Step aside lizards, looks like we have a new animal overlord. A recent study published in Proceedings of the National Academy of Sciences found that pigeons can be trained to understand some words, sort of.
Scientists trained the four smartest pigeons they could find to tell the difference between four-letter words and nonwords, and identify when a word’s letters were transposed (like “very” vs. “vrey”).
The authors of the study measured the pigeons’ performance against both baboons and humans, finding that their ability to differentiate between anagrams “is actually more comparable to that of literate humans than the baboons’ performance.”
The method scientists use to determine whether the pigeon could differentiate between words and nonwords is pretty basic. They first trained the birds to eat from a hopper bird feeder. “After hopper training, an autoshaping procedure was used until subjects were consistently pecking stimuli presented in any of the three apertures,” the authors write. Below is a video from a 2007 study that demonstrates an autoshaping procedure, which is a commonly used Pavlovian conditioning technique.
After the pigeons were conditioned with the autoshaping procedure, the scientists began to present word and nonword stimuli through the aperture of the hopper. “When a word was presented in the centre aperture, the correct response was to peck the word,” the study’s authors write. They also displayed a “star stimulus” to the pigeons either above or below the centre aperture, randomizing its location in each trial. When a pigeon was presented with a nonword, they were supposed to peck the star stimulus.
Pigeons were rewarded for their correct responses with wheat. “A correction procedure was used throughout training, such that after an incorrect response, the trial was repeated until the subject made the correct response,” the scientists explain.
The pigeons, by the end of the study, learned to differentiate between 26 and 58 words. The authors of the study then concluded “visual systems organisationally distinct from the primate visual system can also be...recycled to process the visual word form.”