Pigeons can categorise natural and man-made objects

Pigeons can categorise both natural and man-made objects by applying a mechanism similar to the one children use to learn words, scientists have found.
Brains in pigeons may operate in ways not so different from our own, researchers said.
The study from the University of Iowa, US, found that pigeons can categorise and name both natural and human-made objects after the birds categorised 128 photographs into 16 categories, and they did so simultaneously.
"The finding suggests a similarity between how pigeons learn the equivalent of words and the way children do," said Ed Wasserman, UI professor of psychology and corresponding author of the study.

"Unlike prior attempts to teach words to primates, dogs, and parrots, we used neither elaborate shaping methods nor social cues," Wasserman said.
"And our pigeons were trained on all 16 categories simultaneously, a much closer analog of how children learn words and categories," he said.

Wasserman said the pigeon experiment comes from a project in 1988 in which UI researchers discovered pigeons could distinguish among four categories of objects.
This time, the UI researchers used a computerised 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 psychologist Bob McMurray, another author of the study said the research shows the mechanisms by which children learn words might not be unique to humans.
"Children are confronted with an immense task of learning thousands of words without a lot of background knowledge to go on," he said.

"For a long time, people thought that such learning is special to humans. What this research shows is that the mechanisms by which children solve this huge problem may be mechanisms that are shared with many species," he added.