The Origins of Music: Preface - Preface

This indicates that all of the phrase types we tested,not just whistles,can

be recognized by naive fledglings,even though the phrases are divorced

from normal syntax (Whaling et al.1997).Although avian vocal signals

are greatly simplified compared with human language,these results par-

allel findings of studies of language recognition in human infants.Human

infants can recognize the phonemes of all human languages,providing

them with the capacity to learn any language.They are even able to dis-

criminate phonemes not used in their local language,although this sen-

sitivity disappears once they begin to speak (Eimas,Miller,and Jusczyk

1987;Kuhl 1995).

It is possible that,rather than relying on note structure,young birds

use tonal or temporal qualities to identify songs of their own species.

We have begun to test songs that are altered in pitch.White-crowned

sparrow fledglings tested in the laboratory did not treat those songs dif-

ferently from unaltered songs until the pitch was shifted more than six

standard deviations away from the dialect mean (Whaling,unpublished

observations).Adult sparrows of other species can distinguish shifts in

pitch that are two or three standard deviations from the mean (Nelson

1989),suggesting that the fledglings may be more forgiving of pitch

manipulations than adult birds.

The Neurobiology of Learning Preferences

Armed with this information on the abilities of inexperienced fledglings

to recognize song,Allison Doupe and her colleagues undertook an

examination of the neural basis of innate discrimination by examining

the neurons in and around the song control nucleus HVC.HVC contains

both motor neurons for song production and auditory neurons for

song perception.These auditory neurons fire when the adult bird

hears a taperecording of himself singing (Margoliash 1986),a response

that is acquired as the result of learning to sing (Volman 1993).

Furthermore,auditory neurons were found in an area near HVC that

are more responsive to the songs of one’s own species than to foreign

songs,as revealed by patterns of gene activation (Mello,Vicario,and

Clayton 1992).We wondered whether fledglings would also have neurons

that respond most to the songs of their own species,even though they

had not yet heard those songs,much less learned to sing them.Would

these brain areas contain neurons whose properties could explain how

young birds recognize and choose to learn the songs of their own

species?

Extracellular recordings were made from neurons in HVC and the sur-

rounding neostriatum by lowering a recording electrode into the brain

71 The Neural Basis of Song Learning in Birds

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