In 1918, Igor Stravinsky was composing ‘L’Histoire du Soldat’. One night he dreamt that a young gypsy woman appeared at the side of a road with a child on her lap. The woman was playing the violin to entertain the child, who applauded wildly. The next day, Stravinsky could remember the dream and incorporated the gypsy music into the ‘Petit Concert’ piece in the second part of the performance.
Science too has had its fair share of dream-induced revelation: in 1865 Friedrich Kekulé famously arrived at the hexagonal structure of benzene through a dream in which a circle of snakes each bit the tail of the animal in front.
Ten years earlier, Robert Schumann had a dream in which angels dictated music to him. When he awoke, he wrote the music down and used it as a basis of a longer piece published after his death.
More dramatically, Giuseppe Tartini dreamt that he had made a pact with the devil, who, handed Tartini’s violin, proved that he did indeed have all the best tunes. “Great was my astonishment,” said Tartini, “when I heard him play a sonata of such exquisite beauty as surpassed the boldest flight of my imagination.” When he awoke, Tartini tried to recall the piece, with partial success. “The sonata I then composed [the ‘Devil’s Trill’ sonata], although the best I ever wrote, was far below the one I heard in my dreams.”
Beyond these and other anecdotal reports there has been little scientific study of the role of dreams in music. A rare example was a recent study by Uga and colleagues in Italy, who compared the dreams experienced by 35 musicians and 30 non-musicians over a period of 30 days. The musicians dreamt of music nearly twice as much as the non-musicians, and the frequency of musical dreams was linked not to how much they played but the age at which they started playing.
Nearly half the music dreamt was novel, suggesting that new works can be generated in dreams.
Kroth et al. in California asked a different question – is dreaming linked to musical preferences? Their study of 68 graduate students found a range of significant associations. For example, students keen on heavy metal were more likely to dream that they were dreaming, that they had fallen unconscious or asleep, and to experience dreams of ‘recurring pleasantness’. Fans of rap/hip hop were more likely to have sexual dreams. Jazz was also associated with recurring pleasantness, while devotees of classical musical had more dreams of flying and ‘discontentedness’.
Watch or read an interview with Troi, who was born deaf and is the head organiser of Deaf Rave, a music party for deaf people
Running time 3 mins 13 secs
What do you do?
I’m a DJ and events organiser who was born deaf. I founded Deaf Rave.
How did you first get into music?
When I was about ten I got my first Walkman. I’d put the headphones not over my ears, but over my hearing aids. People would look at me strangely, but that’s how I listen to music.
I went to my first (hearing) rave when I was 17, and that really got me into the rave scene. I found that deaf people didn’t really understand raves though – it wasn’t in their culture. When I was 20 I was involved with a pirate radio crew and got my first decks. A deaf girl was having a house party and asked me to DJ there. My cousin, a professional DJ, lived round the corner, so I got a wheelbarrow and loaded his speakers in. It was a great party and a turning point for my career. Afterwards, at deaf nights in the pub, people kept asking me when the next party was. I decided to host one for 700 and Deaf Rave was born!
What part does music play in your life?
For the last six years I’ve been putting on parties and raves for deaf people. These events are really important as they give deaf people a chance to get out and socialise. Nearly everyone at the parties knows each other. All people are welcome but I’d say around 95 per cent of people that come are deaf. There are different levels of deafness – some people have hearing aids or cochlear implants, but the majority don’t. Some parts of the parties could seem strange to hearing people, for example performers signing along to songs instead of singing them.
Who or what has been the greatest musical influence on you?
The people I grew up with made a massive impact. Musician-wise, it has to be Public Enemy and Bob Marley.
What’s the point of music?
Music brings people together, and without music there’s no energy. When I’m listening to music at home it makes me move, makes me feel emotion. I can’t imagine life without basslines and beats.
What’s your desert island disc?
‘Fattie Boom Boom’ by Ranking Dread, a Jamaican singer who’s dead now. I play it everywhere I go.
This idea and the accompanying resources are designed to engage young people in discussion about the brain, how it controls behaviour and whether we are always fully responsible for our actions, using podcasts as a stimulus
This is a whole-class activity involving group work, self-directed learning and practical applications. Note: Strictly speaking these aren’t actually podcasts, but downloadable MP3 radio programmes. The difference is you can subscribe to podcasts using RSS newsfeeds, which update themselves automatically. There are some good sources of freely available technical help on podcasting on the web – see How to make a podcast for more information.
Post-16 students will develop essential knowledge and understanding of concepts of biology, and the skills needed to use these in new and changing situations. They will become aware of advances in technology relevant to biology; recognise the value and responsible use of biology in society; and consider ethical issues of responsibility. Students will learn about styles of reporting in the media and how to create podcasts as a way to distribute information.
Are we responsible for our actions? Using specially commissioned podcasts as stimulatory material, students will discover more about the human brain, its structure and function, and its control over human behaviour.
think about and discuss the ethical and social issues of reporting science news and the influence different styles of reporting can have on the public’s perception of a story
develop knowledge, skills and understanding of brain structure and function
develop understanding of how the brain controls behaviour and what happens when the brain changes
develop knowledge and understanding of the law, personal responsibility and citizenship
draw on existing knowledge to show understanding of the ethical, social, economic, environmental and technological implications and applications of biology, specifically neuroscience
contribute to group and exploratory class discussions
research a biomedical topic and use it as a basis for creating a news story
using the resources provided, create a podcast delivering a biomedical news story.
1 hour of homework (to include listening to the podcasts).
(These resources can be adapted to suit any lesson length or teaching style.)
These resources have been specially commissioned to accompany the issue. These resources are linked to where possible and can also be downloaded individually or as a set at the bottom of this page for offline use.
Podcast: two news reports totalling 15 minutes in length.
Students listen to two podcasts featuring news reports of a fictional court case. In the classroom, students discuss the court case, the styles of reporting and the verdict. Students then research another biomedical story related to responsibility and create their own news story and podcast using the knowledge and skills they have developed during the lesson.
Students will have access to two fictional podcast news reports describing the history, verdict and reactions to a controversial court case. The defendant had a brain tumour at the time he attacked and killed a colleague. His defence was based around the claim that the physical changes in his brain caused him to become more aggressive and impulsive, making him less responsible for his actions. The story is covered in two very different reporting styles.
As well as considering the scientific and legal facts of the case, students must also be aware of the different styles of reporting and how that may influence listeners’ points of view.
Though fictional, the podcasts are based on scientific and legal fact. Scientific, legal and journalistic experts were consulted in the creation of both the podcasts.
Podcast 1: Broadsheet version
This is recorded in the style of a typical BBC-style news programme. All the facts in the case are reported and it gives a clear timeline for the story. The programme team have made the most of the fact that they had exclusive access to the defendant’s family and used this to tell his side of the story. The listener is led to the conclusion that there were victims on both sides of the case.
Podcast 2: Tabloid version
This is recorded in the style of the sort of news programme that might be found on a pop music station. In the report different clips are used to cast doubt on the verdict and the leniency of the sentence. The programme expects its audience to be similarly outraged by the sentence.
Our brain controls our behaviour. Throughout history we have discerned the functions of the brain by studying brain injury and lesions, and the resulting effects on patients’ behaviour.
This case is based on a true story, but has been altered slightly to make it more palatable to a younger audience.
Pete is a 35-year-old carpenter who had previously worked on a number of skilled and successful jobs. Until last year he was happily married with two small children, and was considered generous, considerate and very popular with friends and colleagues.
Pete began to behave very differently. He made inappropriate advances towards women, had many arguments with his wife, frequently lost his temper and became much more aggressive. One day he was taunted and highly provoked by another man and killed him.
In prison it is discovered that Pete has developed a tumour in his frontal cortex that appears to cause him to have an extremely short fuse; on occasions he is unable to control his impulses.
The case goes to court and the brain scans and behavioural evidence are weighed up. Was he really responsible for his actions or is his brain tumour ultimately the cause?
The jury find Pete not guilty of murder but guilty of manslaughter by reason of diminished responsibility. However, because he has already served time in prison, the judge gives him a suspended sentence (and appropriate supervision orders etc.) and he walks free from court. This is a high-profile case, which attracts plenty of publicity.
Notes for teachers
Please be aware that students undertaking research for ‘murder’ or ‘diminished responsibility’ are likely quite quickly to find themselves at extremely unsavoury (depraved) and inappropriate websites. We therefore do not advise students lead their own research on this topic, but use the resources and web links we have provided. See our topic guide.
Suggested lesson plan
These resources are flexible and can be adapted by teachers to suit their lesson length and teaching styles.
Homework: 30 minutes
Listening to podcasts and considering prompt questions on the homework sheet.
Exploration of brain science, the law and science reporting using the topic guide provided.
Introduction to lesson: 10 minutes
Group discussion: 15 minutes
Split students up into groups of four.
Students should use the prompt questions from the homework sheet to guide their discussion.
Did the jury come to the right decision?
What do you think the jury discussed?
What medical evidence would you want if you were on the jury?
What other information would you require if you were on the jury?
Should legal tests be based on current scientific understanding?
Was the man responsible for his actions?
How much control did he have over his behaviour?
How much does your brain control your behaviour?
Do you think he now has control over his behaviour?
Will this change?
Which report did you believe and why?
Do you think the public need to see justice, i.e. people serving time in prison?
What do you think scientists want the media to say when reporting science stories?
What do you think reporters view as important when reporting science stories?
Can you think of other examples where someone might not be responsible for their actions?
Summary: 10 minutes
Whole-class review of thoughts and opinions generated during group discussion.
Class suggestions of other examples of questionable responsibility.
Research and write news story: 20 minutes
Students choose another topic where responsibility for actions is in question. For example:
Students decide/are allocated the ‘style’ in which to report. For example:
science magazine (e.g. ‘New Scientist’)
scientific journal (e.g. the ‘Lancet’)
Students then write the script for the news story.
Here’s our handy how-to guide on podcasting, for use in our ‘Are you responsible?’ lesson idea or for an independent research project
Although the student activity ‘podcasts’ in our lesson idea we put together by an experienced radio journalist, the technical skills and equipment you need are easy to pick up.
Most podcasts are put together by people who’ve never done it before and the results can be variable. We thought it might be useful to tell you how we made these programmes and give you some inside tips from the broadcast industry to help you make your podcast more interesting and easy to listen to.
What you need to make a podcast
A recording device
We recorded all our interviews and links between interviews on a portable MP3 recorder. Although we used a professional recorder (costing around £300), there are much cheaper recorders (£50–£100) that will work. Some iPods and mobile phones can also do the job.
MP3 files are ‘compressed’ audio, so the sound has been squeezed to make the file smaller. The more compressed the file, the more sound that is lost. MP3 files come in different forms, depending on the sample rate. This corresponds to the amount of material saved on the file. A lower sampling rate (such as 48kbps) will take up less memory but wil be of lower audio quality. We recorded our interviews at 320kbps – which means 320,000 ‘bits’ per second. Each ‘bit’ is a single piece of digital information. For most recording, somewhere around 128kbps will probably be fine.
You could record straight onto a laptop or PC but this reduces your options for where you can record.
Most recorders set the recording level automatically; more advanced ones allow you to set the recording level manually. In most instances, the automatic level is fine; it’s only when there’s very loud background noise that you’ll experience any problems, but these can be overcome by using the microphone (see recording tips below).
This can make or break a podcast – if your microphone is of poor quality, the sound quality will also be poor. It is worth investing £50 in a handheld microphone. Get a microphone that can cope with speech and music and that you can hold a reasonable distance from your mouth.
You need headphones to listen to what you’re recording. Reasonably cheap ones should suffice. When you edit, you might find it easier to listen back through loudspeakers.
Computer with editing equipment and software
Most professionals edit their audio on PCs. With MP3 recorders you can transfer your audio to computer via a USB lead.
There is plenty of audio-editing software available. Schools might want to consider purchasing professional software that can be used for all sorts of other applications (recording and editing drama, music, discussions, etc.). We used Adobe Audition.
Many podcasters use freely available ‘open source’ editing software, such as Audacity.
Most editing software is intuitive and works in the same way as cutting and pasting text, so is straightforward to learn. Editing can also be great fun.
What we did
We decided how we were going to cover the topic and drew up a list of possible interviewees and locations. Because this was a fictional scenario, we also scripted certain sections. While it is always important to know your story in advance, normally it’s better to write a script once you’ve done the interviews. We recorded all our interviews on location. For example, the interview with Chris Frith was recorded in the control room of the MRI scanner. This gave each interview a sense of place and the reporter something on which to comment. We also recorded lots of additional sounds, including the background noise and the interaction between a researcher and patient.
We listened back to the interviews and made notes on which bits we wanted to use (the sections that were crucial to our story). This avoids wasting time later. With a half-hour interview you might normally expect to keep around four to five minutes, sometimes even less.
Only then did we start to edit the sections of interview. The first stage is to break it down into rough chunks or ‘clips’. Then, after a rough edit, go through each one to remove any repetition or long ‘errs’/’umms’. The script was written as we went along, making sure that the links between sections of interview made sense. Then we finished off the script and recorded the remaining links.
Finally we put it all together. Better editing software allows you to mix audio together, so a sound effect ‘dips’ down while a interview clip starts. You can hear this throughout the podcasts. If you’re using music, this is also the stage where you can add any background music tracks.
Once we’d got our final mix, we saved it as an MP3 file and published it on the website (we could have also burned it onto CD at this point). There is plenty of information on posting podcasts available on the web.
Note – if you’re using commercial music and intend to publish your finished product you will need a licence. Our podcasts are covered by a licence held by the Wellcome Trust. Some tracks are freely available to use but it’s worth checking first. Be warned: the licensing process is complex and best avoided if possible.
All these come with practice but as we found, almost every stage of the process is fun.
Decide whom you are planning to broadcast to, and the style you’re going to use. Also, choose a length and try to stick to it; podcasts can be as short as three minutes – the same length as a music track.
Don’t be too ambitious – start with a simple podcast that won’t take up more time than you have.
Think of interesting topics and work out how to do them in an interesting way.
Consider recording on location. Unless you’ve got a soundproofed room, locations will also make your programmes sound more professional.
Use a decent microphone and hold it firmly so you don’t get bumps and clanks. Experiment so you learn how far away you need to hold the microphone from the subject for different situations.
In a very noisy environment, hold the microphone very close to the mouth – this should cut out the background noise.
Record each interview as a separate file (or track) – it’ll make sorting it out later much easier.
If you’re interviewing people, make sure that you are familiar with the recording equipment first so it is easier for you to give the impression you know what you’re doing.
Check you’ve recorded what you think you have. It’s always wise to play bits of the interview back before you leave.
Interviewing and presenting tips
Ask obvious questions – What are you doing? How are you doing it? Why are you doing it?
Listen to what your interviewee is saying and react accordingly. Although it’s sometimes useful to have a list of questions, try not to stick to them too rigidly.
Try to be yourself and remember to speak clearly.
Be careful of libelling people – a podcast is covered by the same laws as everything else. Making unfounded comments about a company or individual can land you in a lot of trouble.
Before you do anything, make sure you back up your interview files. Also make sure you keep saving your files as you go along.
Edit the interviews and clips you want to use first before you attempt to edit the whole programme.
Don’t over-edit – cutting out too many pauses will make it sound unnatural.
There is plenty of help available on the web for making podcasts. Computer staff in your school should be able to help you with the final stage of posting your podcast.
This idea and the accompanying resources are designed to engage young people in discussion about the brain, how it controls behaviour and whether we are always fully responsible for our actions, using podcasts as a stimulus
If our grasp of ‘us and them’ goes wrong, we can have considerable problems in life
Most of us take for granted that we can tell the difference between an action we have generated ourselves and one forced on us by another. And most of our social interactions with other people are not consciously thought about. But if our brains are not adept at these activities, life can be very challenging.
People with schizophrenia, for example, show several distorted ways of thinking during psychotic episodes. A common symptom is to believe that one’s actions are being controlled by external forces. In brain scans, this is apparent in activity patterns characteristic of externally applied (rather than internally generated) movements. (An odd consequence of this is that, during a psychotic episode, people with schizophrenia can tickle themselves: they do not perceive the hand doing the tickling as their own.)
Similarly, people with schizophrenia will sometimes hear 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 ignored by most is interpreted as evidence of a deep interest and desire to cause harm.
It is possible that impaired pick-up of social cues also underpins other forms of behaviour disorder. People with antisocial personality disorder (psychopathy) seem less able to identify fearful expressions, so will be less able to tell that their behaviour is having a negative impact on people. Some symptoms of autism, too, seem to be linked to defective recognition of social cues (see ‘Mind the gap’).
Pen and ink drawing with oil entitled ‘Watching Me’, showing two sides of personality.
Our brains are staggeringly clever things. They can take in incredible amounts of information, filter out what is not needed, store away information for future reference, recall past experiences, and control what the rest of the body does. What’s more, they do all these things simultaneously, every waking second of the day. How does the brain do this?
We are just beginning to work out how the brain manages these incredible feats, and how it is that single cells – mainly neurons – acting together can do so many wonderful things.
The brain operates by division of labour: different areas are specialised for different functions. However, these are not independent republics – connections between them are equally important.
Many insights have come from people whose brain injuries have altered their behaviour. The classic case is that of railway worker Phineas Gage. In 1848 an explosion blew a metal rod through his skull, removing a large chunk of his forebrain. Gage survived but his personality changed dramatically. Formerly a reliable worker, after the accident he became a drunken drifter, aggressive and impulsive, his ability to control his behaviour lost with his prefrontal cortex. See our case study on Phineas Gage for more information.
Vision is our most crucial sense. We rely on it for survival, but just how reliable is it?
It is tempting to think of our eyes as mini-cameras constantly filming the outside world. In fact, vision is nothing like that. The seamless view of the world is an illusion created by the brain after it has dismantled the input it receives from the eyes.
For a start, we do not look at a scene in a steady way. Instead, our eyes constantly flicker back and forth (involuntary movements known as saccades), scanning scenes in detail. From this constantly shifting input, the brain builds up a coherent mental picture corresponding to a scene. Try watching someone reading to see these small movements for yourself. Did they think their eyes were moving?
We now know that neurons in our brain specialise in recognising particular aspects of a scene, such as edges or dots or motion. Each neuron has a ‘receptive field’, an area around it that is sensitive to its favoured stimulus (like a detector attached to a security light, which can detect movement within a particular area of ground).
Then, in a computational task of staggering complexity, the brain integrates all these signals to create a visual impression of the outside world.
Another key difference between the visual system and a camera is the phenomenon of attention. There is so much going on in the world that the brain has to filter out unnecessary inputs. One way it does this is by focusing on (or ‘attending’) to a small area at any one time.
We are not very aware of this, partly because our peripheral vision is sensitive to movement, so if something noteworthy happens there we are quick to notice. But it means we take in much less of a scene than we might imagine.
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.
This filling in can be useful. The visual system is often trying to extract patterns. So when it finds one but with a bit missing, it fills in the missing space, so we get a complete coherent picture. But it sometimes leaps to the wrong conclusion. Can we believe our eyes? Not always.
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 to us now but also on what has happened to us in the past. We learn and we can make memories.
Nearly all animals can learn. A simple form of learning is association – some kind of sensory stimulus is ‘remembered’ and an animal’s behaviour changes the next time it encounters that stimulus. The classic example is provided by Pavlov’s dogs, which were given food every time a bell rang. Eventually, they began to salivate in response to the bell on its own.
Human memory is more complex – in fact, we have several different types of memory, involving many parts of the brain.
But what exactly does a ‘memory’ look like in the brain? Again, it is difficult to liken it to anything everyday such as a photograph in an album.
Memories are hard to pin down, as they involve a constellation of neurons connecting together in different patterns. Putting away a memory of Christmas Day is achieved by millions of neural brain patterns firing: some for the taste of Brussels sprouts, others for a favourite carol. The pattern remains after the stimuli disappear, and a memory is born.
In terms of mechanisms, memory making is thought to depend on neurons strengthening their connections to one another – ‘remembering’ that they have been in touch before.
Hippocampal neurons labelled with an antibody against the GluR1 subtype of glutamate receptors. The hippocampus is important in humans in the processes of learning, memory and navigation. GluR1 is a type of receptor common in the brain and nervous system that mediates fast synaptic transmission of signals.
There are some things we wish we could remember better (eg exam answers) and embarrassing moments we would prefer to forget. But once a memory is lodged in our heads, how reliable is it?
How we behave is influenced by things around us but also by things we have experienced in the past. Being able to learn and store information is an invaluable survival aid. So it might be assumed that our memories are faithful records of the past. But there is plenty of evidence that this is not always the case.
Many experiments have shown that our recall is easily biased in a whole host of ways. For example, mood influences memory making – things in tune with our current mood are remembered better. Things we see will tend to be remembered better than things we hear, unusual items in a list are easier to recall, and items at the beginning and end of lists are more likely to be remembered.
We also have a number of ‘cognitive biases’ that affect our recollection. We have a tendency to remember things as better than they seemed at the time (the ‘rosy retrospection’ bias), and when we have chosen one option we tend to associate more positive things with it.
We all show such biases to some degree, but for some people they can turn into a serious problem. People with psychological disorders, such as depression or social phobia, for example, tend to focus abnormally strongly on negative emotional stimuli – an effect also seen in their memory retrieval. Someone with depression will tend to recall the bad times in a relationship rather than the good, or the negative aspects of an event rather than the positive.
With post-traumatic stress disorder (PTSD), ‘flashback’ memories of the trauma are triggered very easily and intrude on normal life. People regularly relive the distressing events from their past. Cognitive behavioural therapy can be used to treat PTSD (and other psychological disorders). There is also interest in using the drug propanolol, which blocks the action of the neurotransmitternoradrenaline and specifically interferes with traumatic memories.
Similarly, there has been interest in using midazolam to block memory making. One small study used it to block memory formation in children undergoing surgery. It has been suggested that midazolam interferes with explicit (conscious) memory making but not implicit (subconscious) remembering; although generally true, this may be an oversimplification.
Another possible use might be with soldiers, who are exposed to the horrors of war and suffer a high incidence of PTSD (though some query the ethics of this application).
One of the most controversial areas is that of ‘latent’ or suppressed memories. This has come to the fore with stories of hidden memories of childhood sexual abuse being ‘rediscovered’. This is a sensitive area, but it is clear that the memory can easily be manipulated and ‘false memories’ implanted. In one recent study, US researchers convinced a significant proportion of students that they had had a bad experience with ice cream; this was sufficiently convincing that the students were put off eating it.
The effect starts young too. Studies of preschool-age children exposed to a rumour of a particular event, rather than the event itself, showed that many children later reported that they had experienced the event.
Implanted memories may also underlie another curious phenomenon: alien abduction. It is clear that a large proportion of people who claim to have experienced alien abduction genuinely believe it. It is entirely possible that they believe it because it is an embedded memory and every bit as ‘real’ to them as any other memory they hold.
This raises the difficult question of whether we should always ‘believe’ our memories. While we need to rely heavily on their faithfulness, it is worth bearing in mind that they may be deceiving us – just as optical illusions deceive our visual perception. Indeed, being uncritical of memories may be problematic. There is some evidence in schizophrenia, for example, that auditory hallucinations – ‘hearing voices’ – may be irrelevant aural memories surfacing into consciousness. People with schizophrenia may be less able to see these as ‘unreal’ and disregard them.
Although there is much still to be learned about the mechanisms of memory encoding and retrieval, it is clear that memory is in no sense a digital recording stored away for future replay. The implications of this for the legal system, for example on the reliability of eye-witness testimony, are likely to be significant.
We are emotional creatures. The brain is not just a logic machine, but also handles emotions – some of the most powerful drivers of human behaviour
Emotion is important to how we experience life. Love, fear, anger, disgust – these are central to human experience. These raw emotions, in different combinations, add spice to our existence, define many of our goals and influence our decisions.
In their crudest form emotions help survival. Fear and disgust drive us away from possible sources of harm, such as predators or rotten food; love helps us reproduce. They have a profound impact on us, affecting almost all aspects of our behaviour and thinking.
One impact is on attention (see ‘The mind’s eye’). We detect emotional stimuli – faces with positive or negative expressions, or spiders and snakes – much more quickly than neutral ones.
Oddly, though, functional imaging (see ‘Ways of seeing’) has shown that the brain also reacts to emotional stimuli before the nature of the stimuli has been explicitly recognised, or even without any conscious recollection that we’ve seen something scary (for instance).
The key brain region here is the amygdala, which receives visual input independent of the main vision processing areas of the brain. If it detects frightening stimuli, it sends messages to other parts of the brain, triggering a series of responses – making us ‘frightened’.
Memories are made of this
As well as preferentially focusing on emotional stimuli, we also remember them better. We tend to remember not the mundane but the events that are emotionally charged – the good or the bad. Again, memory enhancement seems to depend on activity in the amygdala.
Sometimes, though, people do not want to be reminded of emotionally charged experiences. People with post-traumatic stress disorder (PTSD) suffer from unwanted flashbacks and intrusive memories of their trauma. Interestingly, creation of traumatic memories depends on a particular neurotransmitter (noradrenaline), and a drug that blocks its action – propanolol, more usually used to slow the heart – can prevent traumatic memories being laid down. There is interest in using this as a drug to treat, or even prevent, PTSD.
Feelings, nothing more than feelings
Neuroscientists see emotions as well-described and consistent brain responses. They translate into subjective experiences we know as feelings. These derive in part from the physiological changes created by the emotional stimuli, which are registered by sensors of the body’s internal state (internal organs, energy levels, etc).
It is likely that the brain systems handling emotions are not the same as those responsible for feelings. For example, some people with amygdala damage do not show emotional responses but still experience feelings.
Another distinction is that feelings seem to have more influence over long-term behaviour and decision making. So our choices depend in part on our past feeling states.
Emotion and reason are often thought of as enemies – a battle between cold, hard logic and irrational, emotional decision making.
In fact, though, emotional responses may enhance our decision-making ability, for example by helping us to make value judgements about people based on their facial expressions or because of an awareness of our current bodily state.
What governs mood?
Our mood, or predominant emotion, is governed by several neurotransmitters produced in our bodies.
Serotonin enhances mood by reducing depression and anxiety. Antidepressants that increase serotonin levels are now widely used to treat depression. Interestingly, low serotonin levels have been found in suicide victims.
Dopamine, nicknamed ‘the pleasure chemical’, promotes a feeling of bliss. This explains the attraction of alcohol, nicotine and drugs such as cocaine, all of which increase dopamine levels. Some research has found a correlation between increased levels of dopamine and schizophrenia (though other factors are also involved).
Playing sports makes us feel better due to the release of noradrenaline, another feel-good chemical. Pleasure is also increased by endorphins, the body’s natural painkillers, which are also released during exercise.
Other chemicals, such as GABA and histamine, may also influence mood. Our final mood is governed by complex interplay between all these chemicals, with each chemical’s level being modified by factors such as heredity, environment, lifestyle – and even diet.
Research has tended to look at the dark side of life – anxiety, depression and so on. The flipside, happiness or contentment, has been neglected, but ‘positive psychology’ is now receiving more attention