This release is also available in German.
Dog owners convinced of their pets' grasp of human language may be validated, at least in part, by new research on the word-learning abilities of a German family's Border collie. Scientists who studied a dog with an approximately 200-word "vocabulary" suggest that some aspects of speech comprehension evolved earlier than, and independent from, human speech.
This research appears in the 11 June 2004 issue of the journal Science, published by AAAS, the nonprofit science society.
"You don't have to be able to talk to understand a lot," said senior Science author Julia Fischer from Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany.
Rico, the nearly nine-year-old Border collie, can learn the names of unfamiliar toys after just one exposure to the new word-toy combination. The scientists equate the dog's apparent learning to a process seen in human language acquisition called "fast mapping." The fast mapping abilities of children allow them to form quick and rough hypotheses about the meaning of a new word after a single exposure.
"Such fast, one-trial learning in dogs is remarkable. This ability suggests that the brain structures that support this kind of learning are not unique to humans, and may have formed the evolutionary basis of some of the advanced language abilities of humans," said Katrina Kelner, Science's deputy editor for life sciences.
The German team first verified Rico's 200-word "vocabulary." In a series of controlled experiments, Rico correctly retrieved, by name, a total of 37 out of 40 items randomly chosen from his toy collection. The authors write that Rico's "vocabulary size" is comparable to that of language-trained apes, dolphins, sea lions and parrots.
Next, the researchers tested Rico's ability to learn new words through fast mapping. Fischer's team placed a new toy among seven familiar toys. In a separate room, the owner asked Rico to fetch the new item, using a name the Border collie had never heard before.
Rico correctly retrieved a new item in seven of ten sessions. He apparently appreciates, as young children do, that new words tend to refer to objects that do not already have names. After a month without access to these target toys, Rico retrieved them, upon request, from groups of four familiar and four completely novel toys in three out of six sessions. His retrieval rate is comparable to the performance of three-year-old toddlers, according to the authors.
"For psychologists, dogs may be the new chimpanzees," writes Paul Bloom from Yale University in New Haven, CT, in an accompanying "Perspective" article in Science.
Scientists around the world are currently studying how chimpanzees learn language and communicate.
The authors do not claim that Rico and children have an equally rich understanding of words. They do show, however, that Rico can make the link between objects and sounds.
"This is a crucial step that allows an animal to figure things out in the environment," Fischer explained.
Fischer's team is now investigating Rico's ability to understand entire phrases, such as requests for Rico to put toys in boxes, or to bring them to certain people.
Fischer noted that people should not take this study as a reason to go out and get a Border collie as a novelty.
"Border collies are working dogs," Fischer said. "If they were humans, we'd call them workaholics. They are high-maintenance, professional dogs that need at least four or five hours of attention a day."
Juliane Kaminski, Josep Call and Julia Fischer are at the Department of Developmental and Comparative Psychology, Max Planck Institute for Evolutionary Anthropology, in Leipzig, Germany.
Funding for this research was provided in part by Deutsche Forschungsgemeinschaft.
Video available at http://media.eurekalert.org/scipub/1097856s2.mov.
The video clip shows the very first session of the identification task, in which a novel item is requested by using a novel name. Rico is first instructed to bring two familiar items; first the "tyrex" (the blue dinosaur), and next the "weihnachtsmann" (the little red doll). Subsequently, a novel word ("sirikid") is used to ask for the novel item, the white bunny.
Video courtesy of Julia Fischer
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