Explain the following to the audience: The capacity for neural networks (the pathways of connections in the brain) to change over time is called ‘Brain Plasticity’. It is these changes that allow us to store knowledge of the world that is built up through experience and learning. Every time you learn something new you are changing the neural patterns in your brain and when they become stored, they enable us to understand and predict the world.
How does the brain learn to speak? [Key Stages 3 & 4]
How does the brain learn new things?
What sort of events stimulate new neural networks?
As we get older it gets harder to make new connections. Consider language. When we are babies the brain is able to process a whole range of different language sounds. If those language sounds aren’t used in the place where the baby is growing up, the connections in the brain that allow them to hear those sounds will eventually die away. This means that they are no longer able to discriminate between certain sounds that they could before.
Play the following clips to the audience and, after each one, get them to raise their hands if they think the two sounds are the same. Most people should raise their hands.
Explain that in all three cases the sounds were different, a fact that would be obvious to anyone native to that language or to a baby. If we are not exposed to those sounds when we are young, however, we stop being able to hear the difference between them.
Q: What has happened in the brain when we stop being able to hear certain sounds?
A: The connections in the brain that allow it to discriminate that sound from others have died away because they are not being used.
Q: Why is it harder to learn new languages when you get older.
A: Part of the reason that it is harder to learn new languages when you get older is because your brain stops being able to hear the differences between certain sounds. Another reason is that as you get older it becomes increasingly hard to form new connections that aren’t closely related to things you already know.
Habituation: Why do things stop being surprising? [Key Stages 3 & 4]
What sort of learning are very young infants capable of?
Make a loud sudden noise when the audience isn’t expecting it (this could be done with a klaxon or by slamming a book on the desk for instance). Ask them if they jumped. Repeat the sound but this time make them aware that you are about to do it. Ask them if they found it less of a surprise.
Explain that the brain quickly “habituates” or gets used to new things. Initially the load noise alerts your brain to pay special attention because there might be a threat nearby. Once your brain has registered an event though and nothing bad has happened, it will be less and less surprised each time it happens. Its a type of learning that is unconscious. The brain is simply processing and storing an experience without you even realizing it. Even very simple animals with very simple brains can learn through habituation.
Q: How do very young infants learn?
A: Infants show this type of learning. They will often look for a long time at things that they don’t expect but will look at the event for less and less time each time it is repeated. This has allowed scientists to examine what very young infants already expect about the world. Using this method, they have discovered that infants from a few months of age expect solid things to stop when they hit other solid things, expect things to travel in continuous lines rather than popping in and out of existence and expect characters to be nice to those who are kind to them and ignore those who are mean to them.
Classical Conditioning: How does the brain automatically learn new things? [Key Stages 3 & 4]
What would happen if the bang had signalled a threat? Would my brain still stop being interested in it after a while?
Play audioclip of icecream van jingle, which can be downloaded from here: http://www.freesound.org/people/djgriffin/sounds/20795/. Ask the audience what they think of when they hear that noise? Ask if it makes them start to feel hungry for an ice-cream
Just the sound of the jingle makes most people’s mouth water even if they can’t see the ice-cream van. That is because as children we established a strong connection in our mind between that song and ice-cream. This type of learning is called conditioning – every time you experience a stimulus, you associate it with something else.
Q: What would happen if the bang had signalled a threat?
A: If you became conditioned to associate a bang with something bad happening, every time you heard the bang your body would experience fear and anticipation, even if you knew the bad thing wasn’t necessarily going to happen anymore.
Training and Reinforcement: How can we train the brain to learn things? [Key Stages 2-4]
How do you teach an animal to do something that they don’t naturally do?
Play the following video of a dancing dog:
This complicated behaviour has been learning through training – in this case by shaping the dog’s behaviour with rewards. Every time the dog performs a behaviour that the trainer wants him to, he gets a treat. That reinforces his behaviour so that he does it again and again.
Human behaviour can equally be shaped. We learn much more quickly when the patterns are accompanied by some form of reward. It could be food, it could be drink.
If we want to be healthy, we might exercise to stay fit. This is called a positive reinforcement because we are repeating an action to get to our goal of being healthy. To be healthy we might also avoid eating fast food, this would be negative reinforcement – where we avoid an action to reach our goal of being healthy.
Many things can act as reinforcements by the simple power of association in our brain.
Q: Give an example of positive reinforcement.
A: Any response to this will be appropriate if it requires repeatedly doing an activity to reach a specific goal. Examples include exercising to feel healthy, practicing a musical instrument to get good at it, practicing a sport to beat the other team, etc.
Q: What is happening in the brain when training occurs?
A: When training occurs the neural networks in the brain that code for that activity are strengthened through repeated use. In the long run, this makes that information or response faster and easier.