In the January 2009 special edition of Scientific American there is a scathing report on evolutionary psychology (EP). The report raises concerns about the way evolutionary psychology is being carried out and the truth claims it is making. The article was written by Dr. David Butler, a professor of philosophy at Northern Illinois University.

I should point out that Butler believes that our mental capacities evolved, however, he is skeptical of the truth claims being made in EP. He says that many of the “grand and encompassing” claims lack rigorous empirical evidence. The claims may be correct, but EP does not have sufficient evidence to back them up.

Here are the four concerns he raises.

1. We cannot know our ancestors’ psychological traits.
EP claims to understand the adaptive problems that our Pleistocene ancestors faced. An understanding of these adaptive problems is essential to understanding how the human mind evolved. Yet, Butler points out, the paleontological record provides few clues about the challenges our early ancestors faced. It also says very little about their social interactions which would have played a major role in shaping how the human mind evolved to cope with social challenges. Without knowing the social and physical challenges they faced, we know very little about their psychology. If we do not know the psychological starting point, we cannot know how evolution shaped their minds.

2. Evolutionary psychologists are limited in their use of comparative methods.
To better understand how and why our adaptive mental traits evolved, one must do comparative research (i.e., compare the development of similar traits in a nearby species). However, Butler points out that our nearest living ancestors do not possess many of the same psychological traits that make us uniquely human (e.g., verbal language). Thus we lack crucial evidence needed to uncover our psychological evolutionary history.

3. EP is stuck in the Pleistocene era.
Butler says that EP relies too heavily on the Pleistocene era when describing the evolution of human psychology. He quotes the oft used statement “our modern skulls house a stone age mind” as evidence of this problem. He says “The idea that we are stuck with a Pleistocene-adapted psychology greatly underestimates the rate at which natural selection and sexual selection can drive evolutionary change.” For instance, the more recent agricultural and industrial revolutions presented challenges that greatly shaped human psychology. We are not locked in a stone-age mindset.

4. Some EP truth claims rest on shaky empirical evidence, and always will.
EP claims that it has uncovered human psychological adoptions. Much of the data supporting these claims were gathered with paper and pencil surveys (questionnaires). Forced choice questionnaires do not provide sufficient evidence to substantiate claims about how psychology adapted to social and physical environmental challenges. Thus, “the evidence needed to substantiate accounts of adaption…is scarce. And this isn’t the kind of evidence that is likely to materialize; such evidence is lost to us, probably forever.”

I have found that the same sort of arguments may be used against common descent. Specifically, as far as common descent is concerned, we cannot know exactly what took place back when organisms were supposedly evolving from one species into another because we were not there. Our evidence for common descent is largely driven by the historical fossil record. Try as we might to paint a picture of what happened, we cannot be certain. Moreover, decisive evidence that evolution across life forms will always be lacking because of the long period of time required to observe these supposed processes at work.

One final thought. Butler is not suggesting that EP close up shop. He is just pointing out its limitations and cautioning it from making unsupportable truth claims. In the same way I am not suggesting that common descent scientists stop their work. I am just pointing out its limitations and cautioning it from making truth claims that lack definitive evidence.
 


Comments

Stan

Mon, 26 Oct 2009 2:20:44 pm

"I have found that the same sort of arguments may be used against common descent."

Aw man! =:) There is so much more than just the fossil record to support common decent and I don't know why you would think the fossil record alone isn't sufficient evidence. Of course there is DNA and comparative anatomy as well as embryology to support common decent. Take a look at 'Your Inner Fish...' there are some great chapters that show how things change and are re-purposed from one species to another. For example, the bones in the ears of mammals originating as jaw bones in fish. There is evidence of this in the fossil record and in embryology. Genes for smelling certain molecules become pseudogenes as species with color vision become less dependant on a sense of smell. We (whatever 'we' were at the time) could once smell as well as dogs and still have the genes to do so, only they have mutated to where they don't work anymore. There's very little in the fossil record related to behavior and psychology but there is a vast body of knowledge dealing with common decent. Have you looked at the sequence of hominid fossils? How do you explain the divergence from modern humans as you go backwards in time? Pile that on top of the DNA, comparative anatomy and embryology evidence and you really need to work hard to deny common decent.

 

S.Faux

Mon, 26 Oct 2009 2:41:43 pm

Dave C:

Regarding: "EP is stuck in the Pleistocene era."

I don't think EP is necessarily stuck in the Pleistocene, but indeed some EP investigators have made the argument that our brains our adapted to particular eras.

Humans are reproductively more successful than ever before. We live all across the earth. Our current behavior and our current living habitats do not easily suggest a narrow specialized ancestral habitat tied to a specific geological era.

The problem is that humans are evidently generalists capable of living in a wide variety of global environments. Thus, it's hard to tie our "mind" to a particular geological era. It is a product of multiple eras, and it is well adapted to the present (assuming we do not go extinct in the near future).

Besides, how far back one must go? How many thousands of years does it take for evolution to have a noticeable effect on behavior? Do all parts of the brain evolve at the same rate? These are simply unanswered questions.

The reality is that evolution is a tinkerer. Our "reptilian" brainstem has ancient circuits for swallowing and breathing. Our limbic system has ancient mammalian circuits for memory, motivations, and emotions. And, much of our neocortex circuitry probably goes back several million years. Comparative anatomy of the brain is a revealer of our past. Our brain is a composite of the past.

Thus, to the extent that EPers do try to tie our mind down to a particular era, then they are purely speculating, and they are probably in error.

But, did the brain evolve? Yes. But, then again I am a naturalist ... (who believes in God).

 

Dave S.

Tue, 27 Oct 2009 9:44:03 am

Stan,

You are correct that there is genetic evidence for common descent, which is why I said that the "evidence for common descent is *largely* driven by the historical fossil record."

I prefer to interpret the genetic evidence as evidence for a common designer. Anyway, whatever the case may be, I think the research is good and may lead to discoveries with applications outside of evolution, such as medicine.


 

Dave S.

Tue, 27 Oct 2009 9:54:51 am

S.Faux,

I was surprised by the EP article. In my opinion it represented more of a hard vs. soft science debate - of someone from the hard sciences smacking the soft sciences in the face for not being truly scientific.

I think it was a bad move by Scientific American to publish the article. In a way it is like evolutionists eating their young. EP is a new science that is trying to find a niche and here comes the mother establishment to hinder its progress?! What is up with that?

If I were an evolutionist and asked to write the article I would have metioned all the positive things EP is doing and stated its current limitations. Then I would have given some advice on how to overcome those limitations and closed with a vote of confidence for EP.

All scientific disciplines have limitations, yet Butler makes it sound like EP's limitations are deal breakers.

My 2 cents.

 

S.Faux

Tue, 27 Oct 2009 1:13:02 pm

Dave C:

Don't get me wrong. I consider myself an evolutionary psychologist, but I prefer that speculations be labeled as such. Speculation has a place in science, as long as it is clearly labeled as such.

I am not sure what you mean by "someone from the hard sciences." Butler, as you say, is a professor in philosophy.

Butler raises good points. I had my class read his article at the beginning of the semester. Naturally, I want my students to know the strengths and the weaknesses.

But, honestly, I don't know how anti-evolutionists (especially with respect to human evolution) get around the fossil and DNA data. To me, those lines of evidence completely wrap up the issue.

Evolutionary psychology asks, "Does human behavior evolve as well?" This question is more open to debate.

 

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