The irresistible vs. the immutable – Pat Shipman’s paleoanthropological findings

The irresistible vs. the immutable – Pat Shipman’s paleoanthropological findings – column

Gilbert Rogin

It takes a tough scientist to work a dig in the stifling heat andchoking dust of the Kenyan plains, and an even tougher one to write an article as forthright as ”The Hard Part Was the Hard Parts,” which begins on page 70. And the story’s author, Pat Shipman, an assistant professor of cell biology and anatomy as well as an associate research scientist in the department of earth and planetary sciences at Johns Hopkins, is indeed a rigorous woman whose work is painstakingly and elegantly done.

Using a scanning electron microscope on fossilized bones to helpshow how early carnivores and hominids lived and hunted, she’ll zero in on a dent in a baboon’s thigh bone and after careful scrutiny be able to determine that an axe- wielding Homo erectus detached it from the animal’s hip. And not only can she tell from examining tooth and tool marks on a bone whether an animal or a human did the killing, but she can also tell whether it was for meat or for skin and sinew. In 1981, in one of the most provocative paleoanthro pological findings in years, she reported what’s believed to be the first evidence of prehistoric human butchery of nonhuman primates (DISCOVER, Aug. 1981).

But, as Shipman points out in her article, the data collected ina dig may ultimately not fit the most meticulous hypothesis. This is because paleoanthropology doesn’t fit the classic description of how science progresses. Thomas Kuhn’s book The Structure of Scientific Revolutions lists the repeated phases that many scientists go through, from descriptive data- gathering to elaborate testing of theories. The experimental sciences deal in predictions. But the historical sciences–L of which paleoanthropology is one–deal in what Shipman calls retrodictions, the tracing of past events. She found this out when she and her colleagues returned to Kenya in 1984 to test an ”irresistible hypothesis,” which they had published in Nature, that one site studied almost a decade earlier was a place where hominids killed and processed animals. Shipman relates how she and her partners were ambushed by the facts, and . . . Well, we won’t give you any more details about her paleoanthropo logical detective story, but we’ll tell you that Shipman isn’t especially unhappy about its outcome. ”We didn’t use to catch our own mistakes,” she says. ”Quite often, once a site was investigated, people didn’t go back and look at it again. And because of that, it sometimes makes one wonder about some of the conclusions that were drawn when a site was surface-collected and not really excavated.”

Was Shipman, 37, a native of Scarsdale, N.Y. and a graduate of Smith College and NYU, who’s married to the distinguished paleontologist Alan Walker, embarrassed when the hypothesis she’d published was found wanting? ”Well,” she says with a laugh, ”it would have been fun, of course, if we’d been right. But I’d much rather find out myself that we were wrong than to have others do it. That would’ve been embarrassing.”

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