One of the fascinating aspects of studying the process of ageing is that the theories of ageing are themselves ageing. This year marks ten years since I arrived at the Oxford Institute of Population Ageing as a Research Fellow in 2016, and the year prior, as a fledgling PhD student, I gave my first (of many) Hilary Term seminars, on the topic of successful ageing. 2026 also happens to be thirty years since Rowe & Khan first submit their seminal successful ageing paper to The Gerontologist, and forty years since their idea appeared in Nature.
Back when I was still a PhD student at Cambridge, I was preoccupied with the tension between how appealing the idea was and how awkward it became once you started asking hard questions about operationalisation, measurement, and values. That preoccupation turned into my doctoral work, and for several years successful ageing was the concept I could not escape. I spent an inordinate amount of time thinking about it, testing it, and occasionally regretting choosing such a slippery idea around which to build a PhD.
The version of successful ageing most people recognise is closely associated with the work of John Rowe and Robert Kahn. Their landmark paper, formalised a model that had been circulating in various forms for some time. In 1961, Robert Havighurst first brought forth ideas of “successful ageing” within his activity theory, which was a significant departure from more negatively oriented models of ageing such as Cumming and Henry’s (1961) disengagement theory, which basically suggested that success in aging was being able to successfully disengage with one’s social system. The Rowe & Kahn model provided an extension and expansion of Havighurst’s work incorporating additional components into Havighurst’s model.
I had the distinct pleasure of working directly with Jack Rowe on a book chapter for the third edition of the Handbook of Theories of Ageing. I was at the beginning of my time as a PhD and he was (and is) one of the most recognizable figures in the gerontological world, so to say that I was absolutely elated that he answered a cold email, would be an understatement. As Jack Rowe once told me, during a conversation the original idea for the successful ageing model was very much a back of the napkin exercise. He and Bob Kahn had sketched it out years earlier, and it first appeared publicly in a short piece in Nature in the mid 1980s. From there, it grew into one of the most influential frameworks in modern gerontology.
In its earliest form, successful ageing was defined by three components: low probability of disease and disability, high cognitive and physical functioning, and active engagement with life. It was optimistic, clear, and compelling. It was also narrowly focused on biomedical aspects of ageing, which wasn’t completely surprising given that Rowe & Kahn were both geriatricians. That narrowness became increasingly apparent as researchers began to ask who was being left out and what kinds of lives counted as successful.
My own work sat squarely in that space. Over several years, I compared definitions, tested different operationalisations, and looked at what happened when people’s lived experiences did not line up with idealised criteria. What became clear was that successful ageing is much less a state than a process. More accurately, it is a biopsychosocial process that cuts across physical health, psychological adaptation, social relationships, meaning, identity, and context. It is also deeply personal. One person’s version of success may look very different from another’s, and neither is inherently more legitimate.
That realisation creates obvious problems if your goal is tidy operationalisation and measurement. A concept that allows people to define success for themselves resists clean thresholds and simple categories, which creates problems when you are trying to use this definition in a large-scale epidemiological study of ageing. (All of this would have been useful information before I started my PhD!) At the same time, it captures something important about how ageing is actually experienced. Success is negotiated over time, shaped by circumstances, and interpreted through personal values.
Over the past few decades, the literature has slowly caught up with that reality. Successful ageing has moved away from a narrow biomedical framing toward more inclusive and diverse models. Interdisciplinary approaches, cross cultural perspectives, and greater attention to inequality, disability, and structural constraints have reshaped how ageing well is understood. There is now far more room in the concept for difference, adaptation, and complexity.
Seen that way, it feels oddly appropriate to be revisiting successful ageing at this moment. The idea itself has aged. The field has aged. I have aged alongside it. When everything is ageing at once, it seems like a good time to pause and take stock. If, ten years from now, successful ageing continues to be more inclusive, more reflective of lived experience, and more comfortable with complexity, then I think it will have aged rather well. I hope the same can be said for the rest of us!
About the Author
Theodore D Cosco joined the Oxford Institute of Population Ageing in 2016 as a Research Fellow. Dr. Cosco is a Chartered Psychologist (British Psychological Society) trained in applied social research methods (MSc 2011, Trinity College Dublin) and epidemiology (PhD 2015, University of Cambridge), and Assistant Professor of Mental Health and Aging in the Department of Gerontology, Simon Fraser University. His research interests include resilience, mental health, and the interface between technology and healthy ageing.
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