Personality Change in the Light of Relationship Transitions in Partnered and Single Individuals: Study Protocol of a Prospective Measurement Burst Design

Background

Individual differences, such as the Five-Factor personality dimensions, attachment, self-esteem, or life satisfaction evolve over time (Bleidorn et al., 2022; Buecker et al., 2023; Fraley, 2002; Orth et al., 2018). While many of these characteristics have traditionally been viewed as stable (e.g., McCrae & Costa, 1994), more recent work acknowledges their malleability, especially in response to significant life events (e.g., Bleidorn et al., 2018; Fraley et al., 2021). This study builds on this evolving perspective, aiming to capture both enduring and short-term changes in these constructs during relationship transitions. Significant life events, especially normative events like beginning a new job or entering a romantic relationship, may contribute to these changes (Roberts & Wood, 2006). Among these life events, relationship transitions, such as entering a new relationship or separating, have received particular attention (Bühler et al., 2024) and are, given their prevalence and impact on an individual’s life, the core focus of the present project. A critical life stage to study the development of individual differences in light of relationship transitions is young adulthood. During these years, initiating and maintaining close relationships reflect a developmental task (Hutteman et al., 2014) and an important life goal (Ranta et al., 2014). The significance of romantic relationships during young adulthood is also reflected in the greater importance that young adults, compared to adolescents, place on their romantic partners to fulfill attachment needs (Bühler et al., 2019). Simultaneously, personality changes are more pronounced during young adulthood (Bleidorn et al., 2013, 2022; Lucas & Donnellan, 2011; Roberts et al., 2006), suggesting a potential receptiveness for adapting new roles and navigating changing environments (Roberts & Wood, 2006).

Relationship transitions and individual differences influence each other in two key ways. First, individual differences can shape the likelihood of experiencing certain events, termed selection effects. For example, extraverted or emotionally stable persons are more prone to entering romantic relationships (Neyer et al., 2014); extraverted persons are more likely to move in with their partner (Asselmann & Specht, 2020; Jonkmann et al., 2014; Specht et al., 2011); persons with higher self-esteem are more likely to enter a long-term relationship (Luciano & Orth, 2017), while more conscientious persons are more likely to get married (Denissen et al., 2019). Further, lower agreeableness and self-esteem, as well as higher neuroticism and openness are linked to the separation of a romantic couple or divorce (Asselmann & Specht, 2020; Denissen et al., 2019; Luciano & Orth, 2017; Solomon & Jackson, 2014; Specht et al., 2011). Second, individual differences can change in response to upcoming or experienced events, so called anticipation and socialization effects. Earlier studies have reported, for example, decreased neuroticism in expecting parents before childbirth and reduced conscientiousness afterward (Denissen et al., 2019); decreases in openness to experience after marriage (Asselmann & Specht, 2020; Specht et al., 2011); decreases in neuroticism after committing to a first romantic relationship (Lehnart et al., 2010; Neyer & Asendorpf, 2001; Wagner et al., 2015); and reductions in self-esteem after a relationship dissolution (Luciano & Orth, 2017). However, a recent meta-analysis has shown that findings are rather mixed, with robust effects only reported for increases in conscientiousness and life satisfaction following the entering of a new relationship, and an increase in life satisfaction following separation (Bühler et al., 2024).

While numerous studies have explored the association between individual differences and relationship transitions, they have several limitations that the present project aimed to address: Specifically, previous research has often (i) focused primarily on global self-reports of traits, neglecting momentary behaviors that may reveal more subtle or short-term dynamics; (ii) failed to consider the dynamic interplay between traits, states, and situations, limiting our understanding of how personality unfolds in everyday life; (iii) overlooked the subjective experience of life events, despite growing evidence that individual perceptions shape psychological outcomes; and (iv) relied on annual assessment intervals, which are too coarse to detect short-lived but meaningful changes. The present research project aimed to fill these gaps by studying a large sample over several waves in a prospective measurement burst design (i.e., a design that combines intensive short-term assessments—i.e., bursts—repeated across longer intervals to capture both within-person dynamics and long-term change) and encompassing a broad array of traits and states: In addition to the Five-Factor Model dimensions, we assessed a broader set of individual differences relevant to personality development and relationship functioning, including attachment orientations, self-esteem, life satisfaction, and life goals. While some of these constructs—such as attachment and self-esteem—are often seen as relatively stable, recent evidence suggests they can change, particularly in response to emotionally significant experiences such as relationship transitions (e.g., Fraley et al., 2021; Luciano & Orth, 2017). Including these constructs allows us to capture a more comprehensive picture of personality development across multiple levels.

Methods

This research project was funded by the Swiss National Science Foundation (10001G_200803) and was conducted between August 2021 and December 2025 at the University of Basel, Switzerland. Data collection took place between February 2022 and June 2025.

Design

This research project employs a prospective design to track personality change before and after relationship transitions over 2.5 years, with approximately half of the participants starting being single and the other half in a relationship. Using a measurement burst design, participants completed seven experience-sampling waves at five-month intervals. Before each wave, participants were asked to confirm their contact information and given the opportunity to postpone the wave by two weeks (“Check-in” survey). Each wave began and ended with longer surveys (“Wave-Start Global Assessment” and “Wave-End Global Assessment”) assessing socio-demographic information, personality, life events, living context, and well-being. During each wave, participants completed five brief daily surveys and an additional end-of-day recap survey each day over a period of three days (“States and Situations”, see Figure 1). This approach captures both long-term and moment-to-moment changes. A time-based design (as opposed to an event-contingent design) was chosen for consistency and logistical efficiency. This design allows us to examine the co-dynamics of trait and state personality and relationship development over time and in near real-time.

Figure 1

Discussion

This research project is one of the first to systematically investigate personality change in the context of relationship transitions by integrating trait-level, state-level, and situational perspectives. One of the key strengths of this study is its measurement burst design, which allows us to capture both broad, stable personality traits and momentary personality states across multiple time points. The measurement burst design combines intensive experience sampling with longer-term follow-ups, allowing researchers to disentangle day-to-day fluctuations from developmental trends. This methodological approach provides insights into personality change mechanisms that would be impossible with traditional cross-sectional or widely-spaced longitudinal designs. By employing narrower assessment intervals, we can track dynamic personality processes, distinguishing between selection effects, anticipation effects, and socialization effects in relationship transitions. This approach advances previous research, which often relied on annual assessments, potentially missing short-lived but meaningful changes in personality and could serve as a template for future personality research.

Additionally, this study considers the subjective experience of relationship transitions, recognizing that the same event may have vastly different psychological meanings for different individuals. For example, a separation may strongly impact personality for those who perceive it as highly positive or negative but cause no change for those who see it as neutral. By integrating self-perceived event characteristics, we aim to explain the variability in personality change across relationship transitions and address inconsistencies in prior research. For instance, by capturing both trait and state changes, we can test whether relationship transitions initially manifest as shifts in daily behaviors and emotional experiences, which may not immediately register in broad trait measures. This perspective aligns with recent findings suggesting that personality change is not solely dictated by external events but is also shaped by individual interpretations and experiences (Haehner et al., 2023).

A further contribution of this research project is its person × situation approach. By examining how situational contexts interact with personality traits and states, we will provide insights into how and when personality change occurs. This approach aligns with longstanding debates in personality psychology and contributes to a more context-sensitive understanding of personality change.

Beyond theoretical contributions, this study also has practical implications. A better understanding of personality changes in the context of relationship transitions could inform interventions designed to support individuals navigating these life events. For example, counseling, relationship coaching, and well-being interventions could be tailored to individuals experiencing specific patterns of personality and relationship development.

One limitation of the present study concerns the representativeness of the sample. As is common in research, the sample may be biased toward individuals who are more educated and female, limiting the generalizability of the findings. Although we used targeted recruitment strategies to improve balance (e.g., designing advertisements specifically aimed at men), these efforts were only partially successful.

A strength of the study is the use of optional catch-up days, which were offered to participants falling short of the within-day assessment threshold after the initial three days; most participants made use of this option, helping to ensure sufficient data coverage.

Data Accessibility Statement

The anonymized data will be made publicly available on the SWISSUbase repository upon completion of the study. The complete study codebook, all analysis scripts, and further supplementary materials are available at the Open Science Foundation: https://osf.io/rqv7j/.

Transparency Statement

We reported how we determined the sample size and the stopping criterion. We reported all conditions and variables. We report all data exclusion criteria and whether these were determined before or during the data analysis. We report all outlier criteria and whether these were determined before or during data analysis.

Ethics and Consent

This study protocol was approved by the Ethics Committee of the Department of Psychology of the University of Basel, Switzerland (Number of Approval: 003-16-1, Date of Approval: 22st October, 2021). The study is conducted in accordance with the Declaration of Helsinki. All participants received written information about the research project, benefits, and risks of participation. Participants were informed that they can withdraw from the study at any time. Informed consent is obtained prior to the start of the study.

Competing Interests

The authors have no competing interests to declare.

Author Contributions

Conceptualization: AG, JW, JLB, RPB, RW – Ideas; formulation or evolution of overarching research goals and aims.

Data Curation: ACT, FG – Management activities to annotate (produce metadata), scrub data, and maintain research data (including software code, where necessary for interpreting the data itself) for initial use and later reuse.

Funding Acquisition: AG – Acquisition of the financial support for the project leading to this publication.

Investigation: ACT, FG, KA – Conducting a research and investigation process, specifically performing the experiments or data/evidence collection.

Methodology: ACT, AG, FG, JLB, JW, MU, RPB, RW – Development or design of methodology; creation of models.

Project Administration: ACT, FG, KA, MU – Management and coordination responsibility for the research activity planning and execution.

Resources: AG – Provision of study materials, reagents, materials, patients, laboratory samples, animals, instrumentation, computing resources, or other analysis tools.

Supervision: AG, FG – Oversight and leadership responsibility for the research activity planning and execution, including mentorship external to the core team.

Writing – Original Draft Preparation: FG – Creation and/or presentation of the published work, specifically writing the initial draft (including substantive translation).

Writing – Review & Editing: ACT, AG, FG, KA, JLB, JW, RPB, RW – Preparation, creation, and/or presentation of the published work by those from the original research group, specifically critical review, commentary, or revision – including pre- or post-publication stages.