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1.5.1
DARWINIAN
EVOLUTION
AND ADAPTATIONS
(INCLUDING
MUSIC)
I don’t like nature. It’s big plants eating little plants, small fish being
eaten by big fish, big animals eating each other ... It’s like an enormous
restaurant.
—WOODY ALLEN (Love and Death)
Many consider Charles Darwin one of the three greatest scientists
of all time, in the company of Newton and Einstein. Darwin and
Alfred Russell Wallace independently came up with the insight now
called Darwinian evolution. Darwin wrote a number of landmark
books identifying and describing natural selection, sexual selection,
and other aspects of evolution.
Darwinian
evolution is the most important theory in all of biology. Voluminous evidence
from modern science shows that Darwin got it right, despite having no knowledge
of DNA or genes. Darwin discovered that life evolves in distinct lines, with
each species on its own individual twig of an ever-widening bush, each species descended from
a common ancestor, but destined never to meet. (However, at the bacteria level
some evidence indicates “gene-swapping” goes on between unrelated organisms.)
Humans did not “descend from apes,” and chimpanzees will never evolve into
humans.
Darwin came under fierce attack for pointing out (correctly, it
turns out) that humankind is merely one of millions of species that
evolved from earlier life forms. Moreover, nothing creative or
directional goes on in evolution. No ultimate goal exists in the
evolution of any species. Homo sapiens does not represent the
culmination of anything and is not evolving towards anything.
It’s
an interesting paradox that humans, with dazzling cognition and insight about
everything from Einsteinian relativity to genetics to artistic expression, are
clearly unlike any other species on the planet—and yet humans evolved by exactly
the same processes as all other species on the planet and carry the same genes
as the humblest of them.
Darwinian evolution causes the emergence of adaptations such
as bipedalism, music, and language in two ways: natural selection
and sexual selection.
1. How Natural Selection Works
All living things compete to survive and pass on their genes. In a
given species, each individual differs slightly from all the other
individuals. Therefore, in the prevailing environmental conditions, the
ability to survive and procreate varies from individual to individual.
This variability means some individuals thrive better than others under the same
environmental conditions. Those that do best—the winners in the evolutionary
struggle for resources and opportunities to reproduce—are thus “naturally
selected” to pass on their genes to the next generation. Those individuals that
do not fare well in the same environment do not pass on their genes.
2. How Sexual Selection Works
Although some species do not reproduce sexually, most do.
Members of species that reproduce sexually compete with each
other to mate with individuals of the opposite sex. Individuals of both
sexes vary in their attractiveness and availability as potential mates.
This variability means some individuals are more successful than others in
mating and procreating, and are thus “sexually selected” to pass on their genes.
Those individuals that fail to mate do not pass on their genes.
Woody
Allen’s observation that the world is an enormous, chaotic restaurant is bang
on. All animals, including humans, survive and evolve by eating plants or other
animals or both. Species evolve defences to keep from getting eaten. Other
species evolve ways to get around those defences, which triggers the evolution
of more elaborate defences, and so on—an evolutionary arms race. “Nature,
red in tooth and claw,” as Tennyson put it.
The Naturalistic Fallacy
The naturalistic fallacy goes like this:
whatever happens in the natural world, well, that’s the way it ought to be.
The problem is, it doesn’t follow logically
that, just because something happens in nature, it’s a Good Thing—that its
moral value is somehow asserted. Belief that “natural = good” is called the naturalistic fallacy. This fallacy led to
social Darwinism,
discussed earlier.
Nature is utterly mindless and blindly
indifferent. Heart defects are natural. So is cancer. So is malaria. Nature is
by far the world’s greatest bioterrorist.
We humans have “natural” inclinations to lash
out violently against those we perceive as doing us harm. Fortunately, humans
also have natural propensities for resolving conflict, helping each other, and
overriding impulses that could hurt us in the long run. Our evolved moral sense
enables us to get along with each other (more or less).
Scientists, lawyers, politicians and others spend their days finding
ways to overcome or defeat the horrors of dog-eat-dog nature:
• Scientists try to come up with vaccines and medicines to
counteract the effects of natural pathogens.
• Surgeons try to repair congenital heart problems and any
number of other natural conditions.
• Politicians (in theory) pass laws to help us in our struggle to
survive and to protect us from our natural impulses to harm
or exploit each other; police forces try (in theory) to enforce
those laws.
• Teachers pass on information that enables us to acquire
what we need to survive.
Humans’ evolved empathy and moral sense are
adaptations that enable most of us to rise above utterly selfish, brutish
behaviour. By behaving humanely, humans defy nature.
Non-human animals such as lions, eagles, and
bears have no ethical sense, and behave with breathtaking selfishness,
callousness, and savagery towards all but their immediate kin. Normal human behaviour is saintly by comparison. Most people behave “humanely” most of the
time, not just towards family and friends, but also towards perfect strangers
and animals.
If humans had not evolved an ethical sense, Homo sapiens likely
would have died out long ago. Constant warfare, natural
pathogens, predators and other natural phenomena would have
done in the human species by now. (Of course, darker human
impulses of those with access to massive technology-based
power may one day win out and lead to our quick extinction.)
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Humans evolved the ultimate weapon in the evolutionary arms
race: intelligence. We have the ability, through language, to share
and pool survival-related information and pass it on to future
generations through culture. This has allowed humans to get around
most defences of most other organisms (although microorganisms
still kill millions of our species). We can kill predators such as lions
and bears that would easily be able to kill us if we did not have the
intelligence to make and use weapons.
For Darwinian evolution by natural selection or sexual selection
to proceed, several conditions must obtain:
1. Selection: Selective pressure must exist. Species evolve to
fit imposed environmental conditions (survival of the fittest).
2. Variation: Genetic variability must exist. Chance mutations
and errors in gene replication cause genetic variability to be
present among the individuals of a population.
3. Heredity: Replication must occur in order to pass on genetic
mutations to future generations.
The replicating entities are genes. Living things do not replicate.
Only their genes replicate through their offspring.
Inherited traits that enhance the ability of future replicating
entities to replicate are the adaptations. For an adaptation such as
music to continue in future generations, it must confer either
naturally-selected survival benefits or sexually-selected reproductive
benefits (or both). Music probably confers survival benefits in infancy
and reproductive benefits later in life.
1.5.2
DAWKINS’
“SELFISH
GENE”:
GENE’S
EYE
VIEW
OF EVOLUTION
... the fundamental unit of selection, and therefore of self-interest, is not
the species, nor the group, nor even, strictly, the individual. It is the gene,
the unit of heredity.
—RICHARD DAWKINS
E. O. Wilson pointed
out decades ago that evolution is really all about gene preservation and
replication. This “gene’s-eye view” of natural and sexual selection is usually
referred to as “selfish gene” theory, after the book, The Selfish Gene, by the British zoologist,
Richard Dawkins. Selfish gene theory has become the dominant
framework used in explaining adaptations and adaptive behaviour in
evolutionary biology and psychology.
“Selfish
gene” metaphorically explains how genes become successful by behaving in a
pitiless, “selfish” way. Of course genes don’t “think” and “act”—they’re
blind, deaf, mute chemicals that build living organisms. If the organism dies
before the gene it hosts successfully replicates, the gene fails. If the
organism lives long enough to replicate, then the gene it hosts succeeds in
continuing on to another generation. Genes, then—not bodies—are the actual units
of biological selection and replication. The individuals that genes construct
(plants, animals, bacteria, etc.) serve only as vehicles to pass on genes.
Genes
create adaptations—units of biological function that have survival or
reproductive benefits for the individual. Adaptations such as music and language
actually benefit the gene, because the gene replicates, not the body. In that
sense, genes behave “selfishly.” But that does not necessarily mean the organisms
the genes create behave utterly selfishly. It’s often to the advantage of genes
to select for unselfishness as a behavioural trait in the organisms they build.
For example:
• Parents behave unselfishly
towards their own children, who carry their parents’ genes.
• Children
benefit from their parents’ caring, nurturing, unselfish behaviour by surviving
to reproductive age, still carrying their parents' genes.
• Those
children pass on their parents’ genes to yet another generation.
Organisms
eventually die, but the genes they once carried keep replicating. Most humans
and all non-human animals have no idea that genes made them, and that if they
have offspring, they will have successfully served as vehicles for gene
replication. It’s important to keep in mind that genes are not living things.
They are just strands of DNA—a decidedly non-living molecule. Humans are neither
cold, calculating “gene machines” nor “blank slates,” programmed by the social
environment.
In the discussions coming up about why music evolved in
humans, keep in mind how adaptations evolve in light of selfish gene
theory. Genes build adaptations of the body and brain that enable
humans to successfully survive, reproduce, and pass on copies of
... genes.
1.5.3
HOOTIN’
AND HOWLIN’
REVISITED:
SOUND
AS A SIGNALLING
DEVICE
IN ANIMALS
Why did animals evolve the use of sound in the first place?
As a signalling device for warning and for mate-attraction.
To be a successful adaptation, the signal must not only benefit
the individual(s) being signalled; it must also benefit the signaller
(selfish genes at work).
• A signal used as a threat warns a competitor to back off, or
face a potentially injurious (or lethal) fight.
• A
signal use as a warning advises close kin (carrying the signaller’s genes) of a
nearby predator.
• A contact signal keeps a group together; safety in numbers.
• A courtship signal in humans takes the form of a display of
musical ability, signalling mental fitness.
Animals use other signalling devices as well: smell and sight. But
sound has several advantages:
• Sound works when the signaller and receiver are far apart,
even though they can see each other.
• Sound
works when the signaller and receiver cannot see each other because it’s too
dark or because objects such as bushes or rocks stand between them.
• Sound
can carry messages that vary with the signaller’s call.
Our Homo sapiens ancestors, with incredibly effective sound-based signalling and communication adaptations we call music and
language, out-survived all other hominid species. Evolutionary
biologists, psychologists, anthropologists, and musicologists have
come up with several well-supported hypotheses about selective
pressures that gave rise to the human adaptation for music. These
explanations do not mutually exclude each other. Following are
some of the main ones.
1.5.4
MUSIC
AS AN ADAPTATION
FOR MOTHER-INFANT
COMMUNICATION:
WE’RE
ALL
“PREEMIES”
AT BIRTH
Selective pressure
for group living favoured a large brain size (encephalation) and also two-legged
walking and running (bipedalism). In hominid females, bipedalism narrowed the
birth canal substantially. This placed an upper limit on the size of a newborn’s
head that could squeeze through the birth canal.
It
also place an upper limit on gestation length. In the human species, babies are
actually born significantly prematurely. We’re all “preemies.” As a result, at
birth, human babies are completely helpless, and remain so for a significant
length of time.
Meanwhile, if a pre-linguistic human infant has any hope of
surviving, it needs some way to continually communicate its many
and constant needs with its mother. And the mother needs a way of
knowing for certain that she is meeting those needs successfully.
Since newborns do not have language, meaningful mother-infant
communication must take other forms.
1.5.5
MUSIC
AS AN ADAPTATION
FOR MOTHER-INFANT
COMMUNICATION:
“MOTHERESE”
According to the mother-infant communication hypothesis of the
distinguished scholar Ellen Dissanayake, selective pressure gave
rise to music as a vocal and rhythmic communication and
coordination system between mothers and pre-linguistic infants. This
enabled better maternal care over a longer period of time, and better
survival rates of infants into childhood and adulthood.
Pre-linguistic infants have and use musical abilities at birth. So
do handicapped children and adults born without any capacity to
learn language.
Worldwide,
mothers vocalize with their infants in a particular, distinctive style called “motherese.”
Mothers do not learn motherese culturally—they’re born with it, evidence that
selective pressure evolved the brain circuitry to do this.
Motherese has a number of clearly musical characteristics:
• Melodic (variably pitched)
• Repetitive
• Grouped in phrases of 3 to 4 seconds, like the phrase
groupings of poetry and music found in every culture.
As well, mothers communicate with infants via rhythmic, rocking
motions, possibly a precursor to dancing. Both vocalization and
rocking, rhythmic motions are hallmarks of music as a temporal art.
Myth of the “Mozart Effect”
“Listening to Mozart makes you smarter,” was the
claim. The “Mozart effect” became a fad.
The governors of a couple of American states requested the
issuing of Mozart CDs to all new mothers. One entrepreneur
cashed in on the craze with a book and series of recordings.
It started in the early 90's when a team of
researchers published findings that indicated spatial and temporal abilities
improved in subjects after passive exposure to music composed by Mozart. Other
researchers could not replicate the findings. Further research found that the
so-called Mozart effect had nothing to do with Mozart’s music, but could be
replicated with any stimulus of the subject’s preference (e.g., a narrated
story, or some other music).
However, if a child begins creating and learning music actively at
a young age, the brain responds by allocating more neural matter
to musical processing than the child would have if he or she did
not actively study and learn music. As well, research indicates
that children from inner-city backgrounds who get ongoing, long-term musical instruction through projects such as MusicLink
(http://www.musiclinkfoundation.org/) do much better than their
disadvantaged circumstances would otherwise predict.
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Initially, an infant, being a preemie, has little capacity to respond
to motherese. After a couple of months, the infant begins to vocalize
positively, smile, and respond positively to rhythmic interaction. A
mother-infant feedback loop of emotional communication develops.
Infant-to-mother emotional communication via musical code
sends messages of hunger, frustration, distress. And also positive
communication: contentment, happiness. Mothers know how to
decode the messages, and also how to communicate back to the
infant in the same non-verbal, emotional, musical way. This two-way
non-verbal communication strongly reinforces mother-infant
bonding.
Neither
infant nor mother need to learn how to communicate emoti
