In your native language, your brain recognises – and endows with meaning – any conceivable subset of 50,000+ words within fractions of a second. That is in stark contrast to what you will experience with subsequent languages where initially nothing ever happens in milliseconds. Imagine that, during your first trip to Paris, a friendly local takes you on a two-hour stroll from Notre Dame to the Louvre, then northwards up to the Sacré-Cœur, and, finally, down to Pigalle. If I put you back at Notre Dame a few months later, you would probably find your way to Pigalle alone, recalling places, streets, crossroads, shops, and buildings. It is hard to believe that this wealth of information is approximately equivalent to learning 20 miserable words. Why does it take adults so long to learn languages while young children seem to do so whilst playing, laughing and having a great time? Do we all, shortly after infancy, suffer a subtle form of partial Alzheimer’s disease? Or are adult brains tuned to find their way in urban jungles rather than in word jungles?
Let’s take a glass. Imagine that I put my finger on it and ask you what it is. You would answer ‘glass’, instantly, without hesitating. The word pours out of your mouth as water pours out of a spring. It does so because ‘glass’ is woven into your brain in many different ways: you have a mental image of a glass; you have a memory trace for the spoken word; you have a memory trace for the written word; you know that the word has 5 letters, that it starts with a g and ends with an s; you have a motor recipe for pronouncing the word; and, on demand, you can recall hundreds of memories associated with the word – glasses raised to celebrate births, marriages, and anniversaries, or a glass smashed against a wall. ‘Glass’ is embedded in a dense web of events and things in time and space. Figure 6.1 shows one such web. Any single of your 50,000+ native words is intertwined in multiple locations of your brain, floating in a sea of meanings, facts, and emotions. As soon as you wake up in the morning, all brain words go into stand-by mode, waiting to jump into consciousness as soon as their equivalents – written or spoken words – enter the brain via your eyes or ears. Grown over decades, this vast network of word webs is the most precious asset of your life.
To manage word webs – and other tasks, of course – your brain relies on complex and compact machinery. First, it contains around 100 (1011) billion neurones, which are the main information-processing cells. Second, these neurones are connected to neurones either in the vicinity or far away. In young adults, the long distance fibre tracts total around 176,000 km in length – that is roughly half way to the moon.
Third, each of the 1011 neurones is linked to other neurones by up to 10,000 so-called synapses. These are highly specialised interfaces where information is passed from axons – slim extensions that carry the electric signals generated by the neurones – to dendrites, which are highly branched tree-like structures that receive the signals originated in other neurones
(Figure 6.2).
Figure 6.2. A single neurone, its dendrites and its multiple synapses (orange dots).
The resulting picture is majestic: one billion synaptic connections in a single cubic millimetre of specialised brain tissue, up to 1000 trillion (1015) in a human brain. One thousand TeraSynapses – that is the number of stars in ten thousand Milky Ways.
Yet the most surprising detail is still to come: synapses are not carved in stone. They come and go as their support, so-called dendritic spines, appear and disappear. These spines are tiny protrusions from a neurone’s dendrite. If you teach a mouse to reach out with its forelimb to a single seed, dendritic spines form as rapidly as within one hour. Most of these new spines will regress again, but some are preserved and stabilised during subsequent training. The resulting change in circuitry is most likely the anatomical substrate for long-term memory storage.
The resulting plasticity of the brain can even be observed macroscopically, for example in London, taxi drivers from pre-
GPS times who developed a hypertrophy of the brain region that is involved in spatial orientation, or in violin players who have an enlargement of the left hand representation in the sensorimotor cortex.
The rate of spine erosion is astonishing. Most newly formed spines vanish within days, and only a fraction persists for months. Using 20 percent of all the oxygen you breathe, your brain is constantly sorting out newly received information, enforcing what is important and discarding what is irrelevant.
The extent of the deconstruction going on in your brain was nicely shown by 19th century experiments that measured the time of learning – and subsequent forgetting – of chains of 2,300 nonsense consonant-vowel-consonant syllables such as KOJ, BOK, and YAT. The results were sobering. After 24 hours, 70 percent was gone (Figure 6.3). Happily, you will learn meaningful word pairs rather than nonsense syllables, for example, agua–water, vino–wine, queso–chesse, and should therefore obtain better results after 24 hours. However, at Day 31, you might not perform much better than the memory pioneers more than 100 years ago. Brain physiology isn’t prone to instant word learning.
In word jungles, progress is slow.
In order to protect young spines from erosion, schedule multiple training sessions. You will note that, before getting fixed into lifelong memory, words pass subsequent degrees of knowing. At the weakest stage, you don’t even remember that you have seen a word; however, you would recognise it when presented in a list of words. Later, you would say that you once knew a word, but cannot remember it. At a subsequent stage, a word would be on the tip of your tongue, yet decline to come out. Finally, you remember it, first after seconds and then milliseconds.
Figure 6.3. Forgetting curve. Adapted from Hermann Ebbinghaus, Memory: a contribution to experimental psychology, 1885/1913.
For our immediate purposes, we will define knowing a word as successful recall after one month of non-exposure. Only occasional words will get there after the first encounter. The vast majority –alas! – will have to be subjected to the long process of multiple rehearsals through reading, hearing, or conscious repetitions.
Never forget: baby memory traces are volatile. Imagine your word brain as a castle protected by high walls and ruled by the lord of the castle, who has issued unambiguous instructions to the sentries at the gate: no entry without multiple petitions and repetitions! Memory’s suspicious gatekeepers want convincing evidence that a word deserves residence in lifelong memory. Be prepared to come back as many as 5, 10, or even 20 times, to plead the cause for every single word. Take comfort from the idea that subsequent learning rounds require less time and produce better results, allowing the learning sessions to be spaced out. If you meet a word for the first time on Day 0, repeat it on Day 1, 3, 6, 10, 17, and 31.
Figure 6.4. Learning curve (red), constructed from truncated forgetting curves.
Dark blue: Initial decline in memory performance.
Light blue: Long-term result without further repetition.
Green: Repetition putting the retention rate back to 100 percent.
Figure 6.4 illustrates these ‘spaced repetitions’ and where they will take you. Be prepared that the sum of all the repetitions may total around 4 to 6 minutes per word.
We realise that the word learning is hopelessly inadequate to describe what you are going to do. First, learning does not reflect the subsequent degrees of knowing. Second, learning implicitly suggests forgetting. How many things did we once know and have since forgotten? What is fine for physics and higher mathematics, most of which is irrelevant in ordinary life, is intolerable for languages where you need every bit of information for the rest of your life. I am therefore reluctant to tell you that you learn words when, in fact, I mean that you need to store them in your word brain in a fairly definitive way. You must etch new words and carve and pound and burn and nail them. The alternative for learning should express that a word will stay in your brain for decades: it may corrode and slowly become weaker, but it will nonetheless resist and surrender only to arteriosclerosis. Let’s abandon learning, which is too cushy, and adopt something more physical. Let’s say nailing. The definition of nailing includes the three steps of learning, repeating and controlling.
Contribution by Maitee Rodriguez club memberships white coat
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