Song Bird

At the same time as Sperry (Roger) was fine-tuning his theory of never development in the early 1960s, a young British biologist, Peter Marler became fascinated with song birds . these birds learned their songs from their fathers. He had noticed, while doing botanical fieldwork, that songbirds of the same species had somewhat different songs (which he called dialects) in different locales. Looking at white-crowned sparrows, he found that young sparrows were eager and able to learn a range of sounds during a brief sensitive period from about 30 to 100 days old. He wondered if he could control what song they learned by what shat song they were exposed to. He isolated young birds during this sensitive period and exposed them to the songs of either their home dialect or an alien dialect. They learned the dialect that they were exposed to. So the dialect they learned was dependent upon their experience. Then he wondered if they could learn the slightly different song of a different species of sparrow if they were exposed to one. He tried alternating the training song with the song of a different sparrow species that were common in their native habitat, but they learned only the song of their own species. So while the song dialect that they learned depended on the song that they exposed to, the variations of the song that they were able to learn were very limited. They were preexisting neural constraints in what they were able to learn. These built-in constraints presented a problem of the blank-slaters ….. en.wikipedia.org/wiki/Tabula_rasa ~ Page 17