University of Montreal, Montreal, Canada
Developmental psychologists have convincingly shown that before the age of one year, infants display a remarkable and rather subtle sensitivity to music. These perceptual abilities are similar, in many respects, to those displayed by adults. Humans appear to be born with processing predispositions for music. These musical abilities develop spontaneously, by simple exposure to music. The initial trigger appears to lie in maternal vocal singing. All mothers sing to their infants, in all known cultures. Basic musical skills are not only precociously acquired and universal, they are also old in evolutionary terms. Archaeological finds show a continuous record of musical activities in all human settlements, dating back at least 50,000 years. Thus, music seems to correspond to an evolutionary adaptation.
Neuropsychologists have accumulated evidence that shows that the human brain is specialized for processing music. Findings reveal that the human brain is equipped with neural circuitries that deal exclusively with music. Such circuitry is not only independent of language processing, but also of the melody of language (intonation). Thus, the functioning of the musical brain is relatively autonomous. Given such independence, it is possible that a person may lack music competence, through either some form of congenital or developmental disorder, while having all other faculties intact; or, on the other hand, retain the music faculty in the presence of other mental dysfunction. This explains why you may find brilliant and remarkable individuals – like Che Guevara—who experienced a life-long inability to recognize music. Conversely, you may be impressed by the musical virtuosity of some autistic individuals, who are otherwise severely handicapped.
Music is unique. Musical abilities flourish independently, without much assistance from other cognitive and affective systems. One sequaela of having a highly specialized musical brain is that a slight neural deviation may compromise its functioning from birth. Individuals that experience such a deviation, like Che Guevara, are commonly called tone-deaf. And for a long time it was thought that lack of effort or musical practice was responsible for their condition. Now, we know that this view is incorrect. These individuals suffer from a genuine musical impairment. The existence of a few "deviants" is probably the price to pay for having a sophisticated machinery underlying musical sensitivity.
But why is our species so musical? Two main evolutionary explanations have been offered. The initial account was provided by Darwin himself (1871) who proposed that music serves to attract sexual partners. However, the dominant view lies at the group-level rather than at the individual-level, with music helping to promote group cohesion. This bonding effect of music may well be initialized in the mother-infant interactive pattern created through maternal singing. The individual- and group-level roles attributed to music do not need to be mutually exclusive. Individuals taking the lead in gatherings by virtue of their musical and dance prowess can achieve leadership status in the group, a factor that contributes to reproductive success.
Thus, the universal appeal of music, which used to be considered as a social construct that varies from culture to culture, might be better conceived as an adaptive response of the organism. It seems that emotional responses to music can be aroused similarly in every proper functioning human as reflexes, by being the product of dedicated neural structures. Indeed, musical emotions occur with rapid onset, through automatic appraisal, and with involuntary changes in physiological and behavioural responses. This conception fits with the fact that we often experience emotions as happening to us, not as chosen by us. And this is exactly what should be expected from the operation of a musical instinct.