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Science Notes Animal behavior, psychiatry

Dogs develop preferences for scent prenatally

Dogs are famous for their sense of smell. But only now, with the publication of a peculiar experiment, can scientists say with assurance that dogs are already sniffing and smelling while still in the womb.

Deborah Wells and Peter Hepper of the canine behavior center at Queen's University of Belfast in Northern Ireland knew that "prenatal chemosensory learning" - the ability to differentiate among smells before birth and develop preferences that persist afterward - had already been documented in other animals. Some experts have theorized that prenatal olfactory learning helps newborns recognize their mothers and may help prompt suckling behavior.

Yet the phenomenon had never been tested in dogs, despite their reputations as world-class sniffers.

The researchers enrolled 22 pregnant dogs in a series of studies in which some were fed food spiked with aniseed. Immediately after birth, pups were taken briefly to a quiet area and presented with a pair of cotton swabs - one wetted with a trace of aniseed and the other with distilled water.

Pups from mothers fed aniseed showed a strong preference for the aniseed swabs.

Ultrasound studies have documented that fetal dogs start making breathing movements at least two weeks before birth, apparently taking in amniotic fluid through their noses and mouths as "practice" for doing so with air.

The new results, the researchers hypothesize in the journal Animal Behavior, show that during this period, smell receptors in the nose are already functioning.

- Washington Post


Compulsive shopping afflicts men, too

Men are as likely as women to be compulsive buyers, a condition that affects about one in 20 adults in the United States, according to Lorrin Koran, an emeritus professor of psychiatry at Stanford University's medical school.

Koran and his colleagues surveyed 2,513 adults in 2004 and found that 6 percent of women and 5.5 percent of men exhibited symptoms of hard-core compulsive shopping: irresistible and often senseless impulses to buy that they felt largely powerless to resist.

"Compared with other respondents, compulsive buyers were younger, and a greater proportion reported incomes under $50,000 and were more than four times less likely to pay off credit card balances in full," Koran and his colleagues reported in the American Journal of Psychiatry.

- Washington Post

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