The conclusions that are drawn from black athletes dominating the 100m final go a long way to explaining attitudes in wider society, argues Matthew Syed.
The 100m final at the World Athletics Championships this weekend will be won by a black athlete.
Every winner of the 100m since the inaugural event in 1983 has been black, as has every finalist from the last 10 championships with the solitary exception of Matic Osovnikar of Slovenia, who finished seventh in 2007.
Assuming that this success is driven by genes rather than environment, there is a rather obvious inference to make - black people are naturally better sprinters than white people. Indeed, it is an inference that seems obligatory, barring considerations of political correctness.
But here's the thing. This inference is not merely false - it is logically flawed. And it has big implications not merely for athletics, but for the entire issue of race relations in the 21st Century.
To see how, let us examine success not in the sprints but in distance running, for this is also dominated by black athletes. Kenya has won an astonishing 63 medals at the Olympic Games in races of 800m and above, 21 of them gold, since 1968. Little wonder that one commentator once described distance running as "a Kenyan monopoly".
But it turns out that it is not Kenya as a whole that usually wins these medals, but individuals from a tiny region in the Rift Valley called Nandi. As one writer put it: "Most of Kenya's runners call Nandi home."
Seen in this context, the notion that black people are naturally superior distance runners seems bizarre. Far from being a "black" phenomenon, or even a Kenyan phenomenon, distance running is actually a Nandi phenomenon. Or, to put it another way, "black" distance running success is focused on the tiniest of pinpricks on the map of Africa, with the vast majority of the continent underrepresented.
The same analysis applies to the sprints, where success is focused on Jamaicans and African-Americans. Africa, as a continent, has almost no success at all. Not even West Africans win much.
The combined forces of Mauritania, Guinea-Bissau, Sierra Leone, the Republic of Guinea, Liberia, Ivory Coast, Togo, Niger, Benin, Mali, the Gambia, Equatorial Guinea, Ghana, Gabon, Senegal, Congo and Angola have not won a single sprinting medal at the Olympics or World Championships.
The fallacy, then, is simple. Just because some black people are good at something does not imply that black people in general will be good at it.
Imagine a similar argument using the Central African Bambuti, a black tribe more commonly known as Pygmies. With an average height of 4ft we could assert that the Bambuti are naturally better at walking under low doors. Would it be legitimate to extrapolate that black people in general have a natural advantage at walking under low doors?
Our tendency to generalise rests on a deeper fallacy - the idea that "black" refers to a genetic type. We put people of dark skin in a box labelled black and assume that a trait shared by some is shared by all.
The truth is rather different. There is far more genetic variation within racial groups (around 85%) than there is between racial groups (just 15%). Indeed, surface appearance is often a highly misleading way of assessing the genetic distance between populations.
This evidence demonstrates how absurd it is to engage in racial generalisations - how crazy it is to witness a tiny group of black people winning at, say, the 10,000m and to infer that all people who share the same skin colour share an aptitude for 10,000m running.
But our subconscious assumptions about race have more than merely sporting implications.
Consider an experiment in 2003 by Marianne Bertrand and Sendhil Mullainathan, two American economists. They drafted 5,000 CVs and placed archetypal "black" names such as Tyrone or Latoya on half of them and "white" names such as Brendan or Alison on the other half. They then divided the white CVs into high and low quality and did the same with the black CVs.
A few weeks later the offers came rolling in from employers, and guess what? The "black" candidates were 50% less likely to be invited to interview. Employers were using skin colour as a marker for employment potential, despite the fact that the candidates' CVs were identical.
But that's not all. The researchers also found that although high-quality "white" candidates were preferred to low-quality "white" candidates, the relative quality of "black" CVs made no difference whatsoever.
It was as if employers saw three categories - high-quality white, low-quality white and black candidates. To put it another way, the subliminal assumption that causes us to think that black people are all the same has powerful real-world consequences.
For many economists, this assumption, which gets under the radar of our conscious thought, explains why black people still lag behind white people in economic development more than four decades after the introduction of race-relations legislation.
Recognising that we have these biases is a good place to start in trying to combat them. And a good way of tracking progress is to watch a 100m final and see whether we fall into the trap, when seeing eight contestants with black skin, of inferring that black people are naturally better sprinters.
Matthew Syed is the author of Bounce: The Myth of Talent and the Power of Practice