People may say birds are brainless, but it turns out that pigeons' brains are equivalent to that of toddlers''.
According to the study by University of Iowa professor Ed Wasserman, the finding suggests a pigeons can categorize and name both natural and manmade objects-and not just a few objects. These birds categorized 128 photographs into 16 categories, and they did so simultaneously.
Wasserman said that unlike prior attempts to teach words to primates, dogs, and parrots, they used neither elaborate shaping methods nor social cues. And the pigeons were trained on all 16 categories simultaneously, a much closer analog of how children learn words and categories.
Their research on categorization in pigeons suggests that those similarities may even extend to how children learn words.
Wasserman said that the pigeon experiment comes from a project published in 1988 and featured in The New York Times in which UI researchers discovered pigeons could distinguish among four categories of objects.
This time, the UI researchers used a computerized version of the "name game" in which three pigeons were shown 128 black-and-white photos of objects from 16 basic categories: baby, bottle, cake, car, cracker, dog, duck, fish, flower, hat, key, pen, phone, plan, shoe, tree. They then had to peck on one of two different symbols: the correct one for that photo and an incorrect one that was randomly chosen from one of the remaining 15 categories. The pigeons not only succeeded in learning the task, but they reliably transferred the learning to four new photos from each of the 16 categories.
UI researchers said their expanded experiment represents the first purely associative animal model that captures an essential ingredient of word learning-the many-to-many mapping between stimuli and responses.
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Wasserman acknowledges the recent pigeon study is not a direct analogue of word learning in children and more work needs to be done. Nonetheless, the model used in the study could lead to a better understanding of the associative principles involved in children's word learning.
The study is published online in the journal Cognition.