Is personality really set in stone after early adulthood? For years, many researchers believed that core traits become increasingly stable after age 30. A new longitudinal study published in Communications Psychology challenges that assumption, reporting that both younger and older adults showed measurable changes in emotional stability and extraversion following a structured socio-emotional intervention.Personality Plasticity: Study Shows Similar Changes in Young and Older Adults. Image by FreepikNote: This article is intended for general information and educational purposes. It summarizes scientific research in accessible language for a broad audience and is not an official scientific press release.A new peer-reviewed study published in Communications Psychology at the end of last year examined whether personality traits such as emotional stability and extraversion can change through structured training – and whether age influences this process.The research was conducted by Gabriela Küchler, Kira S. A. Borgdorf, Corina Aguilar-Raab, Wiebke Bleidorn, Jenny Wagner, and Cornelia Wrzus. The authors are affiliated with Heidelberg University, the University of Mannheim, the University Hospital Heidelberg, the University of Zurich, the University of Hamburg, and the Network for Aging Research.According to the researchers, the eight-week in-person intervention resulted in increases in emotional stability and extraversion. Importantly, these effects were consistent across younger and older adults.What the Researchers InvestigatedThe researchers addressed two central questions.First, they examined whether short-term changes in personality “states”, such as how calm, stressed, outgoing, or reserved participants felt during a given week, were associated with changes in more stable personality self-concepts.Second, they tested whether these processes differed between younger and older adults.Previous research has suggested that personality development becomes less pronounced after young adulthood. However, intervention studies have rarely examined age differences directly, and most relied solely on self-report questionnaires. This study expanded that approach by including both explicit (self-reported) and implicit (reaction-time based) measures of personality.The final sample consisted of 165 participants aged 19 to 78 years. It included 80 younger adults (mean age 28.33 years) and 85 older adults (mean age 63.55 years). The study was preregistered and used a multi-method design.How the Study Was ConductedParticipants completed an eight-week in-person socio-emotional intervention delivered in weekly two-hour group sessions.The intervention had two phases:• Weeks 1–4 focused on emotional stability, including stress management, attention regulation, and emotion regulation strategies.• Weeks 5–8 focused on extraversion and interpersonal competencies, including social behavior, communication, and boundary-setting skills.Participants were assigned to small groups and completed daily exercises between sessions. They selected a “training buddy” and engaged in structured reflection and behavioral practice tasks.Personality traits were assessed at five time points:• Before the intervention (T1)• Four weeks into the intervention (T2)• Immediately after the intervention (T3)• Three months after completion (T4)• Twelve months after completion (T5)Explicit personality self-concepts were measured using the Big Five Inventory-2. Implicit self-concepts were measured using the Implicit Association Test (IAT), which assesses automatic associations between the self and specific trait characteristics. Weekly personality “states” were measured throughout the eight weeks to track short-term changes in emotional stability and extraversion.What Makes This Study DifferentThe authors highlight three key contributions:The study examined changes beyond self-report questionnaires by including implicit measures of personality.It directly tested whether weekly state changes predicted longer-term trait changes.It systematically compared younger and older adults within the same structured intervention.According to the authors, the findings emphasize that older adults might benefit as much from socio-emotional interventions as younger adults.Key Findings from the StudyThe results showed consistent and measurable changes during the eight-week intervention. Below are the main findings presented in clear terms.Emotional stability increased during the program. Participants reported feeling calmer and better able to handle stress from week to week. These short-term improvements were statistically reliable across the intervention period.Extraversion also increased during the program. Participants reported being more outgoing, socially active, and expressive over the course of the eight weeks.Self-perceptions of personality changed. When asked to describe themselves in general terms, participants reported higher levels of emotional stability and extraversion by the end of the intervention. In addition, automatic associations related to extraversion, measured using a reaction-time task, also increased. However, automatic associations related to emotional stability did not show consistent change.Changes in weekly emotional experiences were linked to changes in self-concept. Participants who showed stronger week-to-week increases in emotional stability were more likely to report lasting increases in how emotionally stable they saw themselves. This pattern was observed for emotional stability but not clearly for extraversion.Age did not limit personality change. Younger and older adults showed similar patterns of change. Age did not significantly influence improvements in emotional stability or extraversion.It also did not meaningfully affect how short-term changes were connected to longer-term personality self-concepts. Some changes were maintained over time. At follow-up assessments three and twelve months later, self-reported emotional stability remained stable. Self-reported extraversion showed a small decline after the program ended, though levels remained above baseline. Implicit measures showed no consistent long-term changes, except for a continued increase in automatic extraversion associations among older adults.Overall, the findings indicate that structured socio-emotional training was associated with measurable changes in emotional stability and extraversion, and these changes occurred similarly across age groups.Engagement and AgeExploratory analyses showed that older adults reported higher engagement with the intervention compared to younger adults. They were more actively involved in completing weekly tasks and using the audio-based practice materials throughout the eight-week program.Younger adults, in contrast, reported experiencing more hectic and more atypical weeks during the intervention period. There were no age differences in reported weekly exhaustion.At baseline, younger participants expressed a stronger desire to improve their level of extraversion. However, age did not moderate changes in extraversion during the intervention. Both younger and older adults demonstrated increases in extraversion over the course of the program, with no meaningful age-related differences in the pattern of change.As summarized by NeuroscienceNews, this study answered the following questions:Q: I thought personality was permanent by age 30?A: That used to be the scientific consensus, but this study shows that the “socio-emotional” parts of our personality – how we handle stress and talk to others – remain surprisingly flexible well into our 80s.Q: Why was the older group more successful than expected?A: Motivation and “homework.” While learning a new language might get harder with age, the older participants in this study were more likely to actually do the practice assignments and take the emotional training seriously, which leveled the playing field with the younger group.Q: Can I change my personality on my own?A: This study used a specific 8-week structured course. However, the takeaway is that with the right motivation and social skills training, anyone can become more emotionally stable or outgoing, regardless of their birth year.Authors’ ConclusionsThe authors conclude that the eight-week socio-emotional intervention was associated with increases in emotional stability and extraversion in both younger and older adults.They state that the findings advance personality theory by demonstrating:Changes beyond trait self-reports, through the inclusion of implicit measures.The role of weekly personality states as underlying processes contributing to trait change.Age similarities in personality development within a structured intervention context.The authors also discuss the possibility that smaller normative personality changes often observed in older adulthood may reflect differences in contextual triggers, motivational dynamics, or developmental processes rather than a reduced capacity for change. They frame this as a theoretical consideration that requires further research.Finally, they acknowledge several limitations, including the need for more fine-grained assessments of personality states over time and additional studies to clarify which specific components of the intervention are most responsible for observed changes.ConclusionFor decades, personality was often described as largely stable after early adulthood. This study contributes new data to that discussion. Within a structured eight-week socio-emotional program, measurable shifts in emotional stability and extraversion were observed in adults ranging from their twenties to their seventies.Importantly, age did not meaningfully moderate these changes. The findings suggest that, under controlled intervention conditions, personality-related processes linked to emotional regulation and social behavior can show measurable movement across different stages of adulthood.At the same time, the authors emphasize that questions remain about long-term mechanisms, contextual influences, and which elements of the intervention drive change. Further research will be needed to clarify how personality development unfolds beyond structured training environments.The information in this article is provided for informational purposes only and is not medical advice. For medical advice, please consult your doctor.ReferencesKüchler, G., Borgdorf, K.S.A., Aguilar-Raab, C. et al. Personality intervention affects emotional stability and extraversion similarly in older and younger adults. Commun Psychol 3, 171 (2025). https://doi.org/10.1038/s44271-025-00350-2NeuroscienceNews. “Brain Never Outgrows the Ability to Emotionally Evolve.” NeuroscienceNews, https://neurosciencenews.com/personality-psychology-aging-growth-30136/The post Is Personality Fixed After 30? New Research Says Otherwise appeared first on CogniFit Blog: Brain Health News.