Pigeons' brains are equivalent to that of toddlers, according to the study by researchers at University of Iowa (UI). The study finding suggests that pigeons can categorize and name several natural and man-made objects. These birds simultaneously categorized 128 photographs into 16 categories.
Professor Ed Wasserman said, "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. Our research on categorization in pigeons suggests that those similarities may even extend to how children learn words. 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."
During this study, 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 4 new photos from each of the 16 categories.
The study appears online in the journal Cognition.