Personality development refers to systematic continuity and change in a person's characteristic patterns of thinking, feeling, motivation, self-regulation, and behavior across time. It begins with early differences in temperament and develops through repeated interactions among biological dispositions, relationships, chosen activities, social institutions, and historical circumstances. Decades of longitudinal research establish two complementary findings: people become increasingly recognizable in their relative patterns, particularly from childhood into early adulthood, while their average trait levels and individual trajectories continue to change. Personality development therefore requires studying who remains relatively similar, which characteristics shift, when shifts occur, and what processes sustain them. Bleidorn et al., 2022; Costa et al., 2019.
A lifespan account examines development from infancy and childhood to adolescence, emerging adulthood, midlife, and old age. It treats personality as a dynamic system with enduring dispositions and changing ways of expressing them. Although much of the quantitative literature uses Big Five measures, the developmental questions addressed here extend across trait models, temperament research, motivation, self-concept, and longitudinal methods. The specialized measurement, predictions, and comparisons of OCEAN dimensions belong to the Big Five scientific articles; this chapter synthesizes developmental continuity and change across personality science. Roberts and DelVecchio, 2000; Haehner et al., 2026b.
The Scientific Meaning of Personality Development
Personality, temperament, traits, and states
A personality trait is a relatively persistent tendency in patterns of feeling, thinking, and behavior. A trait is probabilistic: it describes what is characteristic across repeated occasions rather than what a person must do in one situation. A personality state is a particular moment's expression, influenced by fatigue, demands, company, incentives, expectations, and the individual's current goals. A person can have a generally sociable disposition while seeking solitude during an exhausting week. Stable traits are inferred from patterns across such states and contexts. This distinction matters because a temporary reaction, a lasting shift in a disposition, and an altered self-description are different phenomena. Costa et al., 2019.
Temperament denotes comparatively early-emerging differences in emotional and behavioral reactivity, activity, attention, and regulation. It provides developmental precursors to aspects of later personality, but later personality also includes learned beliefs, goals, identities, habits, and forms of self-regulation cultivated in social relationships. Temperament assessments in infancy are therefore neither abbreviated adult personality questionnaires nor forecasts of fixed adult identities. Evidence linking observed childhood behavioral styles with later adult traits supports developmental connections, while leaving considerable room for individual divergence. Caspi et al., 2003.
Continuity does not mean immobility
Continuity can refer to preservation of a recognizable personal style, persistence of a person's relative rank among peers, or maintenance of a configuration of attributes. Change can refer to growth in average scores, movement of an individual away from an earlier trajectory, alteration in variability, or transformation in the processes that generate the same outward behavior. An adult may remain more reserved than most colleagues and become substantially more outgoing than they were at 18. Both observations can be correct because they use different comparisons. This distinction is foundational to interpreting the lifespan literature. Bleidorn et al., 2022.
A related distinction separates development from simple aging. Development is a process observed within people over time. Age differences obtained from a one-time survey combine aging, birth-cohort influences, selective participation, historical opportunities, and measurement variation. A 70-year-old cohort and a 25-year-old cohort may differ because they lived through different economies, educational systems, family structures, and technologies. A strong theory of lifespan development requires temporal evidence and an explicit account of context. Costa et al., 2019.
Four Ways Personality Can Remain Stable or Change
Rank-order stability: continuity relative to other people
Rank-order stability asks whether individuals who score relatively high on a characteristic at one assessment still tend to rank high compared with peers later. Researchers often represent it with a correlation between two assessments in the same cohort. A high correlation indicates substantial preservation of relative differences across people. It does not mean that scores remained identical, or that everyone changed by exactly the same amount. A historical meta-analysis by Roberts and DelVecchio combined 152 longitudinal studies and found progressively stronger rank-order consistency from childhood to adulthood. Estimates depended on age and interval length, so a correlation should never be interpreted without specifying the design. Roberts and DelVecchio, 2000.
A larger 2022 synthesis updated these estimates using longitudinal studies published after January 1, 2005: 189 samples involving 178,503 participants contributed rank-order information, and 276 samples with 242,542 participants contributed mean-level information. Relative stability increased through early life and reached a plateau by young adulthood; the authors found little evidence for continued systematic increases after approximately age 25. This finding updates the older claim that rank-order stability rises steadily well into late middle adulthood. Both syntheses support increasing early continuity, while their different age trajectories warn against treating one meta-analytic curve as timeless. Bleidorn et al., 2022.
Mean-level change: how the average person changes
Mean-level change concerns the average score of a population or cohort across assessment waves. Imagine that every member of a cohort becomes somewhat more self-disciplined over a decade while their order relative to one another stays nearly unchanged. Mean levels changed even though rank-order stability remained high. Conversely, a stable mean can hide substantial increases for some individuals and decreases for others. The scientific interpretation therefore requires both indices rather than one number said to capture personality stability. Roberts et al., 2006.
The influential 2006 meta-analysis, based on 92 samples, reported typical increases in social dominance, conscientiousness, and emotional stability, especially between ages 20 and 40. It also identified age-related differences among facets of extraversion and openness, and meaningful change into later life. The updated 2022 synthesis broadly corroborated a maturity-associated pattern but estimated somewhat smaller cumulative shifts and more consistently increasing emotional stability. Mean-level trends are population summaries, sensitive to instruments, generations, starting ages, and time spans; they are not age-based predictions for a particular person. Roberts et al., 2006; Bleidorn et al., 2022.
Individual differences in change: distinct pathways
A cohort's average trajectory may not represent any particular participant's path. Individuals differ in the onset, direction, duration, and magnitude of change. Some exhibit gradual shifts; others change around enduring alterations in relationships or work; some maintain remarkable consistency through major transitions. Quantifying this heterogeneity is distinct from estimating the average effect of age. Longitudinal data with multiple waves are especially valuable because two observations can miss reversals, short-term fluctuations, and nonlinear trends. Graham et al., 2020.
A 2026 meta-analysis of 229 longitudinal studies comprising 230,492 participants demonstrated significant differences between individuals in developmental change for every examined trait. Heterogeneity was most pronounced during childhood, diminished into young adulthood, and remained detectable across the lifespan. The authors also reported differences by trait, observation interval, and measurement level. The established conclusion is that personal developmental paths vary; identifying the exact cause of any one person's change remains a substantially harder causal question. Haehner et al., 2026b.
Variance: whether people become more alike or different
A fourth developmental question asks whether the spread of scores across a population increases or decreases. A change in variance is neither a change in the average nor necessarily a change in individual rank. Stable variance can coexist with substantial shifts in mean levels, while stable means can coexist with increasing dispersion. A 2026 synthesis of 362 longitudinal studies encompassing 398,124 participants found broad stability in population-level trait variance over age, alongside more specific departures, including increased neuroticism variance in late childhood and early adolescence and reduced extraversion variance over parts of adulthood. Effect sizes also varied between studies and measures. The result refines assumptions that aging necessarily makes personalities uniformly more similar or more different. Haehner et al., 2026a.
Early Childhood: The Developmental Roots of Personality
Early individual differences are expressed through patterns of approach and withdrawal, positive and negative emotional reactivity, motor activity, attention, and regulation. Their observed meaning changes with developmental capacity. A toddler's difficulty waiting may involve immature executive control and situational overload; an adolescent's tendency to plan or persist is assessed under more complex social expectations. Comparing them demands age-appropriate constructs and instruments rather than treating identical labels as proof of identical mechanisms. Broad continuity may coexist with changes in the behavioral manifestations of the underlying characteristic. Caspi et al., 2003.
The Dunedin longitudinal cohort provides a particularly instructive example. Caspi and colleagues observed approximately 1,000 children at age three and examined their adult personalities at 26 using multiple assessment methods, including self-reports and informant ratings. Early behavioral profiles were associated with characteristic adult functioning more than two decades later. This supports a developmental relationship between early behavioral styles and adult patterns, while the group associations cannot determine the future of any individual child. The study also illustrates why combining observation with later self-report is stronger than using a single caregiver adjective as an adult prediction. Caspi et al., 2003.
Developmental continuity emerges through accumulating exchanges with caregivers, peers, teachers, routines, institutions, and opportunities. A temperamentally cautious child may be supported into confident exploration, placed under pressure that reinforces avoidance, or show different behavior across classrooms and home. Family conditions matter, but simple one-directional stories about parenting miss the child's role in shaping interactions and the wider social context. Longitudinal associations between early style and adult personality establish patterned development, not a single immutable pathway. Caspi et al., 2003; Roberts et al., 2005.
Early assessment and the problem of changing measures
Children's personality is often rated by parents or teachers, whereas adults more often complete self-report inventories. A difference between childhood and adult estimates can arise partly because the same trait is expressed differently or because reporters see different situations. Cross-age measurement requires establishing what is comparable and documenting how instruments translate developmental manifestations into scores. A child's effortful control and an adult's conscientious planning have conceptual links, but the procedures used to measure them and the contexts in which they are expressed are different. Scientific reviews identify measurement error and self-informant differences as ongoing reasons for conflicting developmental conclusions. Costa et al., 2019.
Adolescence: Reorganization, Roles, and Emerging Identity
Adolescence combines biological maturation with expanding social autonomy, academic demands, peer networks, and changes in identity. The period is especially informative because it reveals how growing self-regulation and social expectations interact with inherited and early-emerging tendencies. Young people do not progress along one uniform personality path. Trajectories can involve growing confidence, increased emotional variability, stronger persistence, or temporary challenges to regulation depending on the specific characteristic and developmental setting. Group averages must be interpreted against heterogeneity within the same cohort. Bleidorn et al., 2022; Haehner et al., 2026b.
Repeated observations across adolescence can distinguish change within a young person from differences between age groups. A nine-year Dutch study following two cohorts from adolescence toward young adulthood examined personality maturation alongside leaving home, first employment, first romantic involvement, and cohabitation or marriage. Its design demonstrates the value of studying transitions and development jointly: an individual's dispositions may influence which transitions occur and when, while experiences connected with transitions may also shape later dispositions. A statistical link between an event and a change does not by itself establish the direction of causation. Van Dijk et al., 2020.
Adolescence also exposes the danger of treating temporary distress or social conflict as a lasting personality deficiency. Time-specific experiences, developmental demands, family and peer circumstances, and individual coping capacities all affect what an assessment captures. Personality traits describe normative variation; psychological symptoms and disorders require separate clinical criteria. Research comparing longitudinal personality and internalizing symptoms in adolescents has found distinguishable patterns of stability, reinforcing the need to avoid collapsing developmental traits and symptom states into a single label. Costa et al., 2019.
Emerging and Early Adulthood: Maturation and Social Investment
During emerging adulthood many people acquire sustained responsibilities in work, education, households, and close relationships. Major longitudinal syntheses document average maturation-associated movement in characteristics related to self-control, responsibility, interpersonal functioning, and emotional regulation. Some of these patterns are strongest between roughly ages 20 and 40, though effects vary by trait and cohort. The common phrase personality maturity describes a statistical tendency, not a moral hierarchy or the assumption that anyone with a different trajectory is immature. Roberts et al., 2006; Bleidorn et al., 2022.
The social investment perspective explains part of maturation through ongoing commitment to social roles. Roles create repeated expectations, routines, feedback, constraints, and opportunities to practice behaviors. Someone who undertakes work requiring reliable coordination may gradually build habits of preparation and follow-through. A close relationship may generate opportunities to manage conflict and respond to others' needs. Over time, such repeated patterns may feed back into self-concept and typical behavior. The perspective is a developmental explanatory model supported by some observational evidence; it is not a verified rule that taking a job, marrying, or becoming a parent automatically improves personality. Roberts et al., 2005.
A large cross-cultural investigation of young adulthood analyzed data from 884,328 respondents in 62 nations. It found broad age-related maturation patterns with meaningful cultural variation; in settings where adult-role responsibilities typically began earlier, maturation-related age trends also tended to appear earlier. Because that study's comparisons were largely cross-sectional and Internet-based, the results establish cross-cultural associations rather than a causal experiment on role timing. The study nonetheless demonstrates why social schedules and historical conditions must enter any explanation of supposedly universal developmental ages. Bleidorn et al., 2013.
Midlife: Continuity Through Accumulating Experience
Middle adulthood often combines established habits with occupational changes, relationships, caregiving demands, health experiences, and evolving goals. By this period many relative personality differences are already moderately to highly stable, yet stability does not eliminate development. Some adults become more organized, cooperative, or emotionally regulated; others show divergent trends. The 2022 meta-analysis challenges the claim that relative stability must continue increasing indefinitely throughout middle adulthood, while confirming that average change is still measurable. In other words, a person can retain a distinctive profile as their everyday behavior evolves. Bleidorn et al., 2022.
Studies that pool cohorts can conceal nonlinear paths. In a coordinated analysis of 16 longitudinal samples involving more than 60,000 participants, Graham and colleagues reported heterogeneous developmental trajectories, including average decreases in conscientiousness, extraversion, and openness in some models, with indications of late-life increases in neuroticism in nonlinear analyses. Differences between countries, samples, ages, and instruments partly explained heterogeneity. Such findings caution against extending an early-adulthood maturation trajectory into every later decade as though social and biological conditions remained unchanged. Graham et al., 2020.
Later Adulthood and Aging
Late adulthood presents opportunities for psychological adaptation along with changes in health, mobility, social networks, responsibilities, and perceived time horizons. Several synthesized findings point toward later-life declines in average levels of characteristics such as extraversion, openness, or conscientiousness, while emotional stability can show a different course. Researchers continue to debate the relative contributions of age-related demands, self-regulation, selective activities, cohort characteristics, and measurement. A motivational framework proposes that altered opportunities for controlling the environment and adaptation to losses may help explain some trends; the framework is an explanatory hypothesis, not a direct demonstration of causal mechanisms. Bleidorn and Hopwood, 2024.
Patterns of aging should be interpreted with special attention to selection and survival. Older adults able and willing to participate in long studies may differ from peers who have dropped out. Changing health may alter how a questionnaire item functions; for example, low activity can reflect physical limitations as well as temperament. Cross-sectional comparisons can conflate chronological age with historical generation. A careful interpretation asks whether an observed score difference signals a true personality shift, a different behavioral opportunity, a change in measurement meaning, or several of these together. Costa et al., 2019; Graham et al., 2020.
An individual's older age remains a period of variation. The 2026 meta-analysis of change heterogeneity found differences between people across the entire lifespan, even though their magnitude was generally smaller than in childhood. Population-level variance also remained broadly stable in a separate synthesis. Taken together, these findings support attending to individual goals, relationships, resources, and constraints rather than projecting one average aging curve onto every older adult. Haehner et al., 2026b; Haehner et al., 2026a.
Why Personality Develops: Biological and Environmental Processes
Genetic contributions and developmental plasticity
Behavioral-genetic research consistently indicates that genetic differences contribute to variation in personality. A 2015 meta-analysis of genetically informative studies synthesized evidence involving more than 100,000 participants and evaluated differences across designs and measures. Heritability refers to the proportion of variation in a measured characteristic statistically associated with genetic differences in a particular population and environment. It is a population estimate, not a percentage of one person's character, and it does not specify how changeable that person's behavior is. Vukasović and Bratko, 2015.
Genetic contributions can operate through multiple biological and behavioral pathways and can become expressed differently as experiences, responsibilities, and developmental capacities change. The same genetic predispositions may relate to different behaviors at different ages. Gene-environment correlations arise when a person's characteristics are associated with the environments they experience, partly through seeking, evoking, or receiving particular contexts. Evidence for heritability therefore belongs alongside evidence of plasticity, intervention effects, and social transactions. Neither a single gene nor a single neurotransmitter provides a valid comprehensive explanation of a complex personality trajectory. Vukasović and Bratko, 2015; Roberts et al., 2005.
Repeated situations, habits, and person-environment transactions
Person-environment transactions describe reciprocal links between enduring tendencies and the environments people encounter. People tend to select activities and relationships partly on the basis of preferences, responses from other people may reinforce or modify behavioral patterns, and environments can reward habits that gradually become more automatic. A disposition thus participates in shaping its own developmental context. These processes offer plausible explanations for accumulating stability and change, although isolating each pathway empirically requires designs that distinguish selection from exposure and ongoing feedback. Roberts et al., 2005; Costa et al., 2019.
Repeated behavior is a potential bridge between momentary states and longer-term traits. New social roles may alter what someone practices daily; daily practice can change confidence, regulatory skills, self-expectations, and eventually trait assessments. Yet causal sequences can be circular. The person who takes on a demanding organizational role may already be unusually conscientious. A suitable research design measures traits before and after exposure, includes comparable people without the exposure when feasible, and examines whether the putative mediating behaviors actually changed. Bühler et al., 2024.
Life events and transitions: small, specific associations
Life events can transform opportunities, routines, relationships, resources, and stress. A preregistered 2024 meta-analysis combined 44 studies, 89 samples, and 121,187 participants to examine personality change associated with events in work and close relationships. It found generally small, event-specific effects, with more consistent associations in work-related transitions than relationship-related transitions. Graduation, first employment, new relationships, marriage, and divorce appeared among events associated with the strongest changes in the synthesis, but even statistically reliable associations were generally modest. These results support contextual contributions while limiting stories in which one major event predictably reconstructs personality. Bühler et al., 2024.
Events also differ in meaning. A job transition experienced as opportunity has different psychological consequences from one experienced as coercion or loss; marriage varies in relational quality and circumstances; unemployment differs according to material security and support. Timing matters, as does how a person anticipates an event and behaves afterward. Longitudinal observational studies have improved the field, but confounding, reciprocal selection, and short follow-up periods remain significant constraints on causal interpretation. Bühler et al., 2024.
Can People Deliberately Change Personality?
Intentional change is scientifically plausible, and intervention studies provide more direct evidence than age comparisons alone. A 2017 systematic review and meta-analysis identified 207 intervention studies measuring personality characteristics over time. It reported average shifts in measured traits over a period of roughly 24 weeks, with particularly substantial evidence involving emotional stability and extraversion. The reviewed interventions were varied, and many took place in clinical settings; their results cannot be read as proof that any particular self-help technique will reproduce the average. Study design, comparison conditions, symptom improvement, and follow-up duration affect what the findings establish. Roberts et al., 2017.
A randomized trial published in 2021 tested a three-month smartphone-supported program for desired trait change with 1,523 participants. Participants receiving the intervention reported greater change in intended directions than a waitlist comparison group; acquaintances also detected some changes, though their effects were smaller and not uniformly significant. Effects observed for a period after the intervention support the possibility of lasting changes, while short follow-up windows, participant motivation, and potential reporting effects limit conclusions about permanent transformation or effectiveness in other populations. Stieger et al., 2021.
The distinction between changing a trait score and changing a characteristic style of functioning remains crucial. Self-reported progress may reflect growing insight, changed standards of self-evaluation, or a genuine shift in habitual behavior. A rigorous evaluation combines self-reports with informant impressions, behavioral observations, repeated measurement, suitable controls, and evidence of functional relevance. In practice, achievable goals often concern specific behaviors and environments: creating routines, practicing social interaction, regulating reactions, or choosing contexts that support desired habits. Such goals can be meaningful even when a broad inventory changes only modestly. Stieger et al., 2021; Costa et al., 2019.
Studying Personality Development Scientifically
Longitudinal cohorts and repeated assessments
A longitudinal design follows the same people across multiple time points, making it possible to estimate individual changes and correlations among their relative standings. Studies with three or more assessments are especially useful for examining curved trajectories and variation in slopes. Coordinated analysis extends this logic across cohorts using comparable models, while meta-analysis synthesizes findings from studies that may use different instruments and follow-up intervals. These approaches answer related but distinct questions. A meta-analysis can offer broad precision while inheriting systematic limitations of the original studies; a large cohort can offer repeated detail while representing a narrower population. Graham et al., 2020; Bleidorn et al., 2022.
The interval between assessments affects measured rank-order consistency: longer intervals allow more cumulative change. Reliable change assessment also requires attention to measurement precision, consistent construct meaning, item wording, age suitability, and changes in the composition of the participating sample. Missing data cannot automatically be interpreted as random. People who discontinue follow-up may differ systematically in health, education, work status, or personality. Longitudinal sophistication improves inference but does not by itself transform observational age associations into causal laws. Roberts and DelVecchio, 2000; Costa et al., 2019.
Self-report, informants, and behavioral evidence
Self-report inventories can efficiently capture how people perceive their typical habits, feelings, and motivations, yet they are vulnerable to changes in self-understanding, social desirability, recall, and reference groups. Informants observe selected aspects of a person's behavior, and their judgments are influenced by relationship context and what they witness. Behavioral observations and repeated daily assessments add information about context-specific expression but have their own sampling limitations. Agreement across methods strengthens a conclusion, especially when the same developmental construct is represented differently across life stages. Costa et al., 2019; Caspi et al., 2003.
Between-person and within-person results must remain distinct. If people who are generally more conscientious tend to have better routine organization than their peers, it does not follow that any individual's conscientiousness will reliably rise each time their routine becomes more organized. Averages across people and changes within one person address different statistical levels. Intensive longitudinal methods and experience sampling can illuminate processes occurring over days and weeks, while longer studies determine whether altered routines correspond to persistent developmental differences. Graham et al., 2020.
Measurement invariance, cohort effects, and causality
A developmental score is informative when the assessment continues to measure comparable characteristics at different ages and in different populations. Measurement invariance is especially important where vocabulary, cultural expectations, physical capacities, and age-relevant behavior vary. Apparent personality change can emerge when an item acquires a new meaning. Cross-cultural research broadens inference but also requires translated instruments, representative samples, and attention to differential opportunity structures. A global Internet sample has reach and limitations; it does not substitute for random population sampling. Costa et al., 2019; Bleidorn et al., 2013.
Causal inference is the central frontier. Age itself cannot be randomly assigned, and life events often involve strong selection effects. The strongest plausible tests combine preregistered longitudinal models, comparisons between exposed and nonexposed people, repeated measurements before and after transitions, sensitivity analysis, and randomized interventions where appropriate. Even then, theories should distinguish evidence that a trait changed from evidence identifying precisely why it changed. Reviews of lifespan personality science describe trait continuity and maturation as established while treating many proposed explanatory mechanisms as preliminary or incompletely tested. Costa et al., 2019; Bühler et al., 2024.
Cultural, Historical, and Ethical Interpretation
Age is embedded in history. Educational schedules, employment institutions, migration, family expectations, conflict, technological environments, and longevity affect what opportunities and responsibilities appear in particular decades. Similar population trends across cultures can coexist with different timings and magnitudes. Cross-cultural findings on personality maturation show both patterns of generality and context-dependent variation. Scientific reporting should describe the sampled cultures, instruments, ages, and observational design before presenting a pattern as universal. Bleidorn et al., 2013.
Personality data can inform understanding of development, but group findings are poor substitutes for evaluation of an individual. Rank-order stability does not establish destiny; a changeable trait does not authorize blaming someone for difficulties shaped by disability, illness, discrimination, poverty, or constrained opportunities. Development is not a moral scorecard. Clinical disorders require their own diagnostic procedures and cannot be inferred from an elevated temperament dimension, an online inventory, or an atypical developmental path. For the clinical distinction, see Personality Disorders vs Personality Traits: Clinical Differences. Costa et al., 2019.
The privacy of longitudinal psychological records is also an ethical concern. Measurements collected over decades can reveal sensitive changes in mental well-being, relationships, work, and social circumstances. Research communication should avoid reducing complex lives to fixed character labels or turning correlations into mechanistic predictions. Population-level findings are most useful when understood as evidence about distributions and conditions under which different pathways become more likely. Haehner et al., 2026b.
What the Current Evidence Establishes
Established findings include the increase in rank-order stability through childhood and early adulthood, persistent average changes in several broad trait dimensions, individual differences in developmental trajectories, and meaningful contributions from both genetic and environmental differences. Meta-analytic evidence also indicates substantial stability of population-level personality variance across much of the lifespan. These conclusions rest on many longitudinal studies and independent research programs, although their magnitudes and life-stage patterns depend on sampling and measurement choices. Bleidorn et al., 2022; Haehner et al., 2026b; Haehner et al., 2026a.
Evidence is more limited for precise causal stories about why a specific person changed at a specific age. Social investment, habitual behavior, motivational adaptation, and person-environment transactions provide credible explanatory frameworks, but effects of individual life events are often small and heterogeneous. Intervention research supports some degree of intentional personality change under studied conditions; it cannot justify broad promises that every personality feature can be changed rapidly or indefinitely. The 2022 and 2026 syntheses also refine earlier narratives, illustrating how the evidence base changes as more cohorts accumulate. Roberts et al., 2005; Bühler et al., 2024; Stieger et al., 2021.
Questions readers often ask
At what age does personality become stable?
Relative personality stability typically increases from childhood into young adulthood. The large 2022 meta-analysis found little evidence that rank-order stability continues rising systematically after about 25, while average levels and individual trajectories continue to change across later decades. Age 25 is therefore an approximate feature of an aggregated trend, not a point at which personality is finished. Bleidorn et al., 2022.
Does childhood temperament determine adult personality?
Early behavioral styles help predict some later tendencies at the group level, as shown in longitudinal cohorts following children into adulthood. Prediction is incomplete because contexts, habits, development, and measurement evolve. Childhood inhibition, intensity, or activity is not a diagnosis and cannot specify an individual's adult future. Caspi et al., 2003.
Do people become more mature with age?
Many cohorts display average changes in characteristics related to responsibility, self-regulation, and emotional stability, particularly during early adulthood. The timing, size, and direction vary by characteristic, age, culture, and person. Maturity in this literature names a statistical pattern; it does not certify everyone's moral or psychological superiority as they age. Roberts et al., 2006; Bleidorn et al., 2013.
Can a major life event change personality?
Transitions may accompany lasting changes, especially when they reorganize habits and responsibilities, but meta-analytic effects are generally modest and differ by event. Existing dispositions can also influence which events people experience. Good evidence requires considering selection and the lived meaning of the event. Bühler et al., 2024.
Can adults deliberately change their personality?
Controlled research indicates that supported behavioral change programs can shift personality measures and sometimes informant impressions over months. Average improvement in research participants does not guarantee an outcome for each person, and follow-up evidence remains important. Concrete behavior, sustained opportunity, and repeated practice are appropriate targets for evaluating meaningful change. Stieger et al., 2021; Roberts et al., 2017.
Related Articles
The main scientific chapter on personality traits, temperament, and individual differences establishes the wider conceptual domain, including traits, states, temperament, and alternative models. How Stable Are the Big Five Personality Traits Across the Lifespan? analyzes model-specific rank-order and mean-level evidence. Can Big Five Personality Traits Change? Evidence Across the Lifespan examines applied and intervention findings for that model. Personality Traits vs States: How the Big Five Changes Across Situations addresses situational expression. Personality Disorders vs Personality Traits: Clinical Differences clarifies the clinical boundary.
Can Personality Change? Evidence from Longitudinal and Intervention Studies — Reviews naturally occurring personality development and intervention-associated change with causal and clinical caveats.
Person-Environment Transactions: How Experiences Shape Personality — Explains selection, evocation, reactions, and reciprocal processes across individual development.
Social-Cognitive Personality Theory: Reciprocal Determinism and Behavior — Explores person-behavior-environment reciprocity, agency, cognition, and explanatory evidence.
Differential Susceptibility Theory: Why People Respond Differently to Environments — Reviews variation in responsiveness to supportive and adverse conditions, developmental models, and replication questions.
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