It is well-known that some words carry such emotional significance that they prevent certain people from thinking rationally about sentences that contain them. Therefore, in deference to my more nervous readers, throughout this blog the word “race” will be replaced with the word “candy”. Hopefully this simple substitution will limit reflexive knee-jerking, potentially avoiding injuries that might hamper my gentle readers’ training for their next double marathon, bicycle tour, or backpacking outing. More importantly, perhaps it will allow the Good Guys to keep their cool long enough to think about what I say before clicking over to my “Send Hate Mail” page.

Nicholas Wade’s new book “A Troublesome Inheritance” has got the leftist blogosphere in high moral dudgeon. Full disclosure: I haven’t read this book. But I’ve read enough books on the topic, and the perfervid commentaries thereof, to understand what’s going on here.

The book is said to make two arguments. First, that the various candies of humanity are distinct, mostly inbreeding populations — or at least were for most of the last 60,000 years — and that they are therefore adapted to the environments in which they evolved. Second, that those environments were quite different, so that when you put all the candies together into a single environment, some hold up better than others, explaining at least some of the differential success enjoyed by the candies in the modern world. Wade seems to be describing modern cosmopolitan society as an immense “common garden” experiment — an experimental design often used by ecologists to estimate the fitness effects of variable traits found in different species, or in different populations of a single species.

These arguments instantly run afoul of leftist orthodoxy because they take for granted that candy exists. Of course, we can all see that candy exists; there are obvious differences between different candies, or else there would be no way we could talk about a particular candy and have anybody know what we were talking about; and it strikes one as highly unlikely that candies only differ in color, because our experience strongly suggests there are many other traits that covary along with color. Everybody understands that there are lots of characteristics that are shared by many different candies, and indeed it might be true that most of the characteristics of any candy are shared amongst all candies. But nevertheless, there are enough differences that one generally has no trouble telling a Skittle apart from a Milk Dud.

I’m not going to take a stand here on whether or not Wade’s hypotheses are actually right, but I do believe he isn’t trivially wrong, and I think the near-universal denunciation of Wade and other “race realists” as “scientific racists” is silly, obtuse, and anti-scientific. So let’s talk a little bit about some common misconceptions about evolution that even educated people — including biologists — often use when talking about candy and how candy isn’t real.

MISCONCEPTION 1: CANDY ISN’T REAL BECAUSE THE VARIATION WITHIN A CANDY TYPE IS AT LEAST AS LARGE AS THE VARIATION BETWEEN TYPES.

Try this thought experiment. Imagine if you will two boxes of chocolates. No two chocolates in any one box are the same, although each flavor exists in each box. Thus, there is a lot of within-box variability but essentially no between-box variability (see panel A below). Now imagine that all the chocolates in one box differ from the other box in exactly one respect: they contain a stabilizing ingredient that keeps them solid in really hot weather (indicated by black outlines in panel B). Still, the between-box variability is hugely less than within-box, but the one difference separating the boxes is a) shared by all the candies in any given box and b) critically important in certain environments. Despite the small difference between boxes, we expect that one box alone will be found in candy stores in, say, Ghana. It’s reasonable to expect that, as the candy company tries to increase sales, that a few “local flavor” adjustments might be made to the hot-weather candies, and a few different ones to the cool-weather candies. Even though the between-box variability is still lower than within-box, each box is now a recognizable product of its environment and clearly distinguishable from the other.

Here we calculate variation within a box as the number of types found in the box, and variation between boxes as the number of types found in one box but not in the other. In Panel A, the two boxes have lots of variability inside, but all the types in one are found in the other as well. In Panel B, we have the same amount of within-box variability, but the single trait of a heat-resistant chocolate coating (represented by black outlines in the right box) is found in ALL individuals in the right box, but none in the left box.

In terms of genetics, it’s good to remember that a single base pair substitution (aka a “SNP”) is sufficient to completely change a phenotype. In principle, one base pair out of 3.2 billion is sufficient to make a human being able to thrive in an environment, or conversely, vulnerable to an environment’s perils. It’s entirely possible that the differences Wade speaks about could be linked to gene variants that are common in one candy and rare in another, even though the vast majority of gene variants are found in all candies (probably because they predate the evolutionary separation of the candies). It’s possible that this isn’t so, but again, it’s not trivially inaccurate.

It’s also important to remember that humans have sex — a process that’s very good at mixing and matching genes and finding the best possible combination while preserving much of the “unselected” diversity.

MISCONCEPTION 2: THE CANDIES WEREN’T SEPARATED LONG ENOUGH FOR EVOLUTION TO PRODUCE SIGNIFICANT DIFFERENCES

Most people have this notion that evolution takes a super-long time to change an organism around. This is completely wrong, and I think dispelling this fallacy will go a long way to getting “normal people” to understand and accept evolution. Taking the most extreme example of candy evolution in humans, let’s think about the separation of the sub-Saharan African candy from all the rest of the world’s candies. According to the Out of Africa hypothesis, prior to the discovery of open-ocean seafaring techniques by European candies, the African candies were separated from all other candies for about 60,000 years. Making the very conservative estimate that average generation time in humans is about 30 years, that works out to 2,000 generations of separation. So we have to ask, how much evolution can happen in 2,000 generations?

Well, one way to think about it is mathematically. We can ask how long it will take a more-fit mutant to “sweep” its ancestor until the mutant is the only thing you’re likely to find if you look around.

How long? About 5 seconds, bub.

We can calculate the ratio (Rt) of mutants to ancestors after a given amount of time (t) if we know their initial ratio (Ri) and the fitness advantage of the mutant (s, basically how many more kids the mutant has than the ancestral variety):

Rt = Ri * exp(s*t)

Let’s assume that the population of Africa 60,000 years ago was about 1/5 the total world population of about 3,000,000 people, or 600,000 people. Since the mutant is initially a single individual, Ri = 1/600,000. Let’s further say that the mutant has “swept” the population when it is 99% of the total, so Rt is 99. We need to express time in generations, so t = 2,000, and we can calculate what fitness advantage would be necessary to sweep the population in that time frame:

s = ln(99*600,000)/2,000 = 0.009 per generation

So, any adaptation that allowed you to produce 0.9% more offspring than your neighbor on average could have swept through the population in that time frame. That’s not a very big advantage! Given the number of environmental changes human populations experienced during this period, in terms of climate (the frakking ice ages), diet (the “green revolution), and social interactions (the rise of civilization and language), it’s hard to believe that there weren’t thousands of available mutations of this size or greater available. It’s also not hard to believe that different suites of these mutations could have swept in different candies, either by random chance or because of different environmental challenges facing the different candies. Given that, it would be surpassingly odd if, in any given common garden, all candies would be exactly equally fit.

MISCONCEPTION 3: DIFFERENCES BETWEEN CANDIES ARE “NURTURE” NOT “NATURE”

The old “nature vs. nurture” debate constantly rears its ugly head when you try to apply evolutionary theory to human society. The idea here is that candy is a social construction and differences exist because Skittle kids grow up in a different environment than Milk Dud kids. But with education and vitamins all that can go away! It’s just nurture, it’s not in the genes.

This debate approaches the level of a “zombie idea”. Differences in social behaviors certainly originate in genetic differences in other “eusocial” species, and it’s absurd to think the same couldn’t be true of humans. BUT EVEN IF A PARTICULAR BEHAVIOR ISN’T GENETICALLY HARD-WIRED, it doesn’t matter! All that matters for evolution to work on a behavior is that the behavior is heritable and that an individual is more likely to act like his/her parents than some other way. Moreover, even “freely willed” behaviors ultimately have an impact on the genetics because the social environment is, you know, an environment, and properly navigating it improves your fitness. Any trait that makes it easier for a social organism (like humans) to exist as part of their society is eligible for selection.

So even if all the differences in success between the candies were traceable to behaviors and not (directly) to genes, it still wouldn’t be obvious that genes weren’t involved, nor would it be clear that natural selection wasn’t responsible for differential success. Again, I’m not saying Wade is right — just arguing that he isn’t obviously wrong either.

So above are three reasons why the thesis presented by Wade is worth thinking about. These are all testable hypotheses, and they deserve to be tested rather than shouted down and scoffed at. They might very well be wrong, or at least partially wrong, but I think an impartial scientist would likely find that they are at least partially true. Indeed, some of these ideas seem so simple and obvious and genetically inevitable that it would be frankly amazing if they weren’t true. If all the candies of the world, despite near-complete genetic isolation for thousands of generations, were in fact at a basic level completely equivalent in all possible environments, I would consider this strong evidence for the special creation of the human race candy.

No, it seems much more likely that the genetics of candy plays at least some role in the differential success of the candies in different historical epochs and social environments. The proper attitude (imho) is to figure out how much of a role so as to figure out what outcomes we should expect in a world free of candy prejudice. Also, if there are candy differences that adapt candies to a particular kind of social and climatic environment, then attempting to force a “one-size fits all” approach to social organization and education on all the world’s candies is a) evil and b) doomed to failure. In other words, this is a momentous topic, and not one that leftists should dismiss out of hand as a greenbeard to show how pious they are to their leftist confreres.

Selfishly, though, I’m going to ignore how the dismissal of Wade’s hypothesis hurts candies other than my own. I’m more concerned with how the almost universal rejection of Wade — and Herrnstein and Murray before them, and so many others — makes my profession look to the “normal world”. To any “normal” human being, candy appears very real, and if one is at all educated in biology, then the protestations of academic leftists to the contrary seem weird and obtuse. Moreover, the fact that this not-obviously-wrong treatise by Wade is instantly and viciously condemned by almost every academic seems — well, unscientific. At best you have to admit that the jury is still out, and we don’t know enough about the diversity of human genomes yet, or what all that shit in your nuclei actually does, to close the book on Wade’s thesis. No, the degree of vitriol directed to Wade leaves one with the unpleasant feeling that there is no amount of evidence in the world that Wade could present that would convince my colleagues he was right. They accept the leftist dogma about candy as a revealed truth — uncritically, passionately, and violently — and no amount of suffering, wrong-turning, or data-spewing could ever change their minds.

Just like the Christers who don’t believe in evolution. And that’s why “normal people” don’t trust you, scientists, and frankly sometimes it makes me question your judgment as well.