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

Von: Kevin Austin via cec-conference

Datum: Tue, 12 Jul 2016

Betreff: [cec-c] Songbirds use spectral shape, not pitch, for sound

pattern recognition

PNAS vol. 113 no. 6> Micah R. Bregman, 1666–1671, doi:

10.1073/pnas.1515380113

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

1. Micah R. Bregman

2. Aniruddh D. Patel

and

3. Timothy Q. Gentner

Abstract

Significance

Past work characterizes songbirds as having a strong bias to rely on

absolute pitch for the recognition of tone sequences. In a series of

behavioral experiments, we find that the human percepts of both pitch

and timbre are poor descriptions of the perceptual cues used by birds

for melody recognition. We suggest instead that auditory sequence

recognition in some species reflects more direct perception of acoustic

spectral shape. Signals that preserve this shape, even in the absence of

pitch, allow for generalization of learned patterns.

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.