Motivation and learning are two interrelated concepts that are an essential part of lifelong learning (Wlodkowski & Ginsberg, 2017). The role of motivation is evident not only in adults' decision to engage in learning activities, but also in their ability to persist and effectively apply the knowledge they have gained in practice (Deci & Ryan, 2000).

As numerous scholars have noted, definitions and theories of motivation are not uniform (Cook & Artino, 2016; Lazowski & Hulleman, 2016). These vary depending on the disciplines and scientific orientation of the authors who study the phenomenon (Wlodkowski & Ginsberg, 2017). Nevertheless, despite this diversity of theoretical approaches, they offer different perspectives on how motivation works for different target groups and how it can be applied to achieve specific educational goals.

The objective of this systematic review study is twofold. Firstly, it seeks to map and critically analyse theoretical approaches and definitions of motivation in adult social science education between 2005 and 2025. Secondly, it aims to identify conceptualisations of motivation and theories of motivation used in the field of adult education and learning. Furthermore, it identifies the evolution of these conceptualisations and theories in the field of adult learning since 2005.

The following research questions have been posited:

RQ1: How is motivation conceptualised in the field of adult education and learning?

RQ2: What theories of motivation are used in the field of adult education and learning?

RQ3: How has the conceptualisation of motivation evolved in the field of adult education and learning since 2005?

RQ4: What changes have occurred in the application of motivational theories within the field of adult education and learning since 2005?

The present study constitutes a necessary step towards the development of a systematic framework that will facilitate a more profound analysis and identification of the fundamental determinants influencing the adult learning process. This review will assist in identifying how motivation is conceptualised in the field of adult education and learning, and which conceptualisations are minor and thus escape the theoretical scope. Research objectives RQ3 and RQ4 will be set in the context of research developments over the last twenty years to analyse the factors that have led to the shaping of current trends.

A critical analysis of these concepts is required in order to identify gaps in existing approaches and to suggest directions in which future research is supposed to be directed. A review of theoretical concepts is also essential for the development of coherent and applicable scientific knowledge (Lefrançois, 2019).

The present study was conducted in accordance with the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) methodological framework, which ensures transparency and reproducibility of the analysis process. The data collection process was conducted through the key databases, Web of Science and Scopus, utilising the following keywords: "adult* educ*" OR "adult* training" OR "adult* learn*" OR "nontraditional* lear*" OR "non-formal learn*" OR "formal learn*" OR "adult* non-formal educ*" OR "adult* student*" OR "lifelong learn*" OR "continu* educ*". The search was performed with a focus on scholarly articles from the categories of "Social Sciences", "Psychology" and "Multidisciplinary". The time frame was subsequently restricted to the period 2005 to 2025, with a focus on key journals in the field of adult education, namely Adult Education Quarterly, International Journal of Lifelong Education, Journal of Education and Work, Journal of Workplace Learning and Studies in Continuing Education. Following this selection process, a total of 1292 studies were identified, which subsequently served as the primary source of articles for the review study. The subsequent stage of the research process entailed the evaluation of the abstracts, with the objective of excluding studies deemed to be irrelevant. The selected articles were then subjected to an analytical process that traced the evolution of theoretical approaches and definitions of motivation in the domain of adult education. This analysis placed particular emphasis on identifying significant changes and shifts that occurred between 2005 and 2025.

This systematic review study will offer a comprehensive view of the development of theoretical approaches to motivation in adult education between 2005 and 2025. An important component of this study will be the categorisation of the conceptualisations of motivation and theories of motivation used. Particular attention will be paid to the broader context of research developments over the last two decades in order to identify the main factors that have contributed to shaping current trends.

Cook, D. A., & Artino, A. R. (2016). Motivation to learn: An overview of contemporary theories. Medical Education, 50(10), 997-1014. https://doi.org/10.1111/medu.13074 Deci, E. L., & Ryan, R. M. (2000). Self-determination theory and the facilitation of intrinsic motivation, social development, and well-being. American Psychologist, 55(1), 68-78. https://doi.org/10.1037/0003-066X.55.1.68 Lazowski, R. A., & Hulleman, C. S. (2016). Motivation Interventions in Education: A Meta-Analytic Review. Review of Educational Research, 86(2), 602-640. https://doi.org/10.3102/0034654315617832 Lefrançois, G. R. (2019). Theories of human learning (7th ed.). Cambridge University Press. https://doi.org/10.1017/9781108696333 Ryan, R. M., & Deci, E. L. (2000). Self-determination theory and the facilitation of intrinsic motivation, social development, and well-being. American Psychologist, 55(1), 68–78. https://doi.org/10.1037/0003-066X.55.1.68 Wlodkowski, R., & Ginsberg, M. (2017). Enhancing adult motivation to learn: A comprehensive guide for teaching all adults (4th ed.). Jossey-Bass.