BigPicture ISSUE 4
Now you see it...
Optical illusions An invisible gorilla?
such as this help
us understand how
the brain works.
Brain power. Find out on page 3.
The human brain may be the most
complex structure in the universe.
It is so powerful that it is has blossomed; and the genetic
attempting to understand itself, revolution has allowed us to
through research. probe the function of individual
genes and proteins.
The task is daunting. Some
neuroscientists say that if the These techniques are shedding
brain were simple enough to be light on the very essence of
understood, we would not be human life – how we feel, how
clever enough to understand it. we think and how we act. Even
the most difﬁcult question of all,
Yet the nature of human
the nature of consciousness,
existence has fascinated us
is beginning to be unravelled.
for centuries. It used to be
philosophers who held sway While exciting, these
on the nature of human life, developments also raise unease.
the mysteries of consciousness, Can we really see ourselves
and other Big Questions. simply as ‘biological computers’?
If we understand the basis of
In the past 20 years, though, a
our mental self-image, or identity,
battery of new techniques has
can we (and should we) seek to
opened up new ways of exploring
change ourselves into something
the brain. Functional imaging
else? And if our actions are just
allows us to watch the brain in
biology in action, how responsible
action; our understanding of the
can we be for what we do?
biochemistry of nerve function
FIND OUT MORE
Vision, memory and how our eyes play tricks on us 2–3
Mood, emotions, personality and feelings 4–5
Consciousness and self-identity 6–7
Understanding other people (and ourselves) 8–9
How free is free? Controlling our actions 10–11
Real voices: Life with synthaesthesia and schizophrenia 12–13
New knowledge, new issues 14–15
The big picture 16
Learning and memory
The brain structures, neurons
and even molecules and genes
associated with memory are
beginning to be identiﬁed.
We are in many ways the sum of our
experiences. How we act and behave
depends not just on what is happening
The mind’s eye to us now but also on what has
happened to us in the past. We learn
Vision is our most crucial sense. We rely and we can make memories.
on it for survival but just how reliable is it?
Nearly all animals can learn. A simple
It is tempting to think of our eyes as mini-cameras form of learning is association – some
constantly ﬁlming the outside world. In fact, vision is kind of sensory stimulus is ‘remembered’
nothing like that. The seamless view of the world is and an animal’s behaviour changes the
an illusion created by the brain after it has dismantled next time it encounters that stimulus.
the input it receives from the eyes. The classic example is provided by When a nerve impulse (green) arrives at the end
For a start, we do not look at a scene in a steady Pavlov’s dogs, who were given food of a neuron, neurotransmitters ferry the signal
way. Instead, our eyes constantly ﬂicker back and every time a bell rang. Eventually, they across the synapse (pink), setting off a new
began to salivate in response to the action potential (blue). Signals are also sent
forth (involuntary movements known as saccades), back to the original neuron (yellow, top) so that
scanning scenes in detail. From this constantly bell on its own.
the next time a nerve impulse arrives (bottom)
shifting input, the brain builds up a coherent mental Human memory is more complex – the second neuron reads more strongly.
picture corresponding to a scene. in fact, we have several different types
We now know that neurons in our brain specialise of memory, involving many parts of STRANGE TIMES
in recognising particular aspects of a scene, such the brain (see box, below left).
as edges or dots or motion. Each neuron has a Making memories Some people with brain damage,
‘receptive ﬁeld’, an area around it that is sensitive But what exactly does a ‘memory’ or by a quirk of fate, lack a very
to its favoured stimulus (like a detector attached to look like in the brain? Again, it is speciﬁc mental function.
a security light, which can detect movement within difﬁcult to liken it to anything everyday Blindsight
a particular area of ground). such as a photograph in an album. Remarkably, some patients have
Then, in a computational task of staggering Memories are hard to pin down, as no conscious vision but can still
complexity, the brain integrates all these signals to they involve a constellation of neurons point at a coloured dot on a screen
create a visual impression of the outside world. connecting together in different patterns. when forced to guess. This suggests
Putting away the memory of Christmas that we can ‘see’ things without
Pay attention being consciously aware of them.
Another key difference between the visual system day is produced by millions of neural
and a camera is the phenomenon of attention. brain patterns ﬁring: some for the Synaesthesia
There is so much going on in the world that the brain taste of Brussels sprouts, others for Some people don’t just hear sounds
has to ﬁlter out unnecessary input. One way it does a favourite carol. The pattern remains – they see them too (see page 12).
this is by focusing on (or ‘attending’) to a small area after the stimulus disappears and a
memory is born. Prosopagnosia
at any one time. People with prosopagnosia
We are not very aware of this, partly because our In terms of mechanisms, memory making are unable to recognise faces,
peripheral vision is sensitive to movement, so if is thought to depend on neurons suggesting that there is a ‘module’
something noteworthy happens there we are quick to strengthening their connections to one in the brain speciﬁcally dealing
notice. But it means we take in much less of a scene another – ‘remembering’ that they have with face recognition.
than we might imagine. been in touch before (see ﬁgure above). www.ritsumei.ac.jp/~akitaoka/index-e.html
A nice example is a study in which volunteers were
asked to watch a videotape of people playing
basketball. They were asked to count the passes
made by one of the teams. Afterwards they were
asked if they had noticed anything unusual.
Fixated on counting, almost half failed to spot a woman
dressed in a gorilla suit who stopped to face the
camera, banged her chest and walked off.
The other big difference between the brain and a
camera is that the brain guesses more. When
presented with incomplete information, it ﬁlls in the
gaps, making assumptions about what should be
there given the rest of the visual input it is receiving. Optical quirk – www.ophtasurf.com/en/bestillusions5.htm
This optical illusion illustrates how our perception can be tricked –
This ﬁlling in can be useful. The visual system is in this case into believing something is moving. Optical illusions
often trying to extract patterns. So when it ﬁnds one have told us much about how the brain interprets
but with a bit missing, it ﬁlls in the missing space, so scenes, for more details (and illusions) see... ON THE WEB
we get a complete coherent picture. But it sometimes
leaps to the wrong conclusion. Can we believe our www.wellcome.ac.uk/bigpicture/thinking
eyes? Not always.
SEPTEMBER 2006 | 3
WHY DO I THINK
We sometimes think of a brain as a powerful computer. But it is much more than
that. Our brains are also home to our feelings, moods, personalities and character.
Courage is not found in the heart but in our brain’s neural networks.
Memories are made of this long-term behaviour and decision-
Emotions As well as preferentially focusing on making. So our choices depend in
We are emotional creatures. emotional stimuli, we also remember part on our past feeling states.
The brain is not just a logic them better. We tend to remember
machine, but also handles not the mundane but the events
emotions – some of the most that are emotionally charged – the
good or the bad. Again, memory
Emotion and reason are often
thought of as enemies – a battle FAST
powerful drivers of human
enhancement seems to depend on
between cold, hard logic and
irrational, emotional decision-making.
activity in the amygdala.
Emotion is important to how we In fact, though, emotional responses
Sometimes, though, people do not nerve ﬁbres in
experience life. Love, fear, anger, may enhance our decision-making brain = 150 000
want to be reminded of emotionally
disgust are central to human ability, for example by helping us to to 180 000 km
charged experiences. People with
experience. This handful of raw make value judgements about people (enough to
post-traumatic stress disorder
emotions, in different combinations, based on their facial expressions or go round the
(PTSD) suffer from unwanted
adds spice to our existence, deﬁnes because of an awareness of our Earth about
ﬂashbacks and intrusive memories of
many of our goals and inﬂuences current bodily state. four times)
their trauma. Interestingly, creation
of traumatic memories depends on
In their crudest form, emotions help a particular neurotransmitter
survival. Fear and disgust drive us
away from possible sources of harm,
(noradrenaline), and a drug that blocks
its action – propanolol, more usually WHAT GOVERNS
such as predators or rotten food;
love helps us reproduce. They have
used to slow the heart – can prevent
traumatic memories being laid down.
There is interest in using this as a Our mood, or predominant emotion, is governed by
a profound impact on us, affecting
drug to treat, or even prevent, PTSD. several neurotransmitters produced in our bodies.
almost all aspects of our behaviour
and thinking. Serotonin enhances mood by reducing depression
Feelings, nothing more
than feelings and anxiety. Antidepressants that increase serotonin
One impact is on attention (see
Neuroscientists see emotions as levels are now widely used to treat depression.
page 3). We detect emotional stimuli
well-described and consistent brain Interestingly, low serotonin levels have been found
– faces with positive or negative
responses. They translate into in suicide victims.
expressions, or spiders and snakes
– much quicker than neutral ones. subjective experiences we know as Dopamine, nicknamed ‘the pleasure chemical’,
feelings. These derive in part from promotes a feeling of bliss. This explains the
Oddly, though, functional imaging
the physiological changes created attraction of alcohol, nicotine, and drugs such as
(see page 6) has shown that the brain
by the emotional stimuli, which are cocaine, all of which increase dopamine levels.
also reacts to emotional stimuli before
registered by sensors of the body’s
the nature of stimuli has been explicitly Playing sports makes us feel better due to the
internal state (internal organs,
recognised, or even without any release of noradrenaline, another feel-good
energy levels etc.).
conscious recollection that we’ve chemical. Pleasure is also increased by endorphins,
seen something scary (for instance). It is likely that the brain systems the body’s natural painkillers, which are also
handling emotions are not the same released during exercise.
The key brain region here is the
as those responsible for feelings.
amygdala, which receives visual Other chemicals, such as GABA and histamine,
For example, some people with
input independent of the main vision may also inﬂuence mood. Our ﬁnal mood is governed
amygdala damage do not show
processing areas of the brain. If it by complex interplay between all these chemicals,
emotional responses but still
detects frightening stimuli, it sends with each chemical’s level being modiﬁed by
messages to other parts of the brain, factors such as heredity, environment, lifestyle –
triggering a series of responses – Another distinction is that feelings and even diet.
making us ‘frightened’. seem to have more inﬂuence over
4 | BIG PICTURE 4
Can personality be studied in a reliable way?
FAST We all recognise that people are unique, with distinct
FACT personalities. We also have an urge to categorise, and
numerous approaches have been taken to analyse
personalities and draw out common themes.
in cerebral Personality is sometimes broken down into a number of
cortex = qualities. The most common tests focus on four or ﬁve
10–20 billion qualities – like the so-called Big Five:
NUN BETTER: Is happiness actually good for us? A study of (about three
nuns suggests it may be. The nuns had written autobiographies times the Openness to experience Agreeableness
in their 20s. When these were scored for positive or negative
emotions, those most positive lived on average ten years
population Conscientiousness Neuroticism
longer than those expressing the least positive feelings.
of the Earth) Extraversion
Subjects complete carefully constructed questionnaires
Happiness and end up with scores for each of the categories.
A variant of this method is the Myers–Briggs model:
Research has tended to look at the dark side of life – anxiety,
Extraversion vs Introversion
depression and so on. The ﬂipside, happiness or contentment,
Sensing vs INtuition
has been neglected, but is now receiving more attention. Thinking vs Feeling
Money can’t buy me love, sang the Beatles, and it can’t buy much happiness Judging vs Perceiving
either. A little bit extra seems to help, but above a fairly low threshold more These tests seem to be fairly robust – if people do the
money does not add to our happiness (though around the world, a great many test on different days, their scores tend to be very similar
people will be below this threshold). Relative wealth seems to be crucial – and they are not inﬂuenced much by mood.
is there someone better off than us? As Samuel Johnson noted: “Life is a
progress from want to want, not from enjoyment to enjoyment.” Are these measures of value? They can be useful tools
for self-awareness and help people understand and
Similarly, Ghana, Mexico, Sweden, the UK and the USA all share similar life interact with others. They may also help to identify
satisfaction scores even though average income varies ten-fold between the people susceptible to mental health problems. For
richest and poorest countries. example, psychological measures provide a very good
In 44 countries surveyed in way of picking out people likely to suffer from post-
2002, family life provided the traumatic stress disorder after a traumatic incident.
greatest source of satisfaction. One problem with such personality tests, though, is that
And it’s good for us too: individuals can end up being pigeon-holed into a certain
married people live on average ‘type’ or behaving in ways they think are expected of them.
three years longer and enjoy
greater physical and psychological health than the unmarried. More generally,
the extent of our social network is the best predictor of happiness.
Other important factors include satisfaction with work and working conditions
and extent of choice and political freedom in the society in which we live.
Can we do anything about our state of happiness? Good fortune can raise our
mood temporarily, but we gradually return to some kind of baseline, suggesting
that we may have some inbuilt happiness level. If we do want to be happy, it is
best to concentrate on social connections and fulﬁlling work rather than
the pursuit of wealth – or you could move to Bhutan, where the King recently
announced that his nation’s objective would be gross national happiness.
Trust me, I’m a scientist
Although we do fall out occasionally, human
society is notable for its degree of cooperation SEEING THINGS: The Rorschach inkblot test, one of the earliest
personality tests. People look at inkblots and quickly say what
between individuals. they think they show. But analysis of the test is subjective too,
Cooperation presents a difﬁculty for evolutionary as interpretation varies with the psychologist.
theory, which at its simplest suggests that individuals
should just look out for themselves. More sophisticated Mental health – broadly speaking, three kinds of mental health disorder exist.
analyses, though, show that helping others can bring • Mood disorders – Depression, bipolar disorder (manic depression).
you beneﬁts – the phenomenon of indirect reciprocity – Long-term disturbance to mood.
you help somebody, somebody else helps you.
• Anxiety disorders – Post-traumatic stress disorder, social phobia,
This analysis can explain how factors such as reputation, phobias, obsessive–compulsive disorder. States of excessive anxiety
perceived moral character and other aspects of social interfering signiﬁcantly with daily life.
communication can develop. • Personality disorders – Antisocial personality disorders, borderline
We know a little about the brain systems responsible for personality disorder. Inﬂexible and problematic patterns of thought
these phenomena. Logical reasoning plays a part but is and behaviour. Less consensus on their medical nature.
not the whole story. One interesting player is the hormone Find out more at ON THE WEB
oxytocin, which encourages bonding. When given to
subjects playing a risky investment game, it makes them www.wellcome.ac.uk/bigpicture/thinking
more trusting of their (unidentiﬁed) partners.
SEPTEMBER 2006 | 5
WHO AM I?
We can usually tell when we have spoken and when we have
listened to others. Or whether we have moved our arm or someone
else has moved it for us. Our brains can distinguish ‘us’ from ‘them’.
More philosophically, we also have a perception of
ourselves – our personality and character. That, more
than our physical form, is what we mean by ‘me’. The Greek physician
We have a sense of ourselves occupying our body Hippocrates, who lived
and can imagine an existence outside it. around 400 BCE, was the ﬁrst
Because these impressions are subjective – existing to emphasise the importance
just within our own heads – they are very difﬁcult to study. of the body in generating
Do you feel pain in the same way as I do? Or experience functions such as memory,
the colour red in the same way? thought and reason.
We are beginning to discover how the brain creates He proposed a purely materialist What is consciousness?
these internal impressions, including those of self and account of body and mind in which Philosophers have spent centuries
self-identity. our health and behaviour are debating the nature of consciousness.
governed by four ‘humours’ – It remains a highly controversial
WAYS OF SEEING blood, phlegm, bile and black bile. topic, with plenty of disagreement.
Lower passions such as greed and
Consciousness encompasses feelings
lust must reside in the liver and
Assess people’s behaviour or responses and experience, many of which are
guts, reason in the head. These
under controlled experimental purely subjective (the sensation of
ideas persist – we still speak of
circumstances. taste for example, or ‘the redness
making decisions according to our
of red’). These are known as qualia.
Example: Experiments exploring our heart or our head.
A major problem for science is to
approach to risk.
The philosopher Plato, who lived understand how these experiences
FUNCTIONAL IMAGING during the same period, rejected can arise from the brain’s raw
(e.g. functional magnetic resonance this idea. He believed in the soul. material – the neurons, other types
imaging, fMRI) These competing theories prevailed of cells and surrounding ﬂuids and
Measures brain activity during until the 17th century, when French intercellular ‘glue’ inside our skulls.
particular tasks. philosopher René Descartes (above) Scientists often talk in terms of an
Example: Reveals which areas are active conceived the idea that there is a ‘emergent property’ – something
when we read and comprehend language. total split between the conscious that happens collectively that would
mind and the body – the dualist not have been predicted on the
concept. He believed that voluntary basis of what is known of the
Recording of brain waves through the
thought and movement are the individual units.
scalp; gives clues to timing, locality
and type of brain function.
properties of an immortal soul.
Some neuroscientists call the
Example: Monitoring brain activity The dualist concept has endured for subjective element the ‘hard’ problem
during sleep. centuries. Its success is probably of consciousness. Because it is
because, intuitively, we ﬁnd it hard ‘private’ to an individual, some argue
to accept the idea that ‘mere’ brain that it is not something that we will
Assessing impact of damage to speciﬁc
tissue can produce feelings and ever be able to explain meaningfully.
parts of the brain.
experiences like love, imagination,
Example: Damage to Broca’s area More conveniently, consciousness
dreams and passion.
removes ability to speak. can be likened to awareness –
For ages, scientists were reluctant of one’s self and surroundings. It is
ELECTROPHYSIOLOGY to tackle the issue of mind and sometimes divided into phenomenal
Studying the ﬁring patterns of neurons consciousness because it was consciousness (P-consciousness),
and their response to different chemicals.
either too philosophical or just too an awareness of what is going on
Examples: Understanding role of elusive to study experimentally. now, and access consciousness
neurotransmitters in memory. What actually is ‘consciousness’? (A-consciousness), reﬂecting internally,
ANIMAL STUDIES How can you measure it? drawing on past experience
Links between genes, neurons, brain and and memory.
behaviour can be studied in animals that
can be genetically engineered.
Example: Neuron function in the sea slug;
neural pathways controlling sexuality in
ABNORMAL VERSUS NORMAL
the fruit ﬂy. Neuroscience research has tended to focus on abnormal function –
such as Phineas Gage (see page 2), ‘memory men’, or people with
MODELLING aphasia. While this is still an important element of research, greater
Using computers to model the behaviour attention is now given to studies of the ‘normal’ – what is going on
of neurons acting together. inside the heads of people who are not judged to have any clinical
Examples: Neural networks mimicking problem. This is shedding light on brain function, but also helps us
brain activity leading to epileptic seizures. to judge when something should be classiﬁed as ‘abnormal’.
6 | BIG PICTURE 4
The science of Unconscious vision
consciousness Vision is so important to us that it tends to dominate research on
consciousness. To get at the heart of a conscious experience, we need to
Consciousness is one of the last great mysteries compare the brain’s response to consciously and unconsciously perceived
of modern science. stimuli. But how do you have an unconscious visual experience?
Zoom into the brain, and you see a dense network of The usual trick is to apply backward masking – a visual stimulus is shown
cells. The vivid quality of our conscious experience, our to a subject very brieﬂy and is then replaced by a strong second stimulus.
emotions, imagination, dreams and mystical experiences, This dominates the conscious visual response, ‘masking’ the original stimulus.
are all underpinned by a ﬂurry of electrical activity, neurons Subjects cannot say, or even guess, what it is they were shown.
ﬁring and interacting in different sets of patterns. Every
aspect of the mind, most neuroscientists now believe, However, psychological tests and brain imaging shows that they have
can be explained in mechanistic terms. registered the image. If it was an angry face, they react much more strongly
when shown it again than if they are seeing it for the ﬁrst time – even though
Francis Crick was one of the ﬁrst to propose that they do not ‘know’ they have seen it before.
consciousness or awareness is underpinned by brain
activity alone – what he called his ‘astonishing hypothesis’.
In the 1960s, he argued that neuroscientists must search
out the neurons that ﬁre speciﬁcally during conscious
moments – the so-called neural correlates of
Of course, many neurons are active when we are conscious
but that doesn’t mean they are necessarily contributing
to a conscious experience. One way to narrow the
search is to compare a sensory system operating with
or without conscious awareness (e.g. by using backward
masking; see right). An alternative is to examine the impact
of different types and doses of anaesthetics, which can
selectively remove aspects of conscious experience.
Although not certain, there is a growing consensus that
consciousness is not located in one speciﬁc part of the
brain but is distributed around the brain in a kind of
network. Some liken it to a virtual ‘workspace’ that
draws upon unconscious neural activity all around the
brain, assimilating our conscious view of the world.
This view is a little like a security guard using security
cameras to monitor what is going on around a building.
This is curiously similar to an early metaphor for
Sleep and consciousness
consciousness, in which a tiny man – the homunculus – During sleep, our brain slips into autopilot. The key change,
sat in the brain absorbing information from the outside it seems, is the loss of communication between different areas
world and deciding what the body should do. of the brain.
Each day, when we fall asleep, we depart consciousness. The sleeping brain
has long puzzled scientists, who have noticed that even though consciousness
fades the brain remains active.
Vivid dreams are similar to a ‘virtual reality’ experience. Intensely visual dreams
light up the visual cortex, nightmares trigger activity in the amygdala, and
the hippocampus ﬂares up from time to time to replay recent events. The
pathways that carry signals from the auditory cortex are also active, as are
the motor areas. But despite this symphony of brain activity, people still have
no conscious experience.
Scientists now believe they can explain why. With the onset of sleep, the
connections between brain areas weaken and the information, though present,
is not integrated. So, when a powerful magnet is used to stimulate the brain
speciﬁcally in the premotor area, activity spreads to the rest of the brain when
people are awake but remains locally conﬁned when they are asleep.
A similar uncoupling could explain how anaesthetics work.
Recent studies suggest that neural activity does not stop,
but the brain no longer integrates information from different
areas of the brain.
Sleep yourself better – Want to improve your dance moves? Finish
a crossword? Then take to your bed. Far from shutting off, the brain
uses sleep as a time to lay down memories and replay the day’s
activities. We may not know it, but we wake up better prepared for
the world than when we went to sleep. Find out more at
DIVISION OF LABOUR: A 1930s view of the body. ON THE WEB
The technology may look antiquated, but the idea
of ‘division of labour’ in the brain is still valid. www.wellcome.ac.uk/bigpicture/thinking
SEPTEMBER 2006 | 7
WHO ARE YOU?
As social animals, we interact with other people,
cooperating, negotiating and occasionally confronting.
Our success as a species owes a
lot to our ability to work together –
Face the facts
fossil evidence suggests that early We draw important information from in children; it improves as children get older,
humans were a tasty treat for people’s faces and facial expressions. dipping slightly at adolescence. Younger children
predators. As a collaborating pack, are generally less able to pick up subtle facial
we were safer and could become It is said that the route to a person’s soul is cues, one reason why their behaviour is less
hunters rather than hunted. through their eyes. There is much truth in that, inﬂuenced by others.)
as we extract considerable information about
Collective action depends on people’s moods and feelings from their faces, There are some suggestions that, as well as
effective communication. Although particularly the eyes. the stereotyped major expressions, there are
we have developed language, we many ‘micro-expressions’ that convey meaning.
also draw important non-verbal We seem to have speciﬁc face-recognition The brain picks these up subconsciously.
information from others – reading modules in the brain, emphasising their
facial expressions, for example – importance to us. So when we recognise CHARLES DARWIN PROPOSED
and draw inferences about people’s someone it is usually through their faces and
THAT FACIAL EXPRESSIONS WERE
intentions and motivations. not, for example, their body posture. Further
evidence comes from people with COMMON TO ALL HUMANITY
If we have problems with these prosopagnosia (see page 3) who speciﬁcally
forms of social communication, we cannot recognise faces. Even sheep seem to Expressions give away information about us,
can have great difﬁculty functioning recognise other sheep by their faces. but so does the basic structure of our face.
as part of society. Sex, age and ethnicity can all be assessed
The presence of a face-recognition module from faces. A masculine face is very different
could also explain why we tend to ‘see’ faces from a feminine one. Even our sense of beauty is
MIRROR, MIRROR in, for example, toast or on the moon – the strongly linked to facial features – a symmetrical
brain interprets a face-like pattern of light and face is usually seen as more attractive.
The discovery of mirror systems shade as a genuine face.
has helped us understand the Through the ages, people have tried to take
Charles Darwin proposed that facial this further and infer character from faces.
planning and imagining of actions.
expressions were common to all humanity – Was there a ‘criminal face’ that could be
When we move to strike a tennis even remote populations laugh the same way used to identify possible miscreants? Despite
ball, for example, our actions we do. We can all tell when someone is happy a huge amount of work, no convincing links
are guided by the brain’s motor or sad or angry from the expression on their have ever been found.
control systems. face. (Although this ability is not well developed
Recently, it has become clear that
these same systems are also
active when we imagine making
an action in our head (reliving a
perfect cross-court volley, for
example). And, remarkably, they
also light up when we watch
someone performing an action.
The key difference is that the
levels of activity are lower than
when we actually perform the
action – so muscular contraction
is not actually triggered. Because
the systems reﬂect the ‘real’
activity, they are known as
The system is extraordinarily
speciﬁc. Mirror systems ﬁre
when someone sees a person
making an arm movement, for
example, but not when they see
a robotic arm move. It is
possible that this activity allows
us to put ourselves in others’
positions, experiencing (but to MR EXPRESSIVE HEAD:
a lesser degree) what they are We draw much information
about people’s state of mind
experiencing. They may therefore from their facial expressions
help us to infer the intentions and how a small change
of others. can make a big difference –
see back page.
8 | BIG PICTURE 4
You or me?
If our grasp of ‘us and them’ goes wrong, MIND THE GAP
we can have considerable problems in life. Humans have an uncanny ability to put themselves in the
position of others.
Most of us take for granted that we can tell the difference
between an action we have generated ourselves and Young children can be horribly selﬁsh. They want things for themselves
one forced on us by another. And most of our social and are not interested in sharing. Partly this is because they lack the
interactions with other people are not consciously ability to appreciate what other individuals are thinking and feeling.
thought about. But if our brains are not adept at these This develops gradually during childhood.
activities, life can be very challenging.
Being able to understand the feelings and motivations of others, being
People with schizophrenia, for example, show several able to put yourself in other people’s shoes, is known as theory of
distorted ways of thinking during psychotic episodes. mind. It is the basis of what we know as empathy – appreciating what
A common symptom is to believe that one’s actions are others are feeling and how our own behaviour may impact on them.
being controlled by external forces. In brain scans, this is
It is likely that people’s capacity for empathy varies. We can probably
apparent as activity patterns characteristic of externally
identify people whom we feel are particularly empathic (or seem to lack it).
applied (rather than internally generated) movements.
(An odd consequence of this is that, during a psychotic In some conditions, theory of mind seems to be very badly affected.
episode, people with schizophrenia can tickle themselves: A common feature of autism, for example, is an inability to appreciate
they do not perceive the hand doing the tickling as what others are thinking and feeling, or to appreciate the impact of
their own.) one’s actions on others. As a result, people with autism generally lack
social skills, and have to be taught how to behave in social situations
Similarly, people with schizophrenia will sometimes hear
where most of us would behave naturally, relying on unconscious
internal voices, urging them to do things. Brain imaging
again shows brain activity corresponding to external
sounds, not internal dialogue.
A third common symptom in people with schizophrenia
is paranoia, a belief that people are following you or
looking at you all the time. This appears to be an error
in processing information from others – a casual glance When people scratch their nose, does it mean they are lying?
ignored by most is interpreted as evidence of a deep Popular psychology is full of accounts of ‘body language’. If I cross my arms,
interest and desire to cause harm. I’m being defensive; if I pull my ear, I’m likely to be lying; if I avoid your gaze,
It is possible that impaired pick-up of social cues also I’ve got something to hide.
underpins other forms of behaviour disorder. People with The basis of body language was in animal communication. Without language,
antisocial personality disorder (psychopathy) seem less animals need ways to convey information to one another – and use parts of
able to identify fearful expressions, so will be less able to their bodies in imaginative ways to do so. Faces are again important, but so
tell that their behaviour is having a negative impact on too are, for example, gestures of submission. Mating relies heavily on signals
people. Some symptoms of autism, too, seem to be linked of intent, receptivity or rejection, often leading to elaborate rituals.
to defective recognition of social cues (see above right).
The popularity of studying body language in humans owes much to
Desmond Morris. He argued that information from animals could be
extrapolated to humans. The scientiﬁc value of this area, social anthropology,
has been questioned by many neuroscientists.
The neuroscience of body language has been studied much less well than
responses to faces. But it does appear that the brain can recognise particular
body postures and that recognition occurs early during processing of a
scene (as is also true of face recognition). There could be brain modules
speciﬁcally for body perception.
The body language responses studied to date seem to be closely linked to
the brain’s emotional responses. So seeing someone showing signs of
SCHIZOPHRENIA: Coloured positron emission tomography distress ﬁres up our amygdala. This cues behaviour needed to escape from
(PET) scans of sections through a healthy brain (left) and a
threatening stimuli (such as the need to run away very fast).
schizophrenic brain (right). The colours show different levels of
activity within the brain during an attention test. Red shows high We also seem to be particularly sensitive to bodies in motion – though as
activity, through yellow and green to black (very low activity). The
schizophrenic brain shows much lower activity in the frontal lobes.
artists through the century have proved, our emotional responses to still
images of bodies in peril are powerful and quick to appear.
Faces reveal much
inner thoughts and
feelings. We also
from body posture.
What might these
people be thinking
SEPTEMBER 2006 | 9
WHY DO I DO We usually like to believe
WHAT I DO?
Where naughty treats are concerned,
though, we ﬁnd it convenient to think
that we are free agents,
capable of informed choice
about what we do.
we are driven by powers beyond
Both points of view are correct, but
it is not always obvious how much
conscious control we actually have.
Even when we think we have made
a conscious choice, this may actually
be an illusion…
Eating and taking part in
sexual activity are essential
for life and for species survival,
so are rewarded with a good
feeling produced in the brain.
Repeating the tasks leads to
a cycle of reward.
Dopamine, a feel-good chemical
is central to this cycle. Alcohol, How much of our behaviour is ﬁxed, There is bound to be interplay between
nicotine, and drugs such as embedded in the neural networks of these factors. We may be born with a genetic
cocaine and heroin all increase our brain? Is it ‘hard-wired’ – set for predisposition to alcoholism but lucky enough
dopamine levels. life – or more ﬂexibly arranged? in our family and social life that we never get
tipped over the edge into dependency.
But why do some substances just Behaviour is complex. No single gene encodes
produce pleasure while others for it, nor does any single event or experience Also, the brain itself is not set in stone.
are addictive? The likely answer control it. Although we can control some It develops through childhood, goes through
is that in addiction, substances aspects with our own willpower or volition, massive change at adolescence, and reaches
trigger permanent changes to the in the end our behaviour arises from an maturity in our early 20s. Even then the
dopamine/reward pathways, which intricate interplay between our environment, brain retains signiﬁcant plasticity – it learns
lead to cravings. In effect, drug our genes and us. and adapts. So if we practise tennis we
intake goes from being a voluntary get better at it.
activity, under conscious control, to OUR GENES EVEN HAVE SOME So exactly how much of our behaviour can
an unconsciously driven desire, with
CONTROL OVER BEHAVIOURS THAT be modiﬁed, and how much is inborn or
different brain areas taking over. ﬁxed by our upbringing? It is hard to say.
WE ARE UNAWARE OF.
Pinpointing exactly how each With humans such a debate is risky, as
substance works can help identify Science has shown that many patterns of the notion of ‘hard-wiring’ can be used to
ways to block the addiction cycle. behaviour, including alcoholism, criminality support racist or sexist views or other forms
and homosexuality, have some genetic of bigotry. On the other hand, in Steven
inﬂuence. Our genes even have some control Pinker’s famous phrase, we are clearly not
over behaviours that we are unaware of – ‘blank slates’ either.
such as hand clasping (people tend to
intertwine clasped hands with either the
right or the left side uppermost). FAST
In the case of alcoholism, genes may FACT
code for certain receptors that bind
chemical messengers in the brain, or for
enzymes involved in breaking down alcohol.
Our social and cultural upbringing every second
may also affect our alcohol consumption – of our lives
our parents may be teetotal, for example.
10 | BIG PICTURE 4
A BRIEF Morality tales
HISTORY Morality is a social sense of what is right
or wrong. One of the most hotly contested
Functional imaging has shown that the
superior temporal sulcus, as well as the
OF MENTAL questions is whether our brains come with prefrontal cortex, is involved in making moral
ILLNESS some sense of morality already built in or
whether it is something we have to learn.
judgements. Psychological tests can also
be used to see how people respond to moral
dilemmas, or questionnaires examining their
Pre-history (e.g. Stone Age) Our morals differ according to our sex,
moral reasoning (i.e. how they would respond
Trepanning (drilling holes in the skull) religion and culture. They also change with
in different situations). These again show that
is used to get rid of evil spirits. age. Very young children can’t tell right from
people with personality disorders are less
wrong. In toddlers, morality is based around
Approx. 400 BCE able to identify the morally most appropriate
Hippocrates treats mental illness
themselves. With age, morality shifts towards
courses of action.
as a problem of the body rather than peer-group values and eventually moves
a punishment sent by the Gods. towards consideration of the wider social group.
1377 Morality is, of course, deeply rooted in the
Opening of The Bethlem values held collectively by society. Philosophers
Royal Hospital in London, and theologians have debated for centuries
also known as Bedlam. whether absolute moral values exist, or
1600s whether they are reﬂections of what is socially
Chains, shackles and imprisonment acceptable. What was morally acceptable to
are largely used to restrain and control the ancient Greeks – slavery, for example –
the mentally ill. may not be seen as OK today.
1850s Neuroscience is helping us to understand
Asylums built. the biological basis of human morality.
1870s Examination of people with brain lesions A classic morality study is the ‘trolley problem’.
Normal ovaries are removed to treat (damage) shows that people with early You are presented with a dilemma: a runaway trolley
‘mental madness’ and ‘hysterical damage to the prefrontal cortex do not is about to kill ﬁve people. Should you throw a switch
to divert the trolley onto a spur on which it will kill one
vomiting’ in some women. develop normal moral responses. They lie person and allow the ﬁve to survive? You are then
Early 1900s and cheat without feeling guilt or regret. given the same scenario, without the spur but with
Psychoanalysis inspired Brain scans of people with antisocial the option to throw a man on the track to save the ﬁve.
Should you throw him? People usually say ‘yes’ to the
by Sigmund Freud, personality disorders show that psychopaths
ﬁrst dilemma, and ‘no’ to the second. Interestingly,
Carl Jung and others. have less grey matter in the prefrontal cortex fMRI studies show that different parts of the brain are
than normal people. active as the subject considers the two scenarios.
Swiss psychiatrist Eugen Bleuler ﬁrst
uses the term ‘schizophrenia’.
Patients with shell shock are Many conditions with a genetic link affect the brain or behaviour – including autism, schizophrenia
counselled – the precursor of and bipolar disorder (manic depression). There are a wide range of disorders, however, showing
modern treatment for post- distinctive alterations in behaviour (including the examples below). Studies of people with these
traumatic stress disorder. disorders can shed light on brain function.
Lobotomy (surgical removal
of part of the brain).
Electro-shock therapy for
schizophrenia and manic depression.
Lithium for psychosis and
manic depression (now
called bipolar disorder).
REFLEX: Tim Howard, goalkeeper for Manchester FRIENDLY FACE: A young girl with the typical
The ﬁrst anti-psychotic drug,
United and the USA, has Tourette syndrome. appearance of Williams–Beuren syndrome.
Thorazine, for psychosis. Rex Features The University of Utah, Genetic Science Learning Center
Behaviour therapy for phobias. Tourette syndrome Williams–Beuren syndrome
• People with Tourette have characteristic, (Williams syndrome)
semi-involuntary tics such as sudden, • Children with Williams–Beuren syndrome
Librium and Valium
for nonpsychotic anxiety.
rapid movements (e.g. blinking or snifﬁng) have a characteristic elﬁn-like face, and
and verbal tics (e.g. shouting or swearing). tend to have a degree of developmental
1970s–1980s delays and some learning disorders.
A move away from asylums, • People seem unable to suppress
mental institutions and hospitals unconscious thoughts or reﬂex-driven • They frequently have a love of music and
to community-based healthcare. movement, possibly due to disrupted are polite and friendly by nature, often
communication between the prefrontal being overly trusting of strangers.
‘Selective serotonin re-uptake cortex and other areas of the brain.
• Recent research suggests the syndrome
inhibitors’ for depression. • Recent research has shown that a gene is caused by loss of a chunk of
1990s called SLITRK1 that is involved in brain chromosome 7, which typically removes
New generation of anti-psychotic development is disrupted in a small 28 genes.
drugs for schizophrenia. number of cases.
SEPTEMBER 2006 | 11
The brain works in mysterious ways. Some people experience life in very different
ways because of quirks in the way their brain operates. We spoke to two such people
about the impact of unusual brain function – synaesthesia and schizophrenia –
on their lives.
SYNAESTHESIA is an unusual condition SCHIZOPHRENIA is typiﬁed by unusual
affecting the senses. Typically two senses ways of thinking; common symptoms include
become mixed – for example, sounds give hallucinations or internal voices, delusions and
rise to a visual experience, or sight is linked to paranoia. Symptoms vary signiﬁcantly, however,
touch sensations (someone with vision–touch and the condition overlaps with bipolar disorder
synaesthesia feels a touch if they see someone (manic depression). It tends to emerge in late
else being touched). Its causes are unknown, adolescence. Its origins are uncertain; genetic
but a genetic contribution is possible. The and environmental risk factors (e.g. poor maternal
symptoms may stem from cross-wiring in the nutrition) have been identiﬁed. Roughly translated,
brain, so that nerve impulses triggered by one schizophrenia means ‘shattered mind’; contrary
sense activate brain areas responsible for a to popular perceptions, however, it is not
different sense. associated with multiple personalities.
WHAT ROLE DO YOU THINK YOUR
Julie Roxburgh is a retired music BRAIN HAS IN YOUR CONDITION?
teacher. When she hears sounds she
sees them as colours: a condition known JR It could have something to
as sound-to-colour synaesthesia. do with the connections in
your brain – the wiring as you
What are the most signiﬁcant might call it. I know I certainly
features of your synaesthesia? don’t have any control over it.
JR It is very hard to describe. It’s as if I have a
big screen in front of me, and when I hear sounds
they appear on the screen as colours and shapes.
Sometimes they are moving and they appear in Do you consider your condition
different areas of the screen every time. I am a
trained musician and I used to teach oboe and
an illness or a disability?
clarinet, so I know what colour to expect when JR I don’t think it could be called a disability
I hear different instruments. The low notes on a compared to the dreadful problems that other
clarinet, for example, are a blue-black colour and people have. However, it does create difﬁculties.
the high notes are a murky white. Other sounds, Society is not designed for synaesthetes. I can’t
such as trafﬁc, can appear differently every time. go to places where there is a lot of noise. Music
in shops is so distracting.
How does it affect your life?
JR I can’t always differentiate between my senses
How do people react when you
– whether I am hearing something or seeing it. tell them about your condition?
When my alarm clock rings, I see brass-coloured JR Most people ﬁnd it hard to understand.
bubbles and white lines. It’s quite disturbing ﬁrst Describing it is like trying to explain colour to
thing in the morning when you are waking up. someone who has been blind from birth. Equally,
Seeing colours and shapes all the time muddles up I can’t think what it would be like not to be
my thought process, especially when I am tired. synaesthetic. My husband is a composer and I
can’t imagine how he hears in his head the sounds
he wants to write down, yet doesn’t see them.
One person’s view
of numbers, which What do you think the origins
are associated with of your condition are?
JR My brother, my mother and my son are all
synaesthetic and I think my granddaughter might
be. So there could be a genetic link.
12 | BIG PICTURE 4
WHAT ROLE DO YOU THINK YOUR
BRAIN HAS IN YOUR CONDITION?
EJ There seems to be a tendency
to release too much or not enough DO YOU FEEL COMFORTABLE TELLING
of certain chemicals from time to PEOPLE ABOUT YOUR CONDITION?
time. You start feeling anxious and EJ Yes, and I believe it is important
get very powerful emotional charges. to speak out. There are many people
As time goes by you begin to suffering in silence because of ignorance
recognise the occasions when you and prejudice. More people like myself
need to do something about it, such need to tell others what it’s like.
as talk to your psychotherapist.
Edward Jones, 58, is a volunteer What treatment have you had? (by Chris Nurse)
with the mental health charity Rethink. EJ The psychiatrist I saw after I was ﬁrst diagnosed in two halves
saved my life. He was able to gain my trust and I felt illustrating the
He was diagnosed with schizophrenia able to tell him exactly how I was feeling. Now I see decline into mental
at the age of 21. a psychotherapist whenever I feel the need to talk
illness and the
to someone. normal perception.
What are the most signiﬁcant
features of your condition? How do you feel people with
Edward Jones Anxiety, paranoia and depression schizophrenia are portrayed in
are features. But on a day-to-day basis delusions are the media?
the biggest problem I have to deal with. My condition EJ When a person with schizophrenia commits a violent
distorts perception so I make sure to keep talking to crime the media tends to give it so much attention.
people and asking them what’s real and what’s not. But as far as I know, the statistics show that fewer
In very severe cases of schizophrenia you can’t people with schizophrenia commit crime than ordinary
actually make the distinction. people. In a way, I don’t really blame the media for this
because a lot of people like me aren’t speaking out.
How does it affect your life?
EJ I sometimes feel anxious and depressed. I go What do you think the origins
over and over what people have said to me and put of your condition are?
a negative interpretation on it. However, experience EJ I’d say the causes are genetic. My mother
has shown me that these feelings won’t last forever had schizophrenia. She twisted everything you
and that I just have to wait for them to pass. said to make it seem hostile. She became angry
very quickly and thought she heard voices.
Are you responsible? ONLINE ACTIVITY
It was a high-proﬁle murder case… What do you think? The activity is supported by background
The accused had brutally slain In this activity, students are encouraged material, including the two podcasts –
to think about the brain works, how it which can be listened to on the website
controls behaviour and whether we are or downloaded onto an MP3 player –
His defence? He’d been suffering always fully responsible for our actions. plus support notes for pupils and teachers.
from a brain tumour at the time, Using specially commissioned podcasts,
the physical changes in his brain students can also consider how science Full details can be found at
causing him to become more is reported in the media. www.wellcome.ac.uk/bigpicture/thinking
aggressive and impulsive, making
him less responsible for his actions.
The press had a ﬁeld day…
This issue’s classroom activity is based
around two podcasts. They are news
reports of the court case – produced in
completely different styles.
IT ALL MEAN?
We are rapidly gaining a much better understanding of the brain and how it operates. We are
beginning to see how our thought processes and actions are shaped by activity in the brain.
This new knowledge is exciting, but presents us with many challenges. And tools
and therapies for use in medicine or research could equally well be applied socially
for other uses. How are we going to manage these ethical quandaries?
If a lot of our behaviour is outside our conscious
control (or feels as if it is), can we always be held
responsible for our actions?
Our legal system (and many other aspects of society) are
based on the idea that we are ‘free agents’, able to decide
for ourselves how we behave.
But how much freedom do we actually have to control our
behaviour? Some brain responses are not under conscious
control. Sometimes, even when we think we are making a YOU ARE THE JUDG
conscious decision, our brain has already made an E
unconscious one. Or our conscious and unconscious
wrestle for control of our actions.
Our genetic inheritance will affect our brain and behaviour,
as will the environment we experience in the womb, and the CASE STUDY 1 CASE STUDY 2
way we are brought up. By the time we are adults, our scope Defendant X Defendant Y
to behave in any way we choose is signiﬁcantly reduced. • Impulsive behaviour runs in • She was brought up on a
his family. deprived inner city estate.
On the other hand, genetic or neuroscientiﬁc determinism
– that we are ‘born’ or ‘hard-wired’ to behave in a particular • He has a variant in a • She was physically abused
way – can become a self-fulﬁlling prophecy. The prefrontal neurotransmitter receptor gene as a child.
cortex, the ‘thinking brain’, still has plenty of scope to shape that may inﬂuence behaviour.
• She stole a mobile phone to
• He hit a bouncer at a nightclub, give to her boyfriend.
Legally, courts are more lenient if a defendant can prove causing actual bodily harm.
Do any of the factors inﬂuence
‘diminished responsibility’. Sentencing will also depend Do any of the factors inﬂuence whether she is found guilty or
to some extent on an assessment of a defendant’s mental whether he is found guilty or not? not? Should any inﬂuence the
health. So far, there has been little evidence that judges are Should any inﬂuence the punishment if she is found guilty?
willing to consider biological susceptibilities as a justiﬁable punishment if he is found guilty?
defence. As we discover more about the links between brain Should any biological factor ever
and behaviour, it is likely that this will become a more be considered?
Hands off my brain YOUR
Should the contents of the brain be prejudice? And there is considerable interest in using such SAY...
‘private property’? tools to spot when people are lying. There are characteristic On the Big
patterns of brain activity that light up when people are not Picture website
We sometimes go to extreme lengths to prevent people telling the truth (though brain scanners are not 100 per cent you can cast
knowing what we are thinking. The most successful poker your vote and
accurate as lie detectors at the moment).
players have deadpan faces, so other players do not know see how your
what kind of hand they have. Or, in everyday life, we might This may be seen as intrusive. In the USA, the Center for answers
tell the odd little white lie, or not tell someone what we Cognitive Liberty and Ethics argues: “What and how you compare to
really think about them if we want them to help us. think should be private unless you choose to share it.” everyone else’s.
But suppose our real, inner thoughts could be laid bare. Supporters say that brain scanning could have great use –
Functional imaging provides a powerful view of our inner identifying potential paedophiles seeking to work in schools,
thought processes, revealing things that our outer or helping the police solve crimes. On the other hand, even if
expression may be hiding. they were infallible (and they are not) the meaning of scanning
results is open to interpretation. We have instinctive responses
It has revealed that people respond differently to black faces but that does not mean we always act on them.
than they do to white faces – evidence of hidden racial
14 | BIG PICTURE 4