests (five traits × ten events), only 12—just 24%—showed any statistically significant change. Of those, eight were increases and four were decreases. When the analysis was restricted to the authors’ a priori hypotheses, only 5 of 15 predictions were supported.
Even when effects reached statistical significance, they were trivial in magnitude. Effect sizes ranged from b = 0.00 to ±0.09—numbers so small they are functionally meaningless in real-world terms (b = 0.20 or higher is considered large in the social sciences although that still would not explain the majority of influence on an outcome).
Most importantly, the authors also examined whether changes persisted over time, assessing personality at one year, two years, and more than two years after each event. Of the 12 significant findings, only one—slightly increased emotional stability following new employment—appeared consistently across all time points. The authors were compelled to conclude that personality changes linked to life events were “mostly only temporary,” with “negligible effects more than two years after a life event occurred.” Removing the science-speak: There is no impact.
Why This Matters
These findings directly undermine the dominant mythology in contemporary trauma discourse: the claim that stress and adversity routinely “scar” the brain, permanently deform personality, or derail development. The slogan “the body keeps the score” asserts enduring damage; the doctrine of so-called “complex PTSD” claims prolonged stress reshapes personality itself. Both have been used to reframe conditions like borderline personality disorder as trauma reactions rather than largely heritable traits.
This study did not include true traumatic events—life-threatening experiences that define trauma in psychiatry. Yet these findings do not bode well for these dominant theories that extend “trauma” to encompass everyday stressors while claiming lifelong psychological deformation.