Spierings, M. 1, 2 & ten Cate, C. . 1, 2
1 Behavioural Biology, Institute of Biology Leiden (IBL), Leiden University Leiden, P.O. Box 9505, 2300 RA, The Netherlands
2 Leiden Institute for Brain and Cognition (LIBC), Leiden University Leiden, P.O. Box 9600, 2300 RC, The Netherlands
The ability to abstract a grammar rule that underlies strings of seemingly meaningless sounds is an important aspect of language learning. This ability is a core mechanism underlying the language faculty, but might not be specific to language learning or even to humans . In this study we tested a songbird species (zebra finches) and a parrot (budgerigars) on their rule learning abilities. Subjects were trained to discriminate between sequences of song elements that followed either an XYX or an XXY structure. After this discrimination was acquired, each subject received a number of test sounds (intermixed with training sounds) that followed the same structural rules, but consisted of new elements or new combinations of known elements. The budgerigars generalized their discrimination to sequences consisting of new sounds, so formed an abstract representation of the structure of the training sequences. Zebra finches followed a positional learning strategy, where the sound sequences with known elements were categorized in accordance with the positional similarity to the training sequences. This implicates that although the ability to abstract and generalize structural rules is not readily found in the animal kingdom, there are species that share this mechanism with humans.