SCIENCE NOTEBOOK

Watchful Eyes Increase Generosity

Charities may want to add a pair of blinking eyes to their Web-based pleas for donations. That's one implication of new research into the evolutionary roots of generosity.

Researchers have long known that people tend to donate more liberally when they are being watched. The evolutionary explanation is one of self-interest: A generous act may pay off later, while selfishness can come back to bite.

But how hard-wired is that reaction? Humans are known to be acutely aware of when they are being watched -- the result of an involuntary brain response to other eyeballs that offers obvious survival benefits. Is that gaze-detector so strong that even a robot can shame a person into giving more?

To find out, Terence Burnham of Harvard University and Brian Hare of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, enlisted 96 Harvard Business School students in an experiment. In each round, four students were given a set of tokens and told that they could either cash them out at the end of the exercise or donate them to the group, in which case all four would get a fraction of the tokens' value -- an option that gave each person less but distributed the money more evenly. They could not talk or strategize.

The students shared about 30 percent more of their tokens when an image of Kismet, a wide-eyed robot developed at the Massachusetts Institute of Technology, appeared on their computer screens while they decided.

The fact that donations jumped in response to a pair of eyes that obviously had no capacity to watch or judge them suggests that humans automatically behave in more socially conscious ways when the brain detects a visual pattern resembling a gaze, the team concludes in the June issue of Human Nature, released this month.

-- Rick Weiss

Bees May Help Elephants Survive

Could bees be used as the equivalent of scarecrows to scare off elephants in Africa?

One of the reasons elephant populations are being threatened is that they are increasingly coming into contact with humans, who sometimes kill the animals when they trample or eat crops. Knowing that previous research had indicated that elephants tend to stay away from bees, researchers studied whether the sound of bees could be used to keep them away from areas where they may run into trouble.

Lucy E. King of the University of Oxford and her colleagues tested the response of several elephant families in Kenya to the digitally recorded sound of angry African bees, played from inside a fake tree trunk. Sixteen of the 17 families left their resting places within 80 seconds of hearing the bee sounds, and half did so within 10 seconds. Among elephants hearing natural white noise, none moved after 10 seconds, and only four families moved after 80 seconds. By the end of four minutes of bee sounds, only one family had failed to move, whereas eight families hearing the neutral sound had not moved.

"We weren't surprised they responded to the threatening sound of disturbed bees, as elephants are intelligent animals that are intimately aware of their surroundings, but we were surprised at how quickly they responded to the sounds by running away," said King, who reported the findings in the Oct. 9 issue of Current Biology.

"If we could use bees to reduce elephant crop raiding and tree destruction while at the same time enhancing local income through the sale of honey, this could be a significant and valuable step towards sustainable human-elephant coexistence," she said.

-- Rob Stein

Biofuels' Possible Drawbacks

The nation's growing emphasis on using biofuels to promote energy independence could have an adverse effect on regional water supplies and water quality, according to a report from the National Research Council, part of the National Academies.

The drive to produce more corn for ethanol production -- encouraged by rising oil prices and federal subsidies -- may lead to growing the crop in regions with little agriculture, including dry areas, the council found. Irrigation demands would compete with other uses of water, such as drinking, hydropower, fish habitat and recreation. Moreover, the quality of groundwater, rivers and coastal waters could be worsened by pesticides and fertilizer used to produce biofuel crops, the report found. Rain washes the pesticides and fertilizer downstream, where they can contribute to increased nitrogen levels that threaten aquatic life in areas such as the Chesapeake Bay.

"Nutrient pollution can have significant impacts on water quality," the report said.

Bob Dinneen, president of the Renewable Fuels Association, an industry group, acknowledged that water quality and availability are potential concerns but said technology advances will help: "Better efficiencies at today's ethanol refineries are reducing water use, improving water recycling methods and utilizing wastewater supplies to further lessen the impact, if any."

-- Christopher Lee