Comments on: Habilus and Erectus

By: Timothy Burke

Timothy Burke — Wed, 15 Aug 2007 00:14:19 +0000

Evolutionary psychology is a very small and particular branch of psychology. Contemporary psychiatric and psychological diagnostics don’t draw much on evolutionary thinking (which is one of the complaints of evolutionary psychologists, occasionally with some merit).

By: hestal

hestal — Tue, 14 Aug 2007 16:43:09 +0000

So, when the APA, in its Diagnostic and Statistical Manual, merely lists behaviors that, they say, are suffient for a diagnosis of “Antisocial Personality Disorder,” for which there is no lab test, aren’t they tellling a “just-so” story?

What makes these behaviors, “disordered?” Why aren’t they simply natural, and “ordered,” for some of us. Why aren’t the people who the APA proclaims have “Antisocial Personality Disorder,” nothing more than members of one variety of Homo Sapiens? Why aren’t these people simply “varietas antisocial?”

By: Timothy Burke

Timothy Burke — Mon, 13 Aug 2007 17:46:08 +0000

Yeah, absolutely–Dawkins and some of the other evo-psychs have a real tendency to tell what strike me as possible but by no means necessarily true fairy tales about early human existence that are based on a bad melange of reading and extrapolating from a few works of anthropology that happen to stroke their favored ideas about human nature (and ignoring anything that contradicts), Clan-of-the-Cave-Bear level visions of prehistoric hominid life, and the heavy use of particular kinds of contemporary survey research whose results are usually derived from studying 18-22 year old North American college students.

I once heard a presentation by a young evo-psych scholar who got very very angry about the just-so stories tag. He said, “Look, you can only offer an evo-psych analysis if you can demonstrate that the behavior you’re talking about is fairly universally distributed kinds of behavior in most or all human populations”. He then went on to argue for an evolutionary explanation of a behavior which had been documented extensively in the US and Western Europe…and, he added, there’s a study of 22 Kenyan women which suggests they do it too. Nothing about any human population before today (because you’d have to develop the hermeneutical skills to read documents for evidence of the behavior: no survey results available) or any contemporary human population outside of the US and Western Europe except for this one piddling and unsatisfying study of Kenyans.

And that was “universal”, established.

By: jpool

jpool — Mon, 13 Aug 2007 17:13:12 +0000

Wandering off topic with you: This is my big problem with Richard Dawkins when I’ve heard him interviewed. He makes a series of generaly cogent arguments critiquing religious belief, and then slides into these entirely speculative Just-So Stories in evolutionary psychology, to the point where I can’t see any difference between his version of religious and scientific belief except for the symbolic order they inhabit.

By: Timothy Burke

Timothy Burke — Sat, 11 Aug 2007 18:49:22 +0000

Just-So Stories by Rudyard Kipling. Fables that are intended to give a humorous explanation of how an animal acquired an anatomical feature that it's well-known for through its actions (often its misbehavior). Some people (including me) would accuse some work in evolutionary psychology, archaeology and paleontology of verging on being a just-so story at times.

By: hestal

hestal — Sat, 11 Aug 2007 15:08:23 +0000

I forgot to ask: could someone please help me understand what a “just-so story” is?

By: William Benzon

William Benzon — Fri, 10 Aug 2007 18:38:09 +0000

I was once in Ralph Holloway’s (expert in paleoneuroanatomy) lab at Columbia, looking at his skulls, bones, and endocasts. He offered the thumbnail estimate that perhaps 10% of the evidence about the brains of our ancestors was in that lab. And it wasn’t a big room. He also observed that the number of individuals represented by the collectivity of fossile remains couldn’t be more than a small fraction of 1% of the total population. There’s no particular reason to believe that that faction is a random sample of the population, and no way to estimate what biases are in play. Conclusion: we make generalizations at our (intellectual) peril.

By: hestal

hestal — Fri, 10 Aug 2007 13:33:47 +0000

Isn’t it possible that habilis and erectus are both varieties of the same parent species?

And isn’t it also possible that habilis is a variety of erectus?

And isn’t it also possible that erectus is a variety of habilis?

I think so.

And isn’t true that I have a really hard time understanding how anybody can distinguish a variety from a species this far removed in time and based on such scanty evidence?

By: pzmyers

pzmyers — Fri, 10 Aug 2007 02:15:51 +0000

Oh, and I replied directly here.

By: pzmyers

pzmyers — Fri, 10 Aug 2007 02:06:31 +0000

I don’t know what Leakey and Manthi are thinking. Both have made absolutely irresponsible and unfounded statements to the press, like this one:

“They were kind of sisters, if you like,” said Frederick Manthi, the
scientist who discovered the fossils. “Homo habilis never gave rise to
Homo erectus. These discoveries have completely changed the story.”

This is directly contradicted by the Nature paper itself, which says:

As the earliest secure evidence of Homo is found outside the known region of overlap, it is nonetheless possible that H. erectus evolved from H. habilis elsewhere, and that the Turkana basin was a region of secondary contact between the two hominin taxa.

Your scenario an entirely reasonable resolution of the situation. For some reason, the authors are saying one thing in the paper and something very different to the media.