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Chapter 7
Minds and Selves
The discussion of mind development
in the previous chapter placed emphasis on the developing brain selecting what
works best, given its particular genetic background and the physical and social
environment it encounters. In recent years, however, more and more experiments
have revealed that the human brain is a curious and active creature, exploring
its world and actively constructing responses. This chapter starts with a description
of early stages in the formation of human selves---stages that correspond to
maturational processes in our developing brain hardware. What emerges in the
first few years, distinctive to us human animals, is the child as a storyteller,
a narrative autobiographical self. The second part of the chapter examines,
from several points of view, the question of what a human self is: how it might
be distinct from the selves of other animals and how its nature has been revealed
in clinical studies of brain-damaged adults. The third section describes the
self as a modular entity, containing different classes of intelligences and
even different personalities. In the final section, we shall try to pull together
some ideas on nature and nurture in the formation of selves. Evidence has linked
genetic factors to complex behavioral traits, and our fundamental working model
of what a self is can be influenced by cultural surroundings.
Stages in the Development of Human
Selves
During the first few years of life,
human infants are in the process of growing brains that look very similar to
other primate brains. There is no evidence that humans have neuron types or
circuits that are fundamentally different from those of the great apes, for
example, although more of the cortex is occupied by association areas. Frontal
lobes and regions of the cerebellum are also relatively larger. Brain imaging
studies show that subcortical structures are most active at birth; then occipital,
temporal, and parietal activity corresponding to sensory-motor development
increases most rapidly between 3 and 6 months; and a rapid increase in frontal
lobe activity occurs between 8 and 10 months. At this time, long-range connections
between major brain regions are being laid down. These may be the anatomical
basis of an array of correlated changes that are taking place in language,
communication, and cognition. During this period, faculties such as tool use,
intentional communication, imitation, and retrieval of hidden objects retrieval
are coming into play. Words are comprehended, and nonnative speech sounds are
suppressed. Between 9 and 24 months, the density of synaptic connections between
brain cells reaches 150 percent of adult levels, as a rapid acceleration occurs
in the acquisition of vocabulary, grammar, symbolic play, and categorization
abilities. By 48 months, overall brain metabolism has peaked, most grammatical
structures have been acquired, and a period of stabilization begins. Brain
metabolism and the density of synaptic connections then begin to decline, and
they continue to decrease until, after puberty, they reach adult levels. The
elimination of connections may be driven by a competition that favors the survival
of those that are working best. Superior frontal cortex, involved in higher
functions, continues to increase in volume from 8 to 25 years of age.
By the age of 12 to 18 months,
humans have become little natural scientists, expressing an instinct to learn.
Dolls that don't follow physical rules cause startle reactions, and basic aspects
of objects are understood: how objects set in motion continue to move, how
one object can support another placed on top of it, and how an object still
exists even if another object blocks its view. A human baby looking in a mirror
takes his or her image to be another child until the age of about 18 months,
when it recognizes the image as its own. At this age humans also recognize
any conflict between the tone an adult often uses when speaking to a child
and the content of the spoken message (for example, saying "don't touch
that" in a cooing, calm, and smooth voice). At around 2 years of age,
the entire grammar of a language blossoms over a period of about 6 months.
A simple experiment demonstrates that between the ages of 3 and 4, others are
assigned a separate mind. At age 3 a child who observes matches being put in
a crayon box says that a toy rabbit that was absent when this was happening
also knows the box contains matches. The child is not able to conceive of the
mind it attributes to the rabbit as being different from its own mind. At age
4 the child will say the rabbit thinks the box has crayons because the rabbit
didn't see the matches being substituted for them. This is clear evidence for
the development of an ability to ascribe minds holding beliefs (in this case,
a false belief) to others.
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DESIGN NOTE: IMPORTANT POINT
It appears that we all begin as "little
scientists" who pass through a sequence of stages in discovering facts
about the physical world and the minds of other humans.
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Contemporary studies, all influenced
by Piaget's work on child development, have given rise to several different
descriptions of stages in mental development. One model suggests that the ability
to ascribe mental states to others develops in four sequential cognitive stages:
an intentionality detector, an eye-direction detector, a mechanism for sharing
attention to an object with another person, and a theory-of-mind mechanism.
Using this scheme, autism might be described as a sort of "mind-blindness" caused
by breakdown of the transition between the second and third steps, such that
autistic people are largely unaware that other people have minds. Another
description presents the child as physicist, then mathematician, then psychologist,
annotator, and linguist, proceeding from unconscious knowledge through conscious
knowledge to verbally expressed knowledge. Each of these areas is suggested
to be an internal module present in all humans. A
further categorization is of the sequential development of a so-called point
mode (2--3 months) for sensing and controlling present environments, followed
by a line mode (8--10 months) that adds future and past to the present. Then
follows a construct mode (1--2 years) that detaches from specific place or
time to generalize away from the "I." A transcendent mode (8--10
years) then makes it possible for the child to analyze patterns and relationships
outside of a specific place and time.
Effects of Rich Versus Impoverished
Environments
Development of many areas of the
brain both in humans and in other developing animals is a function of the presence
(or absence) of rich and varied interaction with the environment. Rats raised
with multiple (rather than single) families or with toys (rather than without)
have 10--20 percent thicker cerebral cortexes. Their brain nerve cells are
larger and have many more connections. The effects of environment can persist
in the adult; adult mice living in cages that contain toys, nests, tunnels,
and play wheels have more hippocampal neurons than mice kept in a standard
laboratory box that contains only food and water. Many
young animals devote 20 percent or more of their energy to play activities
such as leaping, jousting, pouncing, chasing, and nipping. In these activities
they expose themselves to predators, at some risk to their health and safety.
Synapse formation, particularly in the cerebellum, is at its height during
this play period, which also serves as rehearsal of many of the moves needed
as adults: mock flight, stalking, and biting. In highly social species like
monkeys, the young spend half their waking time at play, with males engaging
in rough-and-tumble play while females emphasize chase games. How to win and
lose and rules of submission and dominance are worked out. In humans and other
animals there appears to be a critical period extending into early adult life
for the formation of self-image and social skills. Nerve connections in the
frontal lobes continue to multiply during this time. An important function
of culture is to program young brains in social rules and procedures during
this critical receptive period; those internalized social routines then remain
relatively constant throughout adult life. There appears to be increasing acceptance
of the idea that peer relationships are more important than parental or adult
models in patterning social behaviors during this critical period. Adolescents
are much more interested in being like other adolescents than in being like
adults.
Impoverished environments appear
to have the opposite effect of rich and varied surroundings: They suppress
brain development. In humans exposed to early stressful or abusive conditions,
retarded development of the hippocampus and impairment of short-term verbal
memory have been observed. Brutality
and cruelty to children can cause changes to their brain chemistry, altering
the levels of neurotransmitters such as serotonin. Romanian orphans who experienced
profound overcrowding and deprivation of adult touch and holding exhibited
changes strikingly similar to those observed in baby monkeys removed from their
mothers after birth and reared without parental care. Growth is stunted and
social behavior profoundly disturbed. The
message here is that there are critical periods in human development during
which not only primary sensory and motor pathways, but also pathways regulating
complex social behaviors, are laid down. After these windows of opportunity
for plasticity have passed, the brain becomes unreceptive to further major
changes. Language, if not mastered by the time of adolescence, is never learned.
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DESIGN NOTE: IMPORTANT POINT
In humans exposed to early stressful
or abusive conditions, retarded development of the hippocampus and impairment
of short-term verbal memory have been observed. Brutality and cruelty to children
can alter their brain chemistry.
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The Role of Language
The learning of verbal language
plays a central role in the development of human selves. The amazing plasticity
of the brain allows this process to take place also in congenitally deaf children
of normal intelligence, who have no difficulty learning a highly sophisticated
sign language. Recent studies suggest that the amount of language to which
an infant 6 months to 3 years old is exposed each day---from an engaged and
attentive adult human, not TV or radio---is the most reliable predictor of
later intelligence and social competence. One
suggestion is that language
ability forms during human development out of mimetic social sharing of signs
and communicative behavior (see Chapter 5). Event
representations are taken to be the fundamental units of memory; very young
children demonstrate quite good memories for recurrent features of common events.
The basic idea is that the social communicative capabilities of the infant
constitute the preparation for language. An autobiographical and narrative
self then arises to make sense of reality.
The philosopher Daniel Dennett
emphasizes that the fundamental tactic of human self-protection, self-control,
and self-definition is telling stories---concocting and controlling the story
we tell others and ourselves about who we are. This storytelling derives from
the mythic personality discussed in Chapter 5. Just as spiders don't have to
think consciously and deliberately about how to spin their webs, and just as
beavers, unlike human engineers, don't deliberately plan the structures they
build, we do not consciously and deliberately figure out what narratives to
tell and how to tell them (unless were are professional storytellers or con
artists). Our tales are spun, but for the most part we don't spin them. They
spin us. Our human consciousness and our narrative selfhood are their product,
not their source. The making of stories and myths leads humans to do something
that no other animal does: to deceive themselves in a sustained way. All groups
of humans create imaginary worlds and myths about life after death. This requires
going against empirical reality and physical evidence. Different cultures do
this in different ways, but they all do it.
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DESIGN NOTE: IMPORTANT POINT
Human selves and groups are suspended
in webs of significance that they themselves have spun. We make sense of the
world by telling stories about it, using a narrative mode to construe reality.
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The Cerebral Hemispheres as Selves
Fascinating insight into the composition
of selves comes from clinical studies of brain-damaged patients. Some such
studies have shown that our two cerebral hemispheres can act as separate selves and
that one's normal sense of oneself as a coherent being is achieved by neurally
connecting a family of distinct operations carried out semi-independently in
each hemisphere. Recall that each of these hemispheres senses and influences
the opposite, or contralateral, side of the body. They talk to each other via
a thick bundle of nerve fibers called the corpus callosum. One treatment for
epilepsy has been to cut this bundle. The surprising finding is that each hemisphere
carries an independent awareness of the self.
Each hemisphere of a split-brain
patient is aware of tactile stimuli applied to the opposite side of the body
but is unaware of those applied to the same side. Conflicting or opposing commands
can be given to each hemisphere, because the left ear reports to the right
hemisphere and the right ear to the left hemisphere. The cognitive neuroscientist
Michael Gazzaniga and others have shown that distinctive features of the two
hemispheres can be revealed by experiments on visual performance. They make
use of the fact that our left hemisphere sees the right part of our visual
world while the right hemisphere sees the left. Figure 7-1 shows how this happens.
The left sides of our two retinas, which see the right visual field, send their
information to the left hemisphere. The right sides of the retinas see the
left visual field and send information to the right hemisphere. If we fix our
gaze on the dotted line running through the word HEART in Figure 7-1 and arrange
it so that the HE is projected on our right retina and the ART on the left
retina, we report the word HEART because the two cortexes communicate, via
the corpus callosum, to figure out the whole image.
Figure 7-1
This schematic drawing illustrates
how it is that information from the right and left sides of our visual world
is sent, respectively, to the visual areas of the left and right cerebral hemispheres.
The left side of the left retina and the left side of the right retina, shown
as the solid lines, send information about the right visual world to the left
occipical cortex, and the right sides of the retinas, shown as the dotted lines,
send information to the right cortex. If the bundle of fibers connecting the
two hemispheres, the corpus callosum, is cut, then one side does not know what
the other is seeing.
If asked to name what is seen,
however, a split-brain patient says ART because the left hemisphere is the
seat of language and can issue a report. The HE part of the word cannot be
expressed because it is shown to the right hemisphere, which cannot speak.
The mute right hemisphere does know what is going on, however, because the
subject will select a picture of a man from a series of photographs if asked
to match what is seen. If the letters DOG are flashed to the right hemisphere,
the subject can select a model of a dog with the left hand. These simple language
operations can be carried out by the right hemisphere, but more complicated
ones cannot. Although the right hemisphere cannot talk, it can perceive, learn,
remember, and issue commands for motor tasks.
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DESIGN NOTE: SELF-EXPERIMENT
Imagine for a moment what it must
be like to be the right-hemisphere self in a split-brain patient. There you
are, trapped in the right half of the brain in a body whose left side you know
intimately and still control and whose right side is now as remote as the body
of a passing stranger. You want to tell the world what it is like, but you
can't. You are cut off from verbal communication, which is generated from the
left hemisphere of the brain, to which you have lost your direct connection.
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The splitting of the visual world
between the two hemispheres has been used as the basis for a series of experiments
with what are called chimeric photographs. If the right visual field contains,
say, a woodland scene and the left shows an erotic nude, the subject verbally
reports seeing the woodland but becomes agitated without knowing why. Sometimes
an explanation for this arousal is invented, or confabulated. In such a case,
the left hemisphere is using its language competence to report the best story
it can make up, given the circumstances. Conflicts between the two hemispheres
can become even more dramatic. One patient who was prone to aggressive emotional
outbursts, which are usually associated with the right hemisphere, used this
hemisphere to command his left hand to pick up a hammer to attack a researcher.
A struggle then ensued between the two functional selves present, as the right
hand, controlled by the left hemisphere, moved to restrain the left! We could
not ask for a clearer demonstration of two selves in one brain.
Self-Boundaries
The entity that we call our self
can expand or contract. In expansion of the self-boundary, we take something "out
there" as though it were part of ourselves: a car, job, house, or reputation.
Any threat perceived to that entity then is felt as a threat to our very survival.
Simple to say, but very basic. Perhaps you recall how you felt when the first
scratch appeared on the finish of a new car you were extremely proud off. You
may also recall instances of self-boundary contraction. "I didn't do that!
That wasn't the real me talking. Yes, the words came out of my mouth, but I
refuse to recognize them as my own." These boundaries are influenced by
whether we are feeling good or bad about ourselves. When asked to identify
their own voices from a series of recordings, subjects with high self-esteem
claim to own other people's voices, whereas depressed subjects claim too few
voices as their own. And all the while, in both cases, the galvanic skin response
shows that the information is being tallied correctly by the autonomic nervous
system.
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DESIGN NOTE: SELF-EXPERIMENT
You might try the following experiment
with a group of friends: Put a paper sack on the desk and ask the group to
imagine that something very important and valuable to them is in the sack,
perhaps a gift from a loved one. Carefully close the top of the sack as though
to seal in its value, and then---without warning---suddenly smash your fist
down on the sack to crush it. You might hear an excited gasp or two. After
apologizing for causing this discomfort in the service of the demonstration,
ask your friends what they felt. Did they experience contraction of the chest
and front flexors, and a slight feeling of pain and loss?
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Observations on patients with brain
lesions suggest that the experience of self and self-boundaries requires a
continuous sensing of body states. Most patients commonly experience the loss
of an ability (such as the ability to recognize faces, to see colors, or to
read) as something happening to them and describe it in the sorts of terms
one would use in describing a back problem. They see the problem afflicting
their selves. However, in extreme cases of anosognosia (denial of a part of
the body, frequently associated with damage to the right parietal lobe), the
problem is not referred to the self; it is denied. When a right-hemisphere
lesion blocks sensing and movement of the left side, the existence of the left
arm can be denied, or a story can be fabricated to explain its presence. One
suggestion is that the emotions associated with monitoring discrepancies and
anomalies are located in the right hemisphere. This perhaps underlies the fact
that some anosognosic patients with right-hemisphere lesions who deny the existence
of parts of their bodies are much more likely to engage in elaborate and fanciful
rationalizations than either normal individuals or those with left-hemisphere
damage. The idea is that the
job of the left hemisphere is to make up plausible stories. If something goes
wrong, it denies or confabulates to try to make aberrant information fit in.
The right hemisphere detects anomalies and, if they become serious enough,
forces the left to start from scratch with a new story line. Damage to the
right hemisphere can delete this editorial function.
Experiments on split-brain subjects
of the sort we have mentioned also reveal the role of the self as a presentation
manager, a story-line generator. In split-brain patients, an instruction to "walk" can
be flashed to the right hemisphere (some patients, especially left-handed people,
retain the ability to understand simple linguistic commands with their right
hemisphere). The linguistic, speech-generating left hemisphere has no knowledge
of this instruction. When the patient gets up and begins to walk about the
room and is asked why, a rational (though bogus) explanation is generated,
such as "Uh, I'm going to get a Coke."
Similar behavior can be elicited
from normal subjects in hypnosis experiments. A subject under hypnosis can
be given a posthypnotic suggestion for a trivial activity, such as an instruction
to crawl about on the floor. After coming out of hypnosis, the subject might
be engaged in a normal activity, such as drinking coffee with the experimenter,
and then suddenly say something like "What a fascinating floor pattern" or "I
want to check out this rug" and then proceed to crawl around on the floor.
It would appear that programs in the brain, on the basis of the information
available to consciousness, present a plausible story to account for the subject's
actions. "I'm acting out a hypnotic suggestion" is not part of the
available information.
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DESIGN NOTE: SELF-EXPERIMENT
Our self and body images can be
altered by sensory incongruities or conflicts. Here is an experiment you could
try with some friends: Sit at a table with your left arm resting on the table
to your left but hidden from your view by a screen. Have another person sitting
to your right place his or her left arm on the table directly in front of you
(alternatively, a rubber model of a left hand and arm can be placedin front
of you). Now, a third accomplice uses two small paintbrushes to stroke both
your hidden hand and the hand of the arm you can see in front of you, synchronizing
the timing of the brushing as closely as possible. If you are like virtually
all of the people that try this test, you will soon start to feel as though
the touch you can feel is in the position of the hand you can see and that
this visible hand is your own! Your brain has altered its representation of
your body in space, and you are feeling a phantom limb, just as amputation
patients sometimes do. You are literally having an "out of body" experience.
If a drop of cold water is applied to your hidden hand, the cold can sometimes
be felt in the location of the new hand.
Variations on this experiment show
that we can similarly displace our experience of our nose---or even of our
entire head. These demonstrations show how our body image, despite its apparent
durability and constancy, is a transitory construct that can be altered by
the stimuli we actually encounter.
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Selves Are Modular Constructions
From a variety of sources, we obtain
clues that human selves consist of several semi-independent modules. Genetic
and developmental studies reveal a set of core intelligences that together
assemble an "I." The psychologist Howard Gardner has suggested that
several intelligences should be distinguished as basic to our different areas
of competence: logical-mathematical, linguistic, spatial, musical, bodily kinesthetic,
and personal-interpersonal. Evidence
for the distinctiveness of these intelligences comes from studies of their
development and also from observations on geniuses and on idiot savants (who
are born with some exceptional abilities but are retarded with respect to others).
To take just a few examples, evidence
for logical-mathematical intelligence comes from the demonstration of innate
mathematical ability in human infants, who can perform simple addition and
subtraction at the age of 5 months. It
is also supported by the existence of individuals who are precocious by genetic
endowment. Pascal was forbidden by his father to speak about mathematics. Therefore,
he made simple geometrical drawings on the walls of his playroom, devised his
own mathematical terms and axioms, and rediscovered the propositions of Euclid. The
presence of a genetic component in musical competence is suggested by infant
prodigies such as Mozart, Mendelssohn, and Saint-Saens. Nijinsky, Barishnikov,
and Marcel Marceau offer examples of precocious kinesthetic intelligence. Note,
however, that the argument for a genetic component in the exceptional behavior
of these individuals has to be tempered by that fact that some were exposed
to distinctively different early experiences, preferences, opportunities, habits,
training, or practice.
The multiple-intelligences model
suggests an array of core computational capacities, such as phonological and
grammatical processing for language, and tonal and rhythmic processing for
music, rather than the general intelligence, or so-called g factor, of the
IQ psychologists. In some cases,
these computational capacities might be largely localized to specific regions
of the brain, for some are compromised by damage to specific brain areas. Others
might be spread more widely across different areas. Recent genetic studies,
mentioned below, do provide support for a heritable component of general intelligence,
perhaps due to variations in very basic parameters that influence the whole
brain, such as nerve signal conduction or the ease of making new nerve connections.
The Example of Musical Intelligence
Let's focus on music for a moment.
It is tempting to compare human music to bird song, for which there are definite
brain specializations. The function of bird song is communication, and song
may have preceded speech in humans, as a component of the mimetic intelligence
that existed before the appearance of grammatical language. As we all know,
music is strongly linked to emotion. The first musical instrument was the human
voice, but there is evidence for musical instruments (pipes and flutes) dating
back to 50,000 years ago, and there is presumptive evidence of the role of
music in organizing work groups, hunting parties, and religious rites. The
development of musical skills, like that of the other proposed modules of intelligence,
follows a stereotyped course, so that, for instance, 4-month-old babies are
sensitive to consonance versus dissonance, 6-month-old
babies detect musical patterns, and 2-year-old children spontaneously pick
up and sing songs to themselves during play.
Clinical evidence points to a modular
musical faculty. There are numerous cases of brain-damaged children, some autistic,
who have exceptional musical ability. Injuries to the right frontal and temporal
lobes can cause difficulties in discriminating tones and reproducing them (amusia).
In some subjects who have damage to areas in both the left and the right temporal
lobes (where auditory circuits dealing with pitch reside), speech and auditory
faculties seem normal, but the subjects cannot recognize specific music or
songs. However, they still
can follow rhythm and the emotional content of the music. The Russian composer
Shebalin developed a severe Wernicke's aphasia but remained able to compose
competently. In the last 4 years of his life, Maurice Ravel lost the ability
to compose or play music, but he could listen to and appreciate musical pieces.
The mechanisms for apprehending
and storing pitch, like a set of tones, are separate from those used for the
sounds of language. Remembering a set of tones is not compromised by random
verbal interference, but it is disrupted by random competing tones. Musical
composers describe themselves as constantly having tones in their head, generating
musical phrases without thinking about it. These lines of evidence for functional
and anatomical modules of musical competence cannot be taken to mean that it
is an isolated faculty, however, for musical activity interacts with other
intelligences. Listening to Mozart results in better performance on spatial
tasks, and 3-year-old children given weekly piano lessons register 80 percent
higher scores in spatial and temporal reasoning than average.
How Many Selves to a Customer?
While we are considering information
on known or proposed modules of selves, let's look at the variety of selves
or intelligences that we might contain from another angle: the idea that each
of us is not one self but many different semicomplete selves. You probably
have been jarred occasionally, when in a critical mood, upon realizing that
the style of your speaking and criticism is very similar to the way in which
you were corrected by your parents. Or, after being subjected to sudden criticism,
you may find yourself cringing just the way you did as a child. We all seem
to have a continuous experience of an "I," but the "I" in
place (the resident self) can change from moment to moment. It is as though
we are made up of a club, or a board of directors, one of whom is in command
at any given time. Members
of this board can include our present and past personalities, as well as the
personalities of others who are (or were) important in our life. The hint that
our continuous experience of an "I" is a fiction is its troublesome
instability: the fact that we can act as though we were different people at
different times and often seem relatively powerless to control who we are and
when. This is because the "I" consists of a succession of emergent
personalities, and which one presides at any particular time depends on the
circumstances.
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DESIGN NOTE: SELF-EXPERIMENT
Can you recall a moment when, with
a start, you realized that you were feeling and speaking not from a present-centered
adult perspective, but rather exactly as you did when you were a small child.
And at other times, have you suddenly thought while you are speaking, "I
sound just like my parents"?
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Descriptions of how we develop
these processes, from Freud's analysis to the present, have a number of common
themes. Although different schools use different jargon to describe the process
and to generate therapies that typically come into vogue for 5--10 years, they
all share the theme of modeling the expression of several humans, sometimes
called ego states, within us. As an example, you may have heard of "transactional
analysis," a popularized incarnation of Freudian therapy that peaked in
the 1970s. It describes a parent ego state that is imprinted on our brains
when we are young and that has two main components: a nurturing, caretaking
parent and a critical, judgmental parent. This parent ego state contains the
rules for outward behavior toward others. Rituals seen in the parents are internalized,
as are the parents' inward instructions to self. The child ego state consists
of permanent records in our brain of the way we experienced our own impulses
as a child and how we felt about the world. It contains at least three components.
A "natural child" is affectionate, impulsive, sensuous, uncensored,
curious but also fearful, self-indulgent, self-centered, rebellious, and aggressive.
A "little professor" is intuitive, creative, manipulative, and playful.
Finally, an "adaptive child" accommodates to the demands of parents
and the social world, being courteous and compliant, avoiding confrontation,
procrastinating, and withdrawing. Finally, an adult ego state is meant to be
the "reality-testing machine" that is centered in the present rather
than being a read-out of the more primitive parent state or child state. This
adult ego state is the executive that chooses whether a novel output or one
from the parent or child state is appropriate. It is the component that psychotherapies
attempt to strengthen.
This sort of description of the
self as made up of many selves does not explain how any particular self works.
Indeed, the field of psychology has entertained a series of theories that have
rarely outlived more than a few generations of their proponents. Most psychological
explanatory theories, such as psychoanalysis and the postulating of the Freudian
unconscious, have not been cast in a form that can be either proved or refuted. Some
psychologists have been criticized for inappropriately trying to imitate the
quantitative analyses that are often possible in biology and physics. One example,
mentioned below, is the attempt to describe a very complex and modular phenomenon,
intelligence, by a single number, the IQ or intelligence quotient.
Yet another perspective on the
issue of how many selves each of us has comes from considering apparent fractional
as well as multiple personalities. There is the case of the twin sisters in
York, England, who live together in a hostel and seem to act together as one
individual, collaborating in single speech acts in sequence or in unison. It
seems natural to regard "them" as more of a "her." Oliver
Sacks describes two brothers, identical twins with IQs of 60, who, only when
together, and communicating by a variety of tics, twitches, head bobbing, and
rolling eyes, could perform prodigious feats of mental calculation.
More striking are the many purported
cases of multiple personality disorder. The model has been that traumatic childhood
experiences such as physical or sexual abuse cause a child to decide that the
horror is happening to someone else and thus generate several independent personalities.
In the case of Billy Milligan, an Ohio jury determined that he could not be
punished for the crime (rape) committed by one of his parts. There are anecdotal
reports of changes in patterns of allergies, phobias, and movement habits between
different personalities. The newer name for this condition, dissociative identity
disorder, reflects uncertainty over whether a patient identifying himself in
multiple ways is really displaying identities that constitute personalities. Indeed,
handing down the diagnosis of multiple personality disorder, which started
in the 1950s, has proved to be a fad that has subsided. The condition appears
mainly to have been the product of suggestible patients, misinformed diagnoses,
and incompetent therapy involving suggestive techniques such as hypnosis. Several
well-publicized epidemics of altered behaviors, in addition to dissociative
identity disorder, have the curious feature of being reported largely for Northern
American and European populations. While some of these (such as seasonal affective
disorder, attention-deficit/hyperactivity disorder, chronic fatigue syndrome)
appear to have a biological basis and probably occur more widely, others are
more problematic (such as the numerous cases recently reported of recovered
memories of sexual abuse, satanic ritual abuse, and alien abductions).
Selves, Genes, and Environments
This and the previous chapter have
cited numerous examples of how the human mind can end up in different possible
configurations. To what extent are these configurations captive to the genetic
instruction we are born with, and to what extent are they patterned by our
physical and social environments? Numerous studies have argued that several
components of human personality tend to remain constant throughout an individual's
life and have a heritable component. Such stable traits include novelty seeking,
harm avoidance, reward dependence, persistence, extraversion/introversion,
emotional stability, and sexual orientation. Most
of the work to date has correlated overall genetic constitution with behavior,
but more recent studies have noted correlations between mutant forms of single
genes and behaviors such as nurturing, novelty seeking, and drug addiction.
Studies on identical twins raised apart sometimes reveal similarities in detailed
mannerisms that may reflect their shared genetic and intrauterine hormonal
environment. There is clear evidence from studies that compare identical (monozygotic)
with nonidentical (fraternal, dizygotic) twins that genetic factors account
for at least 50 percent of the difference in general cognitive ability (including
social cognition) between individuals. It may be that variations in a higher
faculty such as social cognition are actually the consequence of more general
underlying differences in attentional or motor mechanisms of the brain. Although
there is some evidence that general intelligence correlates with higher brain
metabolism, faster conduction velocities, and bigger brains, there are no generally
accepted links between differences in most cognitive performance and variance
in underlying brain mechanisms.
Framing the Issue of Nature and
Nurture
We need to be aware of a potential
fallacy lurking in the debate over whether certain character traits, and, in
particular, general intelligence as measured by the IQ test, have a genetic
basis. That possible fallacy is the assumption that a complicated behavior
such as intelligence can be measured by a single number, and that it has been
described precisely enough to be measured. Intelligence probably consists of
several dozen abilities influenced by many different genes, each affecting
more than one character. Until we understand this complexity, we can't even
begin to sort out roles of nature and nurture. IQ tests are a crude estimate
of intelligence in the same way that pulse, blood pressure, and body temperature
provide an overview of general health. A physiologist or physician can proceed
to tests of liver function, heart function, and so on, but the ability of a
psychologist to dissect the components of intelligence is much more crude.
In many studies, the implicit assumption
is that some fraction of our behavior is caused by heredity and some fraction
by environment and that the problem is simply to assign the proper percentage
to each. Unfortunately, this assumption frames the issue in a misleading and
oversimplified way. A more appropriate description of what is going on is that
our genes generate options that are tested as an environment provides input
that results in behavior. The usefulness of the behavior in enhancing survival
and reproduction determines what supporting neuronal pathways become permanent.
The author Robert Wright puts this
in more simple language by using an analogy: Heredity provides us with a set
of genes for different traits that you could imagine as being like control
knobs on a stereo amplifier. At
different times during development, different sets of knobs appear and then
disappear. The important thing is that which knobs are selected for use and
how these knobs are tuned depend on constant interactions with the environment---what
settings are most successful in guiding our behavior, seeing food, getting
it to the mouth, communicating with other humans, avoiding predators, and so
on. There is genetic variation among humans, which leads to slightly different
sets of knobs that are tuned more or less broadly.
We must also consider that there
are random events in the development of cells and nervous systems that are
neither genetic nor environmental influences in the usual sense. One example,
given in Chapter 6, is the relative placement of male and female embryos in
utero that can influence female testosterone levels and brain development.
Knowing the genetic basis of a character does not enable us to predict how
changeable that character might be by random, individual, or social circumstances.
This means that mere proof of the heritability of a trait yields very little
information about how malleable it might be.
***************
DESIGN NOTE: IMPORTANT POINT
It is not practical or useful to
try to separate the contributions of environment and genes to our behavior,
because they feed back on each other in an intricate dance that begins in utero
and continues through puberty.
***************
Finding a correlation between a
behavior and a gene is emphatically not the same thing as finding a gene for
the behavior. The philosopher Elliott Sober gives the example of people who
knit and people who do not. With
few exceptions, knitters have two X chromosomes (are females); people with
one X and one Y chromosome (males) almost never knit, at least in contemporary
American culture. This does not mean that we have discovered genes for knitting.
Finding a gene or collection of genes that incline an individual to a given
behavior means that the behavior in this sense is "natural," but
it says nothing about its relevance, usefulness, or acceptability in prevailing
circumstances.
Physical Environments and Selves
The influence of physical environment,
social environment, and language on the formation of human selves is perhaps
easier to appreciate than the influence of genetics, and it is especially striking
when one notes the different cognitive habits and construals of self that are
found across the world. An illustration of the effects of different physical
environments comes from noting the relativity of more complex sensing and acting.
Those who grow up in "right-angle" cultures with rectangular rooms
and shapes are more susceptible to the illusions shown in Figure 7-2 than are
those in Stone Age cultures who live in circular dwellings in the rain forest.
People raised in dense forest, where the relevant visual world is mainly within
50--100 feet, can become alarmed and confused upon seeing savanna for the first
time. Distances of miles cannot be processed, and a herd of buffalo in the
distance is likely to be interpreted as a colony of ants.
Figure 7-2
(a) The Müller-Lyer illusion.
The vertical lines are the same length. Most people, however, report that the
left vertical line is longer than the right, because the left figure is taken
to indicate a corner receding from the viewer and the right figure to indicate
a corner projecting toward the viewer. (b) The Ponzo illusion. Here the horizontal
lines are the same length, but because the lines are between converging straight
lines (like a railroad track), the top line is usually reported as being longer.
This is a reasonable interpretation of cues supplied to a nervous system that
has been trained to interpret perspective and distance involving lines and
edges. (c) The Devil's tuning fork. Most Westerners cannot reproduce this drawing,
but African tribespeople who don't share Western conventions about interpretation
can reproduce it with little difficulty.
Cultural Influences on Self
Different cultures can define self,
others, and their interdependence in strikingly different ways. In
many Asian cultures, interactions among people predominate in the experience
of cognition, motivation, and emotion. The definition of self emphasizes the
relatedness of individuals to each other. The role of a self is to blend into
harmonious relationship with others. American and European culture downplays
this interdependence to construe the self as an independent entity with unique
inner attributes. The role of a self is to discover and express its distinct
potential. Not surprisingly, notions of what are healthful and what are abnormal
behaviors vary between cultures. Anorexia
nervosa seems as culture-bound to America as amok (acting wild and crazy) is
to Malaysia. The Japanese malady taijin kyofusho---a morbid dread that one
will do something that embarrasses other people---has no counterpart in Western
culture or diagnostic systems. Hopi Indians define five different types of
depression that do not match those enumerated in the American Psychiatric Association's
Diagnostic and Statistical Manual of Mental Disorders.
***************
DESIGN NOTE: IMPORTANT POINT
Our nervous systems form in an
ecological dialog with our physical and social environment. Our brains are
shaped by the particular world they grow up in, just as they in turn shape
that world. Their cognitive
structures are heavily influenced by culture. The regions of the brain engaged
by ideographic Chinese and those engaged by phonetic English are different.
The premotor cortex of a professional football player is different from that
of a biblical scholar.
***************
Many of you reading this book have
a sense of individualism and self-consciousness patterned largely by Western
European civilization since the 17th century. All human minds were in a somewhat
different world before then, and many still are. It is striking that the idea
of the self as "a permanent subject of successive and varying states of
consciousness" doesn't appear in the Oxford English Dictionary until the
17th century. This is not to say, however, that the actual nature of human
selves was different before that time. Older classical essays suggest that
the writers had selves very similar to our own, but the great majority of people
were immersed in a more collective group identity, just as in the contemporary
Asian cultures mentioned above. A number of preindustrial societies have little
notion of a person as a separate entity. Both
the Old and the New Testament of the Bible often portray humans not as active
agents of individual decision or choice but rather as passive pawns of an active
God.
By the same token, many patterns
of modern life that you might assume to be "natural" are actually
of recent origin. The Western idea of "home" as an enclosed nurturing
space for one family derives specifically from Amsterdam in the late 17th century. The
work week, with its rigid separation of work and leisure, is an artifact of
the Industrial Revolution. Homosexual
culture as a distinct social category was an invention of the late 19th century.
Our cultural arrangements have an overriding influence on what we consider
normal, and we frequently (and mistakenly) overextend this concept to include "natural" or "biological."
The Relativity of Thought Systems
A discussion of this sort is not
complete without some reference to current discussions of the relativity not
just of selves, languages, and social customs but of all knowledge. One extreme
position has been to label Western science as just another system of magic
that has only as much legitimacy as any other social construct. Popular forms
of irrationalism have become so pervasive that conferences of concerned scientists
have met to address the issue. Because
we are immersed in our world and our nervous systems are shaped by a complex
interplay between our whole bodies and that world, how can anything we know
be considered absolute?
***************
DESIGN NOTE: IMPORTANT POINT
Our view of reality is framed by
the limitations and peculiarities of our sensory apparatus, the prejudices
of our presuppositions, and the restrictions of our language and culture. We
form our ideas of what is correct or true from a network of unconscious, as
well as conscious, bits of information taken in from the environment.
***************
The relativistic position is that
we frame our understanding in terms of very restrictive and culturally specific
metaphors---that the way we have been brought up to perceive our world is not
the only way. Still, even the most severe social constructionist would probably
grant that there are indeed immutable facts about the natural world, even if
our accounts of them can depend on capacities and vocabularies that are socially
constructed. It isn't terribly useful for different cultures to try to step
outside of some core perceptions such as "rocks are hard," "two
plus two is four," and "gravity defines up and down." On the
other hand, there is no obvious reason why different cultures should not arrive
at different conventions of a more superficial sort, such as those reflected
in gender roles or metaphors like "time is money," "labor is
a resource," "love is a journey," and "problems are puzzles."
The coherence of any system of
thought rests on its stability. Does it work? Is it useful? Science distinguishes
itself from mystical or magical traditions in that it seems to meet this criterion
of stability, or usability, better. Most of us probably believe that cultures
based on some kind of scientific rationalism will be more adaptable---and thus
more stable---than those based on magical world views.
Summary
We have now patched together part
of a picture of the active construction of developing selves. Starting from
the activity-dependent early wiring of our brains, discussed in the last chapter,
we all proceed to develop as "little scientists." A human child's
increasing competence in dealing with its physical and social world passes
through a set of stages so stereotyped that it is hard to escape the conclusion
that these stages rely on genetically specified components. However, the expression
of these components---the competence and connectivity of the brains that actually
grow---can be enhanced by rich physical and social environments or inhibited
by impoverished ones. The contributions of specific brain areas to determining
the nature and boundaries of the self are revealed by brain lesions that can
cause a dissociation of the "selves" sensing and controlling the
two sides of the body, or that can cause denial of a physical part of the self.
The left hemisphere is revealed as a "presentation manager" that
can sometimes go awry and confabulate bogus explanations in order to make sense
of contradictory experiences or sensations.
Genetic and developmental studies
suggest that several semi-independent core intelligences contribute to our
repertoire of abilities, and psychological studies present the model of each
of us as a "committee of selves," only one of which is usually the
spokesperson at a given moment. An appreciation of the complexity of selves
and their molding by physical and cultural influences reveals that much of
the public discussion over genes and behavior is simplistic and misguided.
Debate over learned versus innate mechanisms comes into sharpest focus in studies
on language development, and we will conclude our discussion of this topic
when we cover brain mechanisms of language in Chapter 11. The great variety
of selves that humans can form, and the significant cultural differences in
perception, mental categories, and selves construed as independent versus interdependent
entities, show the importance of social factors in constructing selves. To
proceed further in describing human minds and selves, we must now examine more
of the details of their structure and function. Therefore, in Part III of this
book, we will expand on the metaphor of each of us as a society of mind.
Questions for Thought
1. The philosopher Daniel Dennett
makes the point that our brains spin stories about who we are, just as spiders
spin webs or beavers build dams, without consciously and deliberately thinking
about how to do it. Our narrative selfhood is the product of this process,
not its source. Do you agree or disagree with this? Why?
2. Suppose you meet a person whose
hemispheres you know to have been separated by surgery to cut the corpus callosum.
Say you ask this person to look straight ahead and then, without glancing to
the side, name a common object you hold up at the right edge of his or her
visual range. Could the person do it? Why?
3. This chapter discusses the ideas
of multiple intelligences and multiple selves within an individual human. What
kind of evidence supports these models? Do you think one of these concepts
is more plausible than the other?
4. Cultures vary in the relative
value they place on the independence and the interdependence of individuals.
Try to imagine yourself living and experiencing first one, and then the other,
extreme end of these options. From each perspective, what sorts of explanations
might you offer for your behaviors? What might be the roles, from each perspective,
of personal introspection and awareness of personal motives ?
Suggestions for Further General
Reading
Donaldson, M. 1992. Human Minds.
New York: Penguin Press. One account of stages in the development of the human
mind.
Pinker, S. 1997. How the Mind Works.
New York: Norton. Chapter 5 of this book discusses some of the evidence that
humans come equipped with genetic predispositions to learn intuitive physics,
biology, and psychology.
Dennett, D.C. 1991. Consciousness
Explained. Boston: Little, Brown. The discussion of the boundaries of selves
is drawn from Chapter 13 of this book.
Gazzaniga, M.S. 1998. The split
brain revisited. Scientific American 279(1):50--55. A review of studies on
patients whose separated cerebral hemispheres act as two semi-independent selves.
Gardner, H. 1993. Multiple Intelligences:
The Theory in Practice. New York: Basic Books. This book discusses evidence
for the existence of semi-independent intelligences, such as logical-mathematical,
linguistic, spatial, musical, and so on.
Reading on More Advanced or Specialized
Topics
Elman, J.L., Bates, E.A., Johnson,
M.H., Karmiloff-Smith, A., Parisi, D., & Plunkett, K. 1996. Rethinking
Innateness: A Connectionist Perspective on Development. Cambridge, MA: M.I.T.
Press. This book reviews several human developmental sequences and argues that
they reflect powerful learning capacities rather than detailed genetic specifications.
Kempermann,G., Kuhn, H.G., & Gage,
F.H. 1997. More hippocampal neurons in adult mice living in an enriched environment.
Nature 386:493--495. One account of how environment can influence brain growth.
Ramachandran, V.S. 1995. Anosognosia
in parietal lobe syndrome. Consciousness and Cognition 4:22--51. A further
discussion of the left hemisphere as the story-maker that imposes consistency
on the world, whereas the right hemisphere contains a "questioning" mechanism
that monitors anomalies and discrepancies.
Bouchard, T.J. 1994. Genes, environment
and personality. Science 264:1700--1701. A brief review of evidence that genetic
factors influence behavior.
Markus, H.R., & Kitayama, S.
1991. Culture and the self: Implications for cognition, emotion, and motivation.
Psychological Review 98(2):224--248. A discussion of the cultural relativity
of the construal of self as independent versus interdependent.
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