Human Races are Real: Race is a Valid Scientific Category

This article was originally published on The Alternative Hypothesis

In this post I am going to argue that human races exist, look at the most common arguments I hear in favor of race denialism, and explain why, ultimately, I think they are mistaken.

It is somewhat misleading to talk about whether or not races are “real.” A race of people is just a geographically defined set of populations which, in the past if not now, lived together and bred with each-other more than they bred with outsiders. Given this definition, it is obvious that races are real because it is obvious that people who descend from Africa, Europe, East Asia, etc, are real. A better question is whether or not it is useful to categorize people by race.

Of course, this brings forth the question “useful for what?”. Well, I will argue that race is a valid scientific category, and science is in the business of predicting and explaining the world. So, for race to be a valid scientific category it needs to help us predict and explain things. Categories help us predict things when there are differences between them. If objects in one category are heavier than objects in another, then we can predict an object’s weight using this categorization scheme. Categories help us explain things when knowing which category something is in will give us a clue about why that thing possesses some trait.

So, firstly, how do members of different races differ, if at all? Well, obviously, the races do not differ in the sense that every member of one race has some trait, or gene, that no member of another race has. However, they do differ in terms of what the average person from each race is like. For one, as we all know, the races differ in mean skin color and various other “superficial” traits such as hair color and hair type, the length and density of various bones, muscle composition, etc., (Garn 1951; Pollitzer and Anderson 1989; Connor 2012; Araujo 2010). Perhaps less well known is that these differences do not stop at the outside of the skull. Dozens of studies going back over a hundred years have shown that races differ in mean brain size and modern technology has recently revealed that races also differ in brain shape (Fann et al. 2015). Racial groups also differ in their frequency of various gene variants and the rate at which they possess various diseases (including genetic diseases) (Piffer 2015; Ebert et al. 2014; Mega 2015; Piel et al. 2014) .

As we’ve already discussed, differences allow for prediction. Researchers can predict someone’s self-identified race with more than 95% accuracy using measures of their skull, and over 99% accuracy by looking at their genome (Sesardic 2010; Rosenberg et al. 2002; Tang et al. 2005; Rosenberg et al. 2005; Bamshad et al. 2003; Guo 2015).

Races also differ in their mean levels of income, educational attainment, intelligence test scores, and many other variables (Walt and Proctor 2015; Census 2014; Roth et al. 2001) Because the races differ in such a wide range of traits, grouping people racially might be useful to people in an equally wide range of sciences.

So, racial categorization can definitely help us predict things. Can it also help us explain things?

Knowing someone’s race can help us explain things for at least three reasons: the races evolved in different environments, the average culture within each race is different, and people treat others differently based on their race. For instance, knowing that someone is White might help us explain why they have light skin (evolution), why they have a certain diet (culture), and why it is socially inappropriate for them to use the “n word” (race based treatment).

So, that’s my basic case. Race allows us to make predictions about, and to explain, human differences and thus is a valid scientific category. Now, let’s look at some common objections.

“No Credible Scientists Believe in Race”

Some people feel that they do not have the needed expertise to judge the validity of race. So, they defer to the experts, and the experts tell them that race does not exist. The problem with this argument is, even though the most vocal anthropologists and biologists deny race, academic surveys show that there is no actual consensus on this topic.

Use of Race in Bilogigy Textbooks 1952-2002

Moring (2004)

Use of Race in Journals

Štrkalj (2007)

Belief in Race among Anthropologists and Biologists

Lieberman (1992)

American and European Physical anthropologists on race

Liberman (2004)

Newer  European survey

Kaszycha (2009)

A few things to note about these charts:

[1] Researchers outside of Western Europe are more likely to believe in race
[2] Biologists are more likely than anthropologists to believe in race
[3] Young researchers are more likely to believe in race than middle age ones, and the use of race in textbooks is increasing, suggesting that belief in race is on the rise in academia
[4] The only place that has a consensus on race is China. The consensus is that race exists.

“There Are No Race Genes”

A “race gene” is a gene that is present in every member of one race and only members of that race. Such genes do not exist and some people think that the non-existence of race genes shows that races don’t exist either. Obviously though, this has nothing to do with the notion of race that I am advancing here. Races differ in gene frequencies, but that doesn’t imply that “race genes” exist.

(By the way, I don’t know of any race realist in history that founded their concept of race on race genes. Prior to the 20th century, races were almost always defined by where your ancestors came from and what your hair, face, skull, skin color, and general anatomy, looked like (Hamilton 2008). In the 20th century, race continued to be tied to ancestry, but the traits scientists used to infer ancestry changed from observable physical traits to gene frequencies (Ayala 1985) (Reardon 2005 Chapter 2))

“Races Cannot Be Important Because We All Share 99% of Our DNA”

Following the human genome project, many people heard that we share 99.9% of our DNA, and so there just isn’t enough genetic variation among humans to cause significant differences.

First, we don’t share 99.9% of our DNA. The human genome project researchers that made that claim have sense retracted it (Levy et al. 2007) . But we do probably share around 99% of our DNA. That said, we also share 95-98% of our DNA with Chimps and, yet, there are some pretty big differences between us and chimps (Varki and Altheide 2009).

The reason that a small percentage difference in DNA can lead to big differences is simple: a small percentage of a huge number can still be big, and genomes are huge. The human genome is made up of 3 billion nucleotide base pairs. If you compare two people’s genomes, these base pairs won’t match up roughly 0.5% of the time (Levy et al. 2007). 0.5% of 3 billion is 15 million base pairs. To put that in perspective, the difference between someone with and without the disease sickle cell anemia is a single base pair (SNPedia).

In fact, the human species has as much or more total genetic variation than many other species of animals:


Source: Woodley (2009)

(“Heterozygosity” is the probability that two individuals will have different gene variants for the same gene. This is different than the 99.5% number which refers to base pairs, which are the building blocks of genes.)

“Human Races Are Not Genetically Distinct Enough”

You may have heard that there is more genetic variation within races than between and, so, races must not be very biologically important. The first thing to say about this is that human races are on par with subspecies in other species in terms of how much genetic variation is within and between them.

Variation version

Sources: Jackson et al. 2014, Lorenzen et al. 2008, Pierpaoli (2003), Lorenzen et al. (2007), Jordana 2003, Hofft et al. 2000, Schwartz et al 2002, Williams (2004), and Elhaik (2012).

Secondly, we’ve already seen that the genetic differences are sufficient to allow near perfect prediction of a person’s race based on their genome.

Thirdly, the average genetic difference between members of separate races is larger than average, and we’ve already seen that the average genetic difference between people is, potentially, very significant (Witherspoon et al. 2007).

“There Hasn’t Been Enough Time for Races to Evolve Differences”

From an evolutionary perspective, the question isn’t how long two populations have been separated but, rather, how large the genetic differences between them are. And, as we’ve already seen, the genetic difference between races is comparable to subspecies in other animals. How quickly these differences arose is irrelevant. But this argument is flawed on even simpler grounds: the time that the races have been separated is equal to or larger than the amount of time it took subspecies, or even species, to evolve in other animals:


Sources: Lindqvist et al. (2010), Wilson et al. (2011), Mikko and Andersson (1995), Lou et al. (2004), Peters et al. (2005), and Brammah et al. (2010)

“Human Variation is Continuous not Racial”

Some people say that human genetic variation tends to change slowly and as a function of geography. For instance, as you move further from the equator skin color tends to become lighter. The point that race deniers are making is that this gradual change in variation doesn’t have any “hard lines” that demarcate one race from another. Instead, races blend into one another and the genetic distance between populations is basically just a function of their geographic distance.

There are three things to say about this. First, scientists often group continuous variation into discrete categories. Consider, for instance:

[1] Medical researchers break continuous blood pressure variation into discrete categories such as “high” and “low”.

[2] Physicists group continuous variation across the color spectrum into discrete colors such as “blue” and “green”.

[3] Social scientists break continuous variation in income into discrete categories such as “poor” and “rich”.

Secondly, this is typical in biology. Zoologists even have a word for situations in which subspecies are connected by intermediate populations: “Intergradation”.

Thirdly, human genetic variation is not, in fact, just like the color spectrum. Same race populations are more genetically similar than different race populations even when all three populations are separated by the same geographic distance (Rosenberg 2005).

More fundamentally, the problem with this argument is that it does not address the predictive or explanatory power of race. Even if genetic variation was totally continuous, we would still need to categorize it to make predictions rather than just say “Oh, that guy? He’s somewhere on the spectrum!” And to the degree that different sections of said spectrum experience difference environments, evolution, cultures, and interactions with others, racial categorization would still have explanatory power, too.

“The Traits That Races Are Based On Are Arbitrary”

This argument postulates that you could come up with mutually exclusive groupings of people based on different traits and that, because there is no objective method of choosing which traits to use, which grouping you decide to go with is arbitrary. For instance, you could group people based on skin color and, as a result, Africans and certain groups of Indians might be grouped together. Or, you could group people based on height, in which case Indians and Africans would most certainly not be grouped together.

The problem with this argument is that racial categories are not arbitrary. We use them because they help us predict and explain human differences. Can we think of other categories that are also useful for this purpose? Sure. So what? Sometimes it’s useful to group people racially, sometimes it’s better to use a different categorization scheme and sometimes is best to combine them. (“Black, poor, diabetics…).

“Genetic cluster analysis” is worth bringing up here. In a genetic cluster analysis, you give a computer program information on a ton of people’s DNA and you tell it to sort the data into X number of groups, called clusters, so that the genetic differences within each cluster are minimized while the genetic differences between clusters is maximized. When you do this and tell the computer to group human genetic variation into 4 – 6 “clusters”, the clusters end up mirroring the races such that researchers can predict someone’s race based on which cluster they are assigned to with a 99%+ level of accuracy (Rosenberg et al. 2002; Tang et al. 2005; Rosenberg et al. 2005).

(Source: http://science.sciencemag.org/content/319/5866/1100)

Thus, races are groups of people who are more genetically similar than average. Consider next that behavioral geneticists have shown conclusively that the more genetically similar people are the more alike they will tend to be in terms of just about every trait imaginable, from body size, to intelligence, to personality (Polderman et al. 2015; Plomin et al. 2015). Studies utilizing adoption, and molecular genetic analysis of unrelated individuals, show that this is true even when the individuals in question grow up in different families and in different environments. What this implies about race, then, is that members of the same race will not only be more similar than average genetically, but will also tend to be more similar than average with respect to every trait that is heritable, which is all of them.

“Racial Categories Change across Time and Place”

Race deniers sometimes argue that people in different places, or even Westerners just a few centuries ago, had radically different ideas about who was a member of which race and that, because of this, race is invalid.

I don’t think this objection makes much sense. Who cares if people in other parts of the world, or us a few centuries ago, had different ideas about race? The question is whether or not modern western racial categorization schemes are valid scientific categories. That is, can they predict, and can the explain? As we’ve seen, they can. Moreover, they clearly reflect the actual genetic clustering of the human race. So, what’s the problem?

(Race deniers often exaggerate the extent to which western racial ideas have changed over time. That isn’t essential to the argument.)

“How many races are there?”

Some people will rhetorically ask “how many races are there?”. There is no one answer to this question, and some people think that this entails that races don’t exist. But it really does nothing of the sort.

Sometimes, given the level of information we have and what we are trying to do, it can be useful to break humans into as few as 3 races or as many as dozens. Sometimes we want to talk about “whites”, sometimes “northern Europeans”, and sometimes “Celts”. This isn’t contradictory or hard to understand. It just reflects the fact that we need varying levels of specificity in different contexts.

“Race Is a Social Construct”

At last, we’ve reached the final argument! Some people say that race cannot be a valid biological concept because it is socially constructed. My response to this? Of course it is socially constructed. Like I’ve been saying this whole time, scientific categories are tools which we invent in order to predict and explain things. The fact that we invented them tells us nothing about how well they do either of these two things.

Now, some people will say that we invented racial categories for really bad reasons (oppression, racism, etc.). I don’t think this matches the actual historical records of where racial categories came from, but even if it did, that still wouldn’t be relevant. If the Nazi’s, or the commies, created some useful scientific information for evil reasons, would it therefore be invalid? No, obviously not. Similarly, the intentions behind the creation of racial categories is irrelevant to their ability to explain and predict human differences.


So, those are the common arguments I’m always hearing and why I don’t think they work. Hopefully, this article gave you something to think about. If you’re still not convinced, I would (honestly) like to know why. So, please leave a comment letting me know.

5 thoughts on “Human Races are Real: Race is a Valid Scientific Category”

  1. Better the term Subspecies than Race. We are all different subspecies of modern homo sapiens. Whites for example, have up to 6% Neanderthal DNA. Genetic finds just within the last three months have dramatically busted former paradigms regarding diversity among our modern species.



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