Auditory frequency generalization and a failure to find octave generalization in a songbird, the European starling...

Many species of songbirds have absolute pitch perception. They memorize tones when discriminating between sequences and fail to generalize to novel frequency ranges. I examined frequency generalization in starlings (Sturnus vulgaris) that were trained to discriminate between individual frequencies. Starlings were tested for frequency generalization after training on 2- and 3-tone discriminations. There was no evidence for octave generalization, which is a hallmark of human absolute pitch perception. This suggests that avian absolute pitch perception must not be interpreted as identical with that in humans. A control experiment with 1-tone discriminations indicated that the presence of lit response keys affects the shape of the generalization gradients. Lit response keys are a common feature in avian auditory perception experiments, and this control experiment cautions that results may be affected by this seemingly minor procedural change.