Does It Matter or Doesn't It?

In case you think that you have come to read my blog and feel short-changed because you found precious little mention of aging in my first entry, I follow swiftly on with a genuine bona fide entry on the psychology of aging, though it might not seem so at first.

Many readers will have heard of the controversy raised when The Bell Curve, by Richard Herrnstein and Charles Murray, was published in 1994. The book relatively cautiously argued that racial differences might in part be genetic. This produced a lively response, as the ensuing fur fight amongst the brightest and best of the world’s psychometricians amply demonstrated. By Herrnstein and Murray’s reckoning, after allowing for experimental noise thrown up by measurement techniques, etc, Black people had intelligence test scores roughly one standard deviation lower than White people (for those not statistically minded, the standard deviation (SD) is a measure of variability). This implies that Black people were ‘naturally’ less able than White people at intelligence tests. It is not surprising that a lot of psychologists took umbrage with the argument.

The purpose of this essay is not to debate whether Herrnstein and Murray were right or wrong (I personally think they were wrong, but that is neither here nor there). Instead, I want you to keep in your head the fact that a difference of 1 SD was considered a serious slur on Black people’s abilities. Now I want to turn to comparisons of intellectual abilities in older adults. We will be returning to this theme in some of my future blog entries, but this is by way of an introduction to show just how muddle-headed a lot of thinking on aging research has been.

It can be irrefutably demonstrated that older adults perform far worse than younger adults on a great many tests of cognitive skill, be it memory, visuo-spatial processing, or whatever other intellectual task you care to mention. What is interesting is the size of the difference – on many measures, older people are worse than younger people by 1.75 SDs or bigger. Now you will recall that a difference of 1 SD was enough to get people hot under the collar about racial differences. Here we have far larger differences clearly and indisputably demonstrated. Put simply, by the reckoning of these tests, older people are irredeemably beyond the intellectual pale. This might sound like hyperbole, but it is salient to remember this. A common definition of learning disability is an intellectual test score 2 SDs or more below average. By this reckoning, a high proportion of older adults are on an intellectual par with a young adult with Down syndrome, fetal alcohol syndrome, or similar.

If there were this sort of evidence presented about a racial group, we can all too clearly imagine the reaction these sorts of findings would provoke. However, to the best of my knowledge, nobody has every taken this evidence and used it as ammunition against older people. There are no cries for stopping people working past the age of 65 because it can be clearly seen that they are intellectually incapable. Nobody argues that this proves that older people are ‘naturally’ intellectually inferior. In other words, researchers have found cast iron evidence for some of the biggest group differences in intelligence ever found and that furthermore affect a significant proportion of the population, and then nothing is really done about it.

Well, not quite ‘nothing’. Researchers in psychogerontology spend a great deal of time discussing and itemising the causes and nature of age-related intellectual decline. However, nobody has ever really considered the practical aspects of much of this (except perhaps in the area of driving, but there are more problems than simply intellectual change involved in that particular situation). We are left with the feeling that here is something that might be of interest in theory but whose practical ramifications are irrelevant. A large part of the reasoning behind this is that quite clearly, a typical older adult does not behave like a young adult with marked intellectual disability. Although they might have poorer performance on many cognitive measures, there is a lot more to living everyday life than doing psychometric tests. Clearly in this instance psychometric tests are not acting as a good gauge of everyday skills.

And there’s the rub – if measures of cognitive change in older people do not reflect real life experience, why are we placing such store on them? Why, as you read this, are countless expensive longitudinal studies of aging and intellectual skills being conducted worldwide? In these straitened times, are we making the best use of the research dollar?