Cognitive gerontologists well know, but keep very quiet about a serious problem for our science: There are two different kinds of older people but we have only studied one of them. We know, greatly admire, value and cherish the tiny minority of Laboratory Elderly who volunteer for our experiments but have learned very little about the far larger number of Free-Range elderly who don’t. People who agree to visit our laboratories, even once are, by that token, much healthier for their age than most of their generation. For example, in the UK, over 60% of men over the age of 70 are not well enough to come to laboratories to be tested. To leave these out is a bad lapse because evidence mounts that it is not how old people are but how well they are that predicts most of the mental changes that they experience. 1 In all our studies women are much more numerous than men, not only because they live longer but also because they are far more willing to volunteer. We are all honest scientists but disingenuous about this extreme self-selection. Indeed we often proudly stress that our volunteers have been deliberately selected for being exceptionally healthy and well-motivated. We may even boast that they are retired academics who, we conspire to agree, may be sensibly compared with easily accessible undergraduates.
Free-Range Elderly are unwilling to make inconvenient trips to do boring things in dull laboratories. People who can be cajoled to volunteer, even for a single experiment, are gallant and exceptional members of their age-groups. The tiny minorities who persist with longitudinal studies for decades are something else again. Wonderful Manchester and Newcastle volunteers came back for twenty years, very often in bad weather, rewarded only by coffee, conversation and Jaffa Cakes. They are inspiringly unusual human beings. Moreover, the longer volunteers persist in longitudinal studies the more extremely atypical they become. Robust 60-year-olds are commonplace. Hale and merry 70-year-olds are fewer but people in their 80’s and 90’s, who agree to be tested even once, let alone to continue with a study for decades are an extreme elite.
Eminent colleagues long ago warned that elderly volunteers are atypical because they are, on average, much healthier and more able than most others of their ages. ,2,3,4,5,6,7 For me a more disquieting realisation is how very similar to each other they are. Not just because they are all healthy, unusually intelligent, well-educated and prosperous. They are also more kindly, more tolerant of gerontologists and of most other humans, more generous, and more eager ” to do something to help science” – even when they are sceptical of us and the things that we ask of them. I gained this insight while running group testing sessions in Manchester and Newcastle that evolved into social encounters lasting long beyond the single hours that we planned for them because of avid exchanges of information, gossip, and the details of the experience of being old and gradually getting even older. These were evidently communities of people who are, in all senses, extremely like- minded.
This raises unacknowledged problems for interpreting their data because they vary much less from each other than they should if we are to suppose that they represent the entire populations from which they are drawn. This flaw cuts to a key issue in cognitive ageing: arguably it is much more important to discover the factors that account for the splendid increases in the diversity of individuals’ paths of change than to record dull averages of general declines 8.
To study Free-Range rather than Laboratory Ageing we shall need field work. There are good times and places for this, such as during the “Pensioners Hours” that seem to start as soon as supermarkets open. Probably the most pleasant time and place to appreciate the rich diversity of North European Ageing is in warm bright Tenerife where thousands of old Finns, Germans, Scandinavians, Russians and Brits, who have this lucky chance, escape their bleak winters.
My holiday balcony in Tenerife is separated from Mexico by only a narrow promenade for dog-walking and the stirring, glittering Atlantic. Here dog-walking is an exotic technique. Below a 5 meter high promenade there is a narrow margin of scrub and tufa and an entire ocean to dispose of dog-dirt more pleasantly than messing with plastic bags. You use a very long lead, let your dog down at the west end where the drop is slight, and gently amble east until it has done its things. To retrieve the dog you walk back to the shallow west end – unless, like some testy people, your patience fails and you brutally haul it up. Hopefully it is wearing a harness rather than a collar.
The dogs seem very much alike, as if they are all mutating into the same species of portable vermin, but their elderly owners are magnificently diverse. They stride, or limp, or shuffle or even run, wearing silly gilets, with unfeasibly many pockets, baseball caps, always peak-forward and never back-to-front, and straw hats or insecure bandanas. Some carry Nordic walking poles to conquer treacherous pavements. One fine man, wiry and brown, strides with the kind of massive, potentially lethal richly carved ceremonial staff that is captured in photos of 19th Century African tribal elders. The weird promenade tracks along the ocean rim until it suddenly funnels into a narrow passage between tenements whose inhabitants keep sofas and tables out on the street to sit and eat and talk among themselves while feral elderly thread between them to a restaurant area. Where hustling waiters lurk like ambush predators and my co-evals read menu-boards on stands, solemn as Professores Emeritorii giving Keynote Addresses from lecterns.
I shall too soon be back in dank chilly Oxford, where there is neither ocean nor bright glitter, and I shall work with tables of numbers that describe only enormously valuable, clever, generous, cheerful, kind and patient laboratory elderly. The passagio of my magnificently diverse feral contemporaries will still progress through my mind, with ceremonial staves, walking poles, sandals, purposeful boots, unwise baggy shorts, bronzed noses, and brillo-pad or wind-wisped gossamer hair. They fascinate and puzzle me. I know so very little about them. They are the ones that got away.
- Rabbitt, P., Lunn, M., & Wong, D. (2008). Death, dropout, and longitudinal measurements of cognitive change in old age. The Journals of Gerontology Series B: Psychological Sciences and Social Sciences, 63(5), P271-P278.
- Lachman, R., Lachman, J.L. & Taylor, D.W. (1982). Reallocation of mental resources over the productive lifespan: assumptions and task analyses. In F.I.M. Craik and S. Trehub, (Eds). Aging and the Cognitive Process, New York, Plenum Press.
- Baltes, P.B. (1968). Longitudinal and cross-sectional sequences in the study of age and generation effects. Human Development, 11, 145-171.
- Baltes, P.B. and Neselrode, J. (1970). Multivariate longitudinal and cross-sectional sequences for analysing ontogenetic and generational change: a methodological note. Developmental Psychology, 2, 163-168.
- Baltes, P.B., Cornelius, S.W. and Nesselroade, J.R. (1979). Cohort effects in developmental psychology. In J.R. Nesselrode and P.B. Baltes, (eds) Longitudinal research in the study of behaviour and development. New York, Academic Press.
- Schaie, K.W. (1989). Perceptual speed in adulthood: cross-sectional studies and longitudinal studies. Psychology and Aging, 4, 443-453.
- Schaie, K.W. (1990). Correction to Schaie (1989). Psychology and Aging, 5, 171.
- Rabbitt, P. (1993). Does it all go together when it goes? The Nineteenth Bartlett Memorial Lecture. The Quarterly Journal of Experimental Psychology, 46(3), 385-434.