The Inner Level

by Richard Wilkinson

  This is not to deny that there are differences in ability, skills and interests, or that those nearer the top often score better on at least some of the most highly regarded measures of ability. The distribution of ability in society would, however, look rather different if – for instance – people were rated on the various kinds of technical ability used in manual occupations, or on driving skills, DIY know-how, or the skills involved in living on a small income. Even though some kinds of ability are privileged over others, our argument is not with the measures of ability but, instead, concerns where those differences in abilities come from.

  Boris Johnson’s crediting differences in intelligence to biology, and his belief that people have a ‘natural’ endowment of talent, mainly determined by the genes they inherit from their parents, are not new. At least since classical times, there has been a tendency for the rich and powerful to believe – and encourage others to believe – that members of each class in society are made of different stuff. Plato imagined that members of the ruling class had souls made of gold. In the class below them were people with souls of silver and, below them, of bronze or iron.272 Class and racial prejudices have always been bolstered by beliefs that there are innate differences in ability between groups that explained social position – from philosopher kings at the top to slaves at the bottom. As we now know, however, social classes are not based on genetic differences.273

  SHARED INHERITANCE

  Any genetically determined characteristic that confers a substantial survival advantage will tend to become universal among members of a species. We all have two eyes because binocular vision is so useful. Whole populations have lighter or darker skin to provide the appropriate level of protection from sunlight needed at the latitudes where their forebears lived. Of several hundred primate species, we are almost the only one to have whites to our eyes; in the others the sclera is brown. As we are a highly social species the ability to follow each other’s gaze and see what anyone is looking at is advantageous and has therefore become a universal human characteristic. It is therefore hard to imagine that if any specific genes for intelligence conferred significant survival advantages that they would not have become universal among human beings. Nevertheless, the improbable idea that some groups of humans have particularly advanced ‘intelligence’, which substantially enhances their ability to solve almost any kind of problem, while others are persistently poorly endowed, has until relatively recently appeared to have scientific support, and remains widely held.

  WE’RE GETTING SMARTER …

  The belief that there are major genetic differences in intelligence has been struggling to survive evidence that the intelligence of whole populations has been increasing rapidly over time. In the 1980s, Professor James Flynn, a psychologist in New Zealand, first began to publish studies showing that in many different countries – indeed wherever he could find data allowing him to make accurate comparisons over time – populations had made huge gains on IQ tests across the twentieth century. This fact has now become so well established, and has been observed so widely, that it is known as the ‘Flynn effect’. Among developed countries, measurements have been made in the USA, fifteen European countries, four Asian countries, Australia, Canada and New Zealand. All show the ‘Flynn effect’. Developing and emerging economies, including Kenya, Dominica, Brazil, Turkey and Saudi Arabia, are now also making explosive gains.274 The typical rate of increase in IQ is close to three points per decade. By the IQ standards of the year 2000, that means people living in 1930 would have had an average IQ of about 80, regarded as the point below which ‘dullness’ becomes ‘borderline deficiency’. Clearly, if people today are massively more intelligent than their own parents and grandparents, then IQ tests are not measures of anything we can regard as innate intelligence.

  Flynn points out that IQ tests measure ‘habits of mind’ that are cultural and learned, rather than innate. He describes modern, Western habits of mind as being like wearing ‘scientific spectacles’ – we see the world through the prism of scientific learning, rather than from a purely practical point of view. Thus, the ‘correct’ answer to a question on an IQ test that asks, ‘What do dogs and rabbits have in common?’ is that both are mammals (scientific classification), rather than that dogs can be used to hunt rabbits (a practical view, more likely to be offered by someone not raised with Western culture and education). IQ tests are geared towards measuring hypothetical logical thinking, as well as symbolic thinking, and their consequences. It seems likely that through differences in work and life circumstances, some sections of the population get their ‘scientific spectacles’ before others.

  Flynn suggests that there have been substantial changes in the cognitive skills valued by society, taught by educators and rewarded in IQ tests, rather than a gain in innate intelligence. He says ‘the ultimate cause of IQ gains is the Industrial Revolution. The intermediate causes are probably its social consequences, such as more formal schooling, more cognitively demanding jobs, cognitively challenging leisure, a better ratio of adults to children, richer interaction between parent and child.’ In other words, the enormous gains in IQ over the twentieth century are socially constructed, not genetic. He also reminds us that few developing nations now have average IQ scores as low – for example – as the USA had in 1900.

  WHAT ABOUT THE TWIN STUDIES?

  Scientists seeking to understand inheritance and whether it is genes (nature), or environment (nurture), which primarily affect human characteristics, traits and behaviours, have for a long time studied people who are genetically related to one another. Studies of twins have been particularly useful, and most useful of all have been studies of identical twins raised apart. Identical twins share 100 per cent of their genetic make-up, and even when they are brought up separately, they score much more like each other on an IQ test than two people randomly selected from the population. It was this evidence that led scientists to conclude that intelligence is highly heritable, predominantly genetic, and that the environment plays a much smaller role.

  With hindsight, we can see that this finding has actually been misleading, not because the results are incorrect in themselves but because of the way they have been interpreted. In fact, twins reared apart tend to have been brought up in much more similar environments than two people chosen at random from the population. Imagine identical twins adopted at birth into two different families – they may well be adopted within a restricted geographical area, for example by adoptive families in the same local authority, perhaps by families with quite similar socio-economic status, from the same ethnic and cultural background, and so on. Despite being reared apart, their environments might not differ very much.

  Still more important is the fact that small genetic differences tend to become dramatically amplified by the environment. Imagine, for example, someone who, perhaps for genetic reasons, is marginally better at sport than others. As a result, they are more likely to enjoy it and to practise more. They may then be picked for the school team and given more coaching, further improving their performance. In this kind of way, small innate differences in ability are magnified by being nurtured through the way people are set off on different developmental trajectories of behaviour and environmental choices. The same is true of almost any slight advantage or predisposition we might start off with, whether it is learning to read at a young age, being musical, having an aptitude for mathematics, or a curiosity about how things work. Having any such aptitude tends to mean people do more of that activity, they enjoy it more, get better at it, are rewarded for doing it well and develop it further – in effect, we choose activities and circumstances which amplify our ability to do things we were initially good at. As a result, small biologically based differences in our aptitudes nudge us a little in one direction or another so that small initial differences get magnified and developed by what we choose to do. Similarly in twin studies: differences or similarities between twins or non-twins, whether reared together or apart, which may in
these studies be attributed to genetics, are actually reflections of small genetic differences or similarities that have been amplified by the activities and environmental choices people make.

  There are a number of concrete examples demonstrating almost exactly these processes in action. Rather than genetic advantages, we shall look at examples of how random differences in children’s ages confer small biological advantages, which are then amplified in ways closely analogous to those in which genetic advantages are amplified.

  Entry into school systems is almost always determined by an annual cut-off date. If, for example, children must be aged five years by 1 September in any year to start school, then children born just after that date will enter school almost a full year older than children in the same classroom with birthdays just before 1 September. The children who are among the oldest in their class have a small but significant developmental advantage over their classmates. Studies show that, as a result, they do better in many ways: their educational attainment is better, they have more friends, take on more leadership roles, and are more likely to succeed throughout life.275 In an international study, relative age when entering primary school was found to have a positive effect on long-term test scores in ten out of the sixteen studied countries.276

  People used to think that this might be because summer-born children were more exposed during early foetal development in the womb to maternal infections during the previous winter months. But we now know that the lasting benefits of being one of the older children in a class holds true whatever the cut-off date for entry. A small developmental advantage becomes magnified through classroom interactions in just the same way as small genetic differences in one or other skill or ability can become magnified by practice as people select and are selected by their environment.

  The same mechanism explains why more than twice as many professional hockey players are born in the first three months of the year than in the last three months.277 Figure 6.1 shows the data for American and Canadian players selected to play in the National Hockey League. The cut-off birth date for youth hockey leagues (and therefore access to training, practice and other opportunities) is 1 January, so those born in the early months of the year are, on average, bigger, stronger, faster and more developed than their team-mates born later in the same calendar year. Their chances of being recruited into elite training programmes, travelling teams, scholarships and so on are therefore higher from the start, resulting in significantly different trajectories for those born earlier in the year. A large number of studies have now identified these processes in at least fourteen other sports including football.278, 279

  Figure 6.1: Players born earlier in the year are more likely to play in National Hockey League teams.277

  Sporting ability may be a better guide to forms of ability relevant to social mobility than some would expect. It would be easy to imagine that physical and mental abilities are quite separate. But a recent study found that sporting prowess depends not only on physical ability but also on very rapid information processing in quickly changing contexts.280 Tests found that a group of cognitive abilities known as ‘executive functions’ (including working memory, mental flexibility and self-control) were not only much higher in male and female footballers playing in league teams, but were higher in first- compared to second-league players. The same study also found that the results of executive function tests were predictive of the numbers of goals scored by players. This should caution us from saying someone is simply ‘good with their hands’ as if that did not depend on the brain guiding their hands (or feet!). We would not, after all, say that a good novelist is simply good with a pen – or perhaps keyboard.

  Just as minor initial differences in ability arising from any source – including the way birth dates can affect selection – are amplified by what people choose to do, so the differences in ability from other sources, including those attributed to genetics, are also amplified. The other side of that coin is that the importance of all the things we do which develop our skills and abilities have generally been underestimated. A pianist might have a small genetic aptitude which contributed to taking up or persevering with the piano, but the overwhelming determinant of ability is, in the end, practice.

  It is likely that small genetic advantages in one or other activity have such an influence on individual development because we get pleasure from doing what we are best at relative to others. That nudges us to specialize in areas where we have the greatest comparative advantage – a principle fundamental to economics and perhaps to evolution. It is probably particularly important in relationships between siblings. If your elder sibling is the sporty one, then maybe you have to be the bookish one, the practical one, or the funny one. A mechanism of this kind, which pushes siblings to differentiate themselves from each other, would explain why some research suggests that siblings are no more alike than random pairs of the population.281 In effect, the important environment is sometimes less a matter of the bricks and mortar as of the subjective niche we create for ourselves.

  THE PLASTIC BRAIN

  The past several decades of research have transformed our knowledge of the extent to which our brains (and so minds) are flexible and capable of development. There are now numerous studies using brain scans that show that when we exercise the ‘muscles’ of our mind, through different kinds of learning and practice, we shape the very structure and functioning of our brains. There is a celebrated and well-known study of the brains of London taxi drivers that shows that their hippocampi – the area of the brain used (among other things) for navigating through three-dimensional space – are enlarged after (and not before) acquiring ‘The Knowledge’.282 (To get their licence, taxi drivers have to pass a stringent test that involves memorizing the location of 25,000 streets and 320 main routes across London without looking at maps, using satellite navigation or asking for help via radio.) The brains of professional musicians (when compared to those of amateurs and non-musicians) similarly show changes that are particularly closely related to the intensity of practice.283 In another study, volunteers who learned to juggle were found to undergo structural changes in brain areas involved in the processing and storage of complex visual motion.284 Other studies have shown changes in the brains of people who learned a second language or were given golf lessons, in dancers and tightrope walkers, and in volunteers who practised mirror reading for fifteen minutes a day for two weeks. And a study of medical students revising for exams showed that learning so much abstract information led to structural changes in particular areas of their grey matter.284

  There can now be no doubt that with practice and training our brains adapt to make us better at whatever it is we do. The brains of architects, footballers, lawyers, psychologists, musicians, cabinet makers, policemen, accountants, motor mechanics and artists will each develop to give them particular abilities, sometimes amplifying earlier predispositions that led to an initial interest in a field. Nor are these effects confined to the young. Similar processes have been shown in middle age and beyond. Though brain plasticity declines in old age, studies indicate that even the brains of the elderly respond to enriched environments and training.285-287 Lives can change course and our brains respond. The limitations of childhood circumstances or poor schooling need not be permanent.

  The evidence suggests, then, that what is measured by IQ tests and rewarded with financial and social advantages develops in much the same way as the expertise of a taxi driver, musician or bricklayer. What we now know about the plasticity of the human brain means that these issues are basically the same whether the skills and abilities are social, artistic, mathematical, spatial, linguistic, practical, musical or kinaesthetic. Nor should we forget that brain development is also affected by stress in pregnancy, by conditions in early childhood, by nurturing, teaching and schooling, by family circumstances, and by respect and love.

  DIFFERENT CIRCUMSTANCES

  Rather than innate ability determining where people end up in a supposedly
meritocratic hierarchy, the apparent abilities of children and their subsequent social status are instead heavily influenced by their family’s position in that hierarchy. Vast numbers of studies have now demonstrated the cognitive damage that living in poverty does to children. They also provide strong evidence that lower levels of ability among children in poorer families reflect the less stimulating and more stressful family circumstances that poverty produces. The cognitive deficits found in studies of children from poorer families show clearly that they are created, rather than being innate and unalterable givens.

  A recent study in the USA used MRI scanners to scan children’s brains up to seven times each between the ages of five months and four years. Comparing children from high-, medium- and low-income families, it found that children in lower-income families had lower volumes of grey matter (containing neural cells, dendrites and synapses), which is essential for cognition, information processing and behavioural regulation. Although there were not clear ordered differences at five months, by four years of age the volume of grey matter was around 10 per cent lower among children from less well-off families compared to the most well-off group. These differences were not accounted for by infant birth weight, early health, or by differences in head size at birth. Nor were the differences explained by maternal smoking, excessive drinking in pregnancy, birth complication, significant language or learning disorders and a number of other risk factors – children with risk factors such as these were excluded at the start of the study. Differences in brain volume between the income groups emerged and widened as children grew up and were exposed to their contrasting home environments for longer.288