In observing the dogs' behavior, the researchers looked for signs of aggression, attention-seeking and interest in their owner or the objects. The test was designed to help the researchers determine if the dogs felt an emotion similar to jealousy, or if they were just generally annoyed when they lost their owners' attention.
The dogs demonstrated more jealous behaviors when their owner focused on the stuffed dog than when their owner paid attention to the other objects, the study found. These behaviors included trying to come between their owner and the stuffed dog, pushing their owner and snapping when the owners displayed affection toward the stuffed dog.
The researchers concluded a form of primitive jealousy that exists in babies may also exist in at least one other social animal: dogs. This emotion, the study's authors suggested, may have evolved to help infants compete for resources from their parents, including food, attention, love and care.
The ASPCA provides more information on dog behavior.
SOURCE: Public Library of Science, news release, July 23, 2014; University of California, San Diego, news release, July 23, 2014
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