Random Samples

Science  28 Mar 2003:
Vol. 299, Issue 5615, pp. 1977

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  1. Sign of a Paleo Tongue?

    Most languages are made up of vowels and consonants, but a handful of African peoples also click their tongues. Linguists have long been fascinated by these clicks. Now a new genetic study suggests that clicks may have been part of very early human language.

    Hadza man in Tanzania collecting cells with a cheek swab brush.


    Alec Knight and Joanna Mountain of Stanford University and colleagues analyzed the DNA of two groups of Africans who speak with clicks—the San of Namibia (formerly known as the !Kung) and the Hadzabe of Tanzania. Their mitochondria and Y chromosomes both indicate that these groups have been genetically isolated from neighboring Africans for tens of thousands of years. In fact, the genetic difference between San and Hadza DNA is greater than for any pair of African groups yet studied.

    But the rarity and complexity of clicks makes it unlikely that the San and Hadzabe developed them independently, according to the researchers. So the sounds may be vestiges of a tongue spoken by a common ancestor living roughly 112,000 years ago, give or take 40,000, they conclude in a paper in the 18 March issue of Current Biology.

    Aside from clicks, the Hadzabe and San languages have nothing in common, which suggests that the clicks may have some adaptive value. Knight notes that today the San speak in clicks only when they hunt, in order not to scare off their prey. Stanford paleoanthropologist Richard Klein calls the study “very intriguing,” although some linguists are skeptical about the common ancestry of the clicks—“the similarities don't overwhelm me,” says Bonny Sands of Northern Arizona University in Flagstaff. Knight's group plans to fill in the picture with studies of other click-speaking groups.

  2. 'Diversity' Benefits Questioned

    A new study by three political scientists suggests that contrary to claims of affirmative-action defenders, racial and ethnic diversity on college campuses does not necessarily contribute to educational quality or to a better social environment.

    The study is bound to stir the pot that is coming to a boil on 1 April as the Supreme Court hears two cases that challenge University of Michigan admissions policies that favor minorities. The university argues that policies fostering diversity enhance education for all.

    In the latest research, Stanley Rothman of Smith College in Northampton, Massachusetts, Seymour Martin Lipset of George Mason University in Fairfax, Virginia, and Neil Nevitte of the University of Toronto analyzed the results of a telephone poll, conducted in the spring of 1999, of about 4000 students, faculty members, and administrators at 140 colleges and universities. They were asked questions about racism and multiculturalism as well as about the general learning environment. The researchers correlated the responses with a proportion of black students at each school and found that as that proportion rose, students of both races expressed less satisfaction with their own educational achievement. Faculty and administrators perceived decreases in educational quality as well. And whites' perceptions of interracial harmony deteriorated. “[T]he predicted positive associations of educational benefits and interracial understanding failed to appear,” the authors report this month in the International Journal of Public Opinion Research. They speculate that “affirmative action places students in academic environments for which they are unsuited, leading to tension and dissatisfaction all around.”

    Defenders of racial preferences in admissions have been relying on a study by psychologist Patricia Gurin of the University of Michigan, Ann Arbor (Science, 22 December 2000, p. 2227), which found that students who were involved in “diverse” activities make gains in intangibles such as listening ability. She says the new study does not undermine her work, which “emphasizes actual experiences students have with diverse peers.” It did not assess the educational or racial climate on campus, she says.

  3. On the Tube

    BBC caveman.


    A new BBC series beginning this month wraps up 3.5 million years of human evolution in four episodes—from Australopithecus afarensis taking its first tentative upright steps in the East African plains to clashes between Neandertals and early Homo sapiens. The series, Walking With Cavemen, intends to “represent a reasonable consensus of different [scientific] views,” says evolutionary biologist Peter Wheeler of John Moores University in Liverpool, U.K, one of more than 100 scientists consulted by the filmmakers. Actors spent up to 5 hours every morning getting made up to play alongside computer-generated prehistoric beasts.

  4. Cloning As Biohazard

    1. Leon Kass
    1. Head of the President's Council on Bioethics at a 19 March Senate hearing on cloning.

    “If we want to prevent the development of anthrax bombs, we do best to block the production of anthrax spores, not just their transfer to a weapons delivery system. Similarly, if we mean to be fully serious about stopping the cloning of human children, we should try to stop the process before it starts … not merely rely on efforts to prevent their transfer to women. …”

  5. The Magic of Materials

    A hammer can shatter a piece of rubber that's been dipped in liquid nitrogen. But when Rice University's Enrique Barrera performs that feat before Houston schoolchildren, he's also shattering the myth that science is only for the elite.

    Barrera with Houston students.


    “For elementary students, our demonstrations are nothing short of magic,” says Barrera, one of 10 educators honored last week with the 2002 Presidential Awards for Science, Mathematics, and Engineering Mentoring. “But I want them to see that there's nothing magical about getting a good education and becoming a scientist.”

    Barrera, a 46-year-old materials scientist, has spent the past 7 years wowing students from high-minority, urban school districts with his Materials Magic Show. The demonstrations range from having young children learn about the molecular behavior of a gas by bouncing tennis balls around a room to introducing high school students to the wonders of nanomaterials.

    Barrera likes to hold up his doctoral diploma and tells students that, with hard work, they can have one, too. “I address the kids as ‘Dr.’ and they love it.” His hope is that the show's magic will linger with his audience all the way through graduate school.

  6. In the Courts

    Dark memory. Psychologist Elizabeth Loftus has spent decades attacking the idea that repressed memories can be recovered. And she has paid a price for it. Last fall, Loftus left the University of Washington (UW), Seattle, for the University of California, Irvine (UCI), after UW officials advised Loftus to take an ethics class in the wake of her study challenging the work of another researcher. Now she's facing a privacy suit by the woman who was the subject of that case study.

    The woman's case, reported by psychologist David Corwin in 1997, involved alleged abuse by her mother. Corwin had interviewed her at age 6 as part of a child-custody dispute and again 11 years later, at which time he helped her recall the alleged abuse, which she had repressed.

    Loftus questioned Corwin's published account and used a private investigator to uncover the subject's identity. After interviewing the woman's relatives, Loftus and a colleague published a 2002 article laying out their doubts.

    Following a complaint by the woman, UW officials barred Loftus from interacting with the woman or her relatives. Loftus, who had grown close to the subject's mother, says she “felt horribly betrayed” by the decree. The UCI offer, she says, relieved her of “having to make secret phone calls.”

  7. Data Points

    Postdoc slump. NSF officials are scratching their heads over the significance of new findings from a 2001 survey showing a 10% decline in the number of postdocs in the life sciences. The surprising drop, from 14,300 to 12,890, reverses a decades-long upward trend in biological and agricultural research, in which a 3- to 5-year postdoc stint has become a prerequisite for an academic post. The overall number of 21,870 postdocs is also down from a 1997 peak of 25,600.

    The biennial NSF survey (nsf.gov/sbe/srs;03-310) captures only the domestically trained slice of the doctoral-level U.S. work force and, thus, understates the total postdoc population. Still, some analysts suggest that the decline reflects the strong economy at the time, whereas others wonder if it might be an early sign that rising stipends are limiting the number of available slots.

  8. Awards

    Timely prizes. French paleontologist Michel Brunet and U.S. astrophysicist John Bahcall have won $1 million each for discoveries that fit the “past” and “future” categories of the Israel-based Dan David Foundation. Brunet, a professor at the University of Poitiers in France, unearthed a hominid skull in Chad thought to be over 6 million years old; Bahcall, who is at the Institute for Advanced Study in Princeton, New Jersey, has spent a career pursuing solar neutrinos. A photographer and a documentary filmmaker shared the “present” prize.

  9. They Said It

    “Sometimes all it takes is putting food in the right place.”

    —Isaac Colbert, MIT graduate dean,

    discussing how to foster interdisciplinary collaborations at an NSF workshop last week on the future of graduate education.