If you were only allowed to take one thing from educational neuroscience – one nugget of learning to gift to the children you teach – it would be understanding the concept of brain plasticity. Ok so it’s not a gift like a new Nintendo or a car, but understanding it is a skill that will take them further than a car and last longer than a games console. And I’ve yet to meet a schoolchild that doesn’t understand it, no matter how young.
Learning about brain plasticity could be, quite literally, life changing. Educational research shows that simply understanding the concept of brain plasticity alone is enough to improve students’ academic performance. In classrooms, this holds true even if a teacher changes nothing else about the way they teach.
‘Plastic’ comes from the Greek ‘plastos’, meaning to mould or shape. The fact that our brains are so malleable is what makes us experts at adapting to the world we live in. Despite having less DNA than an onion, humans express extraordinary variation: a child can grow up to be a violin virtuoso, speak eight languages or get full marks in the pub quiz. Some of the genes you’ve passed onto your child will be promoted, others will be repressed – a process governed by the environment you raise them in. Modifications to cognitive skills such as learning and memory happen during early development. We are biologically cultural. And education is a significant acculturing force. We are born to learn.
Learning.
Aristotle is credited with saying, “We are what we repeatedly do. Excellence is not an act but a habit”. ²
Carol Dweck, of the Growth Mindsets movement, argues that we are not born with a fixed level of intelligence, instead we can alter our intelligence through effort and work.
At a cellular level, learning happens when neurons make new connections with each other. Projections, called dendrites, branch off the neurons – and off these, further protrusions called dendritic spines. Some neurons can have up to 30,000 dendritic spines on them.
When we experience something new, the dendrites on our neurons form new dendritic spines to make new connections. Forgetting to turn off your microphone during an online lesson (so everyone hears you yelling that the dog’s just been sick) causes new dendritic spines to form, in order to make new connections with other neurons, so that the next time we are in that situation there is a neural network in place to remind us to TURN OFF THE MIC. We learn not to make the same mistakes.
This rewiring can happen numerous times in a single day – listening to the news or hearing your students’ ideas alters your brain’s wiring before you’ve even had morning coffee. Each time your children learn something new, parts of their brain rapidly form a new neural network to record the information.
Plasticity.
Given the number of neurons in a brain, and the potential connections between them, the capacity for communication is astonishing.
Where spines from one neuron connect with the terminals of another neuron, a synapse is made. The neurons don’t actually touch - they leave a tiny gap, called a synaptic cleft. Communication happens when chemicals, called neurotransmitters, move across this gap. This can happen incredibly quickly – up to 268 miles an hour.
We have a finite number of neurons. If it is not used, a connection will shrink and disappear allowing the resources to be directed to more essential connections. The processes driving connectivity is potentiation. The reverse is depression (not to be confused with the emotional state).
In a nutshell, if a part of the neuron is being used more often, potentiation causes the next neuron along the chain to be more responsive – by releasing more neurotransmitter into the synaptic cleft, or by increasing the number of receptors on the receiving neuron. Potentiation can also trigger a greater response by adapting neurotransmitter receptors, or changing the kind of response produced by the receiving neuron, so that the same amount of neurotransmitter causes a larger response. This kind of plasticity tends to be short-term, lasting only for seconds or minutes. It happens when we are concentrating hard on memorising our family’s food order at the pub to avoid a burger-related tantrum.
Potentiation may also change the structure of the neuron itself, by making it longer or increasing the number of its dendrites. This usually happens for connections that are being used long-term - for months, years or even decades. Like remembering your child’s name. Or still knowing your childhood landline number decades later.
There is a saying in neuroscience: neurons that fire together, wire together. As information is received from the senses, processed and integrated, it leaves a ‘trace’, and the more this trace is used, the more robust the memory will be.
When your baby was around three to four months old, they learned that kicking their legs in the crib made the mobile move. Soon, each time you put them to bed, they kicked their legs. When they were three, getting dressed was painfully slow – head through the big hole, label at the back, buttons at the front, hold onto the cuffs. But now, when they hear the car revving outside the front door, they can get dressed in under a minute. Your teenager can type messages to his friends in what seems like microseconds. Potentiation ensures that these connections that are used often are super-efficient; it’s what makes us expert at things.
Depression is the opposite. By pruning unnecessary connections, communication travels around the brain efficiently. When your child was learning to read, they first memorised phonics. When you read, you no longer identify the phoneme within each word because you are expert.
Forgetting.
But an important part of learning that is often overlooked is forgetting. Dendrites can retract and reduce their number of spines – and if we didn’t forget unnecessary information, life would be harder. Ultimately, the aim of memory is to help us survive. It does this not by remembering every detail, but by remembering the general gist of situations. Too much detail gets in the way – if you were bitten by an Alsatian dog on a beach, and your memory was too specific, you would only be wary of Alsatians on that beach, not of all dogs in parks or the woods. A baby learns to recognise faces not by memorising every human face it sees, but by getting the general gist that faces have two eyes, a nose and mouth. Unless you have the condition, or gift of, hyperthymesia, in which case you know precisely what you ate for lunch on the 15th October 1996.
Brains like to streamline, in order to make as much of life happen in the background, on autopilot, as possible. Year 3 students can read faster now than they could in Year 2, because they no longer need to sound out each letter or phoneme. Their brains have updated their wiring to form efficient circuits for reading.
However, this streamlining can also be a problem – we rely on assumptions, based on our own subjective past experiences, to interpret the world. And not all of these assumptions are correct. As the saying goes, assumption is the mother of all mess ups.
Stress affects brain plasticity.
Under stress, the parts of the brain that detect threat change to become more vigilant and anxious. The structures related to learning and memory can decrease in volume. Learning to avoid a violent member of the family will be banked; learning to spell the word ‘favourite’ will not. Times tables just don’t feature on the brain’s evolutionary list of ‘What to remember to help me stay alive’.
Stress also causes plastic changes in the prefrontal cortex, the front part of the brain sitting behind the eyebrows. The prefrontal cortex is responsible for a whole host of higher-order jobs, such as planning, working-memory, and emotional regulation. It is the part that makes us human. The prefrontal cortex liaises with the amygdala and the hippocampus, the parts that help form long-term memory. Long-term stress reduces prefrontal cortex volume, and ultimately impairs its functioning².
Why understanding plasticity improves grades.
Sanne Dekker and Jolle Jolls, from two different universities in the Netherlands, asked teenagers how they viewed intelligence³. Did they hold an entity theory (you can’t do anything to change it) or incremental theory (you can always change how intelligent you are)? The experimental group of students then completed three modules, learning about the brain processes behind learning and brain development. The control group did not.
Afterwards, the experimental group changed their beliefs about intelligence: on average more students believed that through hard work you could become more intelligent. They were thus more likely to keep on trying in the face of adversity.
Which ties in nicely with Dweck’s growth mindsets: with determination and by learning from failure we get ‘cleverer’. As well as with other heroes and heroines from the world of cognitive psychology such as Angela Duckworth (having the grit to stick at something trumps any natural talent when it comes to success) and Malcolm Gladwell (who similarly found that it takes around 10,000 hours to reach expertise). Which all good teachers and parents know anyway. Still, it’s nice to know that there is a scientific reason why.
NB: In fact, the differences in the DNA of an onion and ourselves are more about the rate of loss of junk DNA than an intelligence indicator, but the onion helped make a nice point.
Dr Rebecca Torrance Jenkins
Head of Science, Kingswood Prep School, UK
¹ In fact it was Will Durant who first wrote this phrase in his small book, The Story of Philosophy, in 1926, when summarising Aristotle’s thoughts on morality in Nicomachean Ethics. The original is less catchy.
² Radley, J., Morilak, D., Viau, V. and Campeau, S., 2015. Chronic stress and brain plasticity: mechanisms underlying adaptive and maladaptive changes and implications for stress-related CNS disorders. Neuroscience & Biobehavioral Reviews, 58, pp.79-91.
³ Dekker, S. and Jolles, J., 2015. Teaching about “brain and learning” in high school biology classes: Effects on teachers’ knowledge and students’ theory of intelligence. Frontiers in psychology, 6, p.1848.