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Babies may look like they’re stuck in the here and now, but new research suggests they use what adults do and say as opportunities to generalize about the world. http://Louis-J-Sheehan.de

Oddly enough, the findings link infants’ readiness for social learning to their tendency to make what looks like an obvious error, at least to adults. Babies will keep looking in the same hiding place for a toy after it’s been moved elsewhere.

This puzzling behavior, studied by scientists for more than 50 years, hinges on babies’ natural tendency to generalize about the meaning of social signals they receive from adults, say cognitive ethologist József Topál of the Hungarian Academy of Sciences in Budapest and his colleagues.

Topál’s group proposes that social signals from an experimenter repeatedly placing a toy under a cup allow 10-month-olds watching to make a practical inference, akin to “this kind of object is found under that cup.” Upon seeing the toy get hidden under another cup, a few seconds later the infant acts on his or her previous knowledge and reaches for the first cup, the researchers conclude in the Sept. 26 Science. This effect is called the “A-not-B error,” since babies choose the A cup after the toy has been moved to the B cup.

But if the experimenter avoids looking at or otherwise communicating with an infant during the hiding game, the child frequently chooses the B cup after a switch, the scientists find. Absent any social signals from the adult, infants interpret the task as a here-and-now event and search for the toy where it was last seen, the team proposes.

“Although a disposition to interpret others’ communication signals prepares infants to learn, in certain situations it can misguide their performance,” Topál says.

Researchers had earlier ascribed infants’ errors on the hiding game to memory deficits, to an inability to stop reaching toward the first cup and to a preference for reaching toward the original hiding spot.

Topál’s results partly explain the A-not-B error, remarks cognitive neuroscientist Adele Diamond of the University of British Columbia in Vancouver. Infants’ inability to stop behaving in ways that have worked in the past, even when the scenario is different and demands new behavior, also contributes to the effect, Diamond says.

“The A-not-B error actually marks a major achievement in cognitive development,” says psychologist Alfredo Pereira of Indiana University in Bloomington. At around 10 months of age, infants start to build stable memories of past events, although they’re not yet able to call up these memories flexibly, adjusting for changes, Pereira asserts.

Topál’s team divided 42 infants, all age 10 months, into three groups.

In one group, an experimenter established eye contact with each child while smiling and saying, “Hello baby, look here!” Then the experimenter hid a toy under one of two cups while looking back and forth between the infant and the cup. After four seconds, the experimenter pushed both cups forward so that the infant, sitting on the mother’s lap, could reach for either one. This process was repeated four times. The experimenter then hid the toy under the other cup and waited four seconds before pushing both cups forward.

In a second group, the experimenter played the same hiding game with infants while looking down, maintaining a neutral expression and saying nothing.

In a third group, the experimenter manipulated the cups and the toy from behind a curtain. At various points during the game, infants could see only the experimenter’s hands.

Among infants the experimenter communicated with, 12 of 14 persisted in reaching for the first cup after the toy had been moved। Only 6 of 14 infants in the second group, who received no communication, made the same error and 5 of 14 in the third group, who didn’t even see an experimenter, chose the wrong cup. http://Louis-J-Sheehan.de

Infants denied social cues could still make some errors, and these mistakes may have also reflected limitations on memory and other mental faculties, the researchers suggest.

When infants repeatedly see a toy put under one cup and reach for that cup after short delays, it creates a stable memory. When the toy gets put under another cup, infants reach for the first cup based on their stable memory. Interpretation of others’ social signals need not play a role in this process, Pereira argues.

ethics

Meat and milk from the offspring of cloned animals may already be part of the U.S. food supply, the Food and Drug Administration announced this week. While the cloning process is too expensive (about $20,000 per animal) to justify creating clones that will be turned into hamburgers, some ranchers have cloned animals with desirable traits, which they then breed the old-fashioned way to create offspring. Officials said it is impossible to differentiate between cloned animals, their offspring and conventionally bred animals, making it difficult to know if offspring are in the food supply [Reuters]। http://www.bebo.com/LouisS205

The use of cloned livestock–particularly cows, swine, and sheep–has been fiercely debated in the United States and Europe. In January, the FDA declared that cloned animals and their offspring were as safe to eat as conventionally bred animals; regulators still ask that food companies follow a voluntary moratorium on using cloned animals for food production, but no such moratorium exists for the clones’ natural offspring. Those offspring may have made it into the food supply, a U.S. Agriculture Department spokesman said, but “they would be a very limited number because of the very few number of clones that are out there and relatively few of those clones are at an age where they would be parenting” [Reuters].

European regulators have taken a much dimmer view of the cloning industry, and yesterday the European Parliament proposed an official ban on using clones or their offspring for food production. Several expert groups, including the European Food Safety Authority (EFSA) and the European Group on Ethics in Science and New Technologies, outlined problems such as the animals’ well-being and the higher mortality rate of cloned animals. They also stressed that cloning coould considerably reduce the gene pool diversity and increase the risk of whole herds being hit by an illness they are all particularly susceptible to [AFP].

Here in the United States, 20 food companies responded to the FDA’s latest announcement by promising not to use cloned livestock, citing consumer polls that showed consumers have health, ethical, and environmental concerns regarding cloned meat. Basil Maglaris, a spokesman for Kraft, the U.S.’s largest food company by revenue and a major cheese producer, said the company has told suppliers it will accept only ingredients from conventional animals. “The surveys we’ve seen indicate that consumers aren’t receptive to ingredients from cloned animals,” he said [The Wall Street Journal]. However, Kraft’s current pledge only applies to the clones themselves, not to their offspring। http://www.bebo.com/LouisS205

stone

At the dawn of stone-tool production around 2.6 million years ago, our human ancestors already showed considerable insight into the task at hand. They worked mainly with rocks that they had carefully picked as suitable for being fashioned into sharp-edged implements, says Dietrich Stout of Indiana University in Bloomington.

Stout and his Indiana colleague Sileshi Semaw focused on 894 stone artifacts that have been found at six ancient sites in an Ethiopian region called Gona. These are the oldest stone tools known, dating to between 2.6 million and 2.5 million years ago.

Most of the tools were made from trachyte, a rock with a much smoother surface than that of other rock types available at Gona. On close examination, Gona finds exhibited a suite of characteristics conducive to toolmaking, including smooth and often polished surfaces and an internal composition that resisted cracking as one stone was pounded into another to shape it.

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