# Random Samples

Science  12 Jul 2002:
Vol. 297, Issue 5579, pp. 189
1. # In Me I Trust

People apparently really do like seeing themselves in others. A new study reveals that players bargaining for money in games are more likely to trust faces that remind them of their own.

Animal studies have revealed that many critters favor conspecifics that resemble them, a phenomenon called kin selection. “Since relatives share your DNA, it's another way of making sure your genes survive,” explains evolutionary psychologist Lisa DeBruine of McMaster University in Hamilton, Ontario.

To see if humans do the same thing, DeBruine set up two-person games in which subjects, playing via computer, either divide a few dollars equally or trust the other player to divide a larger sum. In each “bargaining round,” a subject interacted with one of 16 possible partners, whose faces were shown on the monitor. Some of these faces were totally unfamiliar; others were “morphs,” made by combining photos of the 24 players themselves with photos of strangers.

In a paper in the 7 July issue of the Proceedings of the Royal Society, DeBruine reports that the subjects trusted faces resembling their own more than two times out of three, whereas they trusted unfamiliar faces only half the time. DeBruine tried morphs resembling celebrities such as Ben Affleck to see if mere familiarity inspired confidence, but it was only the self- resemblance that did it.

Social psychologist Gene Burnstein of the University of Michigan, Ann Arbor, calls the work “a very nice demonstration of an important psychological mechanism. … It would be interesting to know what happens when similarity reaches the point at which the observer begins to become aware of it.”

2. # Pet Cancer Registry

A top killer of people, cancer also takes the lives of many cats and dogs. Now researchers in New York are setting up a pet tumor registry to probe possible links between environmental agents and cancer in people and pets.

The registry will complement a $30 million NIH study begun in 1993 of unusually high breast cancer rates on Long Island. As part of that study, researchers have created maps of human cancer cases and possible carcinogen sources such as factories and toxic waste dumps. A team at Cornell University now has$20,000 from the state legislature for a pilot project compiling data from pet tumor biopsies in Long Island's Nassau County, one area with suspected high cancer rates. Tompkins County in upstate New York might be used as a control. The registry will record tumors in dogs and cats and owners' zip codes to see if cancer hot spots for pets match up with where human risks are higher, says Cornell veterinary oncologist Rodney L. Page. The investigators also hope to get funds to collect blood, urine, and tissue samples.

Pets should help fill in the cancer picture, says Page: They develop tumors sooner than humans, tend to have higher exposures to pesticides and polluted water, and don't smoke. Pet cancer studies have yielded useful insights in the past, he adds. For example, a higher rate of testicular cancer in military dogs exposed to dioxin-laced Agent Orange in Vietnam led researchers to find a similar but more tentative link in humans.

Debbie Winn, an epidemiologist at the National Cancer Institute in Bethesda, Maryland, says that such a registry “can be a useful idea,” although she says it would need to catch every single case to be especially useful.

3. # Sun Burp

The sun jumped the gun on Independence Day fireworks, belching out a massive curling cloud of flaming gas more than 30 times Earth's diameter on 1 July. Called a solar prominence, the gas is suspended by loops of magnetic field. This image was captured by the SOHO satellite.

4. # New Stem Cell Ethics Initiative

A bioethicist and a stem cell biologist at Johns Hopkins University in Baltimore have teamed up to spearhead multidisciplinary scrutiny of “second-generation” ethical questions surrounding stem cell research.

Researcher John Gearhart, who has developed a stem cell line, and Ruth Faden, director of the university's bioethics institute, have an initial 2-year grant of \$300,000 from the Greenwall Foundation and are expecting to get more money in the future from other sources.

Faden says that in the coming months a group of scientists, lawyers, and bioethicists will meet periodically to chew over the first topic on their agenda: criteria that stem cells should be evaluated against before they become therapies. “We know very little about the characteristics of the sources” (the embryo donors) of stem cell lines currently available for research, she says, and the need for this information has to be balanced against sources' privacy needs. The group will also explore issues surrounding the genetic diversity of the cell lines, which will be of particular significance if people are going to be treated with mass-produced cells.