(In peer-review)
Grapheme-phoneme correspondence decoding in an Umbrella cockatoo (Cacatua alba)
Cunha, J., Hirskyj-Douglas, I., Kleinberger, R., Clubb, S., & Perry, L., (under review). Grapheme-phoneme correspondence decoding in an Umbrella cockatoo (Cacatua alba).
Abstract: Symbolic representation is the complex cognitive process of learning to use a symbol, such as an image, word, or sign, to stand for something else. A variety of non-human animals, including several primate and avian species, can engage in symbolic representation. One particularly complex form of symbol representation is the ability to learn associations between orthographic symbols and speech sounds, in which the symbols combine and recombine to change what is being symbolized. To date, there is no evidence that non-human animals can learn this form of symbolic representation, also called grapheme-phoneme correspondence. Here, we ask whether an Umbrella cockatoo (Cacatua alba) can learn grapheme-phoneme correspondence to recognize previously unseen, unheard words. The cockatoo was trained with systematic phonics instruction and then tested under blind conditions in a two-alternative-forced-choice task to correctly select the index card with a written word consistent with an English spoken word. The cockatoo’s accuracy (M= 71%) was significantly higher than chance, and higher than a control group of English-speaking human adults who watched muted videos of her test trials to guess the correct card. Accuracy was negatively associated with the number of overlapping letters shared between the two written words—the more common letters there were to appear in both words, the less accurate the cockatoo was. This exploratory analysis suggests that the cockatoo’s errors were not random, but related to properties of grapheme-phoneme correspondence. Together, these results indicate that cockatoos may have the ability to learn grapheme-phoneme correspondences.