Songbirds use spectral shape, not pitch, for sound pattern recognition

Abstract

Humans easily recognize "transposed" musical melodies shifted up or down in log frequency. Surprisingly, songbirds seem to lack this capacity, although they can learn to recognize human melodies and use complex acoustic sequences for communication. Decades of research have led to the widespread belief that songbirds, unlike humans, are strongly biased to use absolute pitch (AP) in melody recognition. This work relies almost exclusively on acoustically simple stimuli that may belie sensitivities to more complex spectral features. Here, we investigate melody recognition in a species of songbird, the European Starling (Sturnus vulgaris), using tone sequences that vary in both pitch and timbre. We find that small manipulations altering either pitch or timbre independently can drive melody recognition to chance, suggesting that both percepts are poor descriptors of the perceptual cues used by birds for this task. Instead we show that melody recognition can generalize even in the absence of pitch, as long as the spectral shapes of the constituent tones are preserved. These results challenge conventional views regarding the use of pitch cues in nonhuman auditory sequence recognition.absolute pitch | songbirds | comparative cognition | pitch processing | pattern perception

Preface to the Special Issue on Animal Music Perception

“…In fact, in a follow-up study with humans and chickadees, we found that chickadees did not respond to novel timbres based on the pitch information with which they had been trained (Hoeschele, Cook, Guillette, Hahn, & Sturdy, 2014). Similar results have also been found in starlings (Bregman, Patel, & Gentner, 2016).…”

“…A similar result was found in European starlings: They also did not do well on traditional laboratory relative pitch tasks but readily recognized transposed versions of their own song (Bregman, Patel, & Gentner, 2012). However, it is likely that they were not directly using pitch in this task but spectral shape information from which both pitch and timbre are derived (Bregman et al, 2016).…”

Chickadee songs provide hidden clues to singers’ locations

“…Recent experimental studies show that birds are more sensitive to similarities and differences in spectral shape than was previously assumed (Bregman et al, 2016;Hoeschele et al, 2014). Chickadees, in particular, appear to find relative differences in the amplitudes of frequencies produced within fee-bee songs to be highly salient (Hoeschele et al, 2014).…”

“…Humans have been tested on their ability to detect differences in the intensities of two simultaneously presented tones centered at different frequencies, however (Dai & Green, 1992;Feth & O'Malley, 1977;Versfeld & Houtsma, 1995). Such distinctions can be viewed as a special case of profile analysis (Green, 1987), which is closely related to auditory discrimination of spectral shape (Bernstein & Green, 1988;Bregman, Patel, & Gentner, 2016;Langemann, Zokoll, & Klump, 2005). Profile analysis involves detecting an absolute increment in the amplitude of one tonal signal among a background of other tonal signals.…”

Consonance Processing in the Absence of Relevant Experience: Evidence from Nonhuman Animals

“…As has been shown by Bregman, Patel, and Gentner (2016), birds (European starlings) rely on acoustic cues other than absolute pitch to generalize to novel stimuli. Instead of using the absolute frequency of the sounds, they prioritize their spectral shape.…”