I’m appearing tonight on BBC1 at 7.30 p.m. in an episode of “Bang Goes the Theory”, which has devoted tonight’s episode to memory. They wanted me to teach presenter Dallas Campbell the periodic table, so he knew it by heart. I was to have no more than a few hours with him.
The periodic table displays all 118 chemical elements in organised fashion. To learn it, you not only have to learn all the elements- whose names quickly jump from the familiar – tin, chlorine- to mind-benders such as “protactinium” and “ununquadium”. You also have to know the order that they come in, and also the number associated with any given element.
It really is quite a task. Learning such a giant mass of information presents numerous challenges to the memory. The first, and principle difficulty, is the confusability of the elements. To take just the elements beginning with the letter ‘R’, you have Ruthenium and Rhodium and Rhenium and Roentgenium and Rubidium and Radium and Rutherfordium and Radium. Aaaaaargh.
Similar sounding words -whether elements or not- always have a high chance of getting confused. This is especially the case where they do not yet have any distinct meaning of their own in your mind. Did either Dallas or I have any special opinions about the distinction between Rhodium and Rhenium? Did mention of Roentgenium as opposed to Ruthenium cause different reactions within our minds? Hardly at all. This made the learning of just the elements by themselves a real issue: they were poised to overlap and interfere in our minds, and we needed to make sure
The second major difficulty confronting us was to learn the order. The sequence of a set of items can be easy enough when it’s fewer than 20 long. You can tell a story, or just repeat it by rote and get feel for the sound. But when it comes to a list 118 items long, heavier-duty memory techniques are required.
The third great difficult we faced was that we needed to be able to find an element in our memories according to the number. To be able to hear “94” and think immediately of “Plutonium”; to be asked what the 81st element is, and to be able to know immediately that it is Thallium, that it is preceded by Mercury and that it is followed by Lead.
So much for the task. Here’s how Dallas and I managed to complete it in three hours.
First we went, plus BBC film crew to Battersea Zoo. We needed to be in an interesting space, because we were going to use the space as a mental receptacle to contain all of the elements. People intuitively know the sequence of the various components of a familiar space: and we were going to use the ancient “method of Loci” to borrow that spatial structure and lend it to the elements themselves.
At the zoo, we divided up the elements into 12 groups of ten, and learned the order of those twelve spaces. The monkey-enclosure was going to be where we stored the memories for numbers 20-29. The children’s playground was where we would store number 100-109, and betwixt and between the other ten groups of ten elements among turtles and otters and butterflies and picnic areas and so on.
By fixing groups of ten to particular locations, Dallas was able to get an overview of the whole. The sixties, he knew, automatically were to be found among Llamas; the forties among snakes. And so on.
So if I were later to ask him what the 45th element of the periodic table was, he’d know to go directly to the snake house in his imagination.
But how did we then store the elements in that location? Well, for each element, we found an image. The brain loves images, and they can of course easily be imagined in location.
Some of the images were just the expression of an association that Dallas already had with the element. Mercury, he knew, was in thermometers; Radium, he knew, was extremely bad for your health.
For all the others, though, we had to imbue what was often an element neither of us had ever heard of or pronounced, and find an image that would not only help remember the internal structure of the word, but also make it possible to recall it effortlessly in context.
In this way, we learned “Niobium” through the image of a friend of Dallas’ called “Naomi”; we learned “tantalum” through an image of Tantalus reaching for grapes; we found for “Palladium” the image of the London Palladium (Dallas, an actor as much as he is a presenter, had some experience of the place).
In this way, over the course of around three hours, we laid down 118 images across the zoo. And we cycled back and forth over them, making sure to practice recalling them backwards and forwards, making sure Dallas was able to enter this “memory palace” from any angle and head off at any angle.
This is a pretty mentally demanding process, and it’s normally the case that when you lay down this many new memories your head begins to ring. To quantify it, Dallas probably learned, in total, around 500- factoring in all the new words he learned, the new space of Battersea zoo, the connections he was making and the corrections he had to make as he was going along.
Nonetheless, after just a few hours in the Zoo, we headed to the Royal Institution, where a giant periodic table was covered entirely by pieces of paper. It was a cool place to do the test- the same space where Faraday and others revealed their discoveries during the golden age of British scientific discovery a couple hundred years ago, when many of these elements were first discovered (if not yet put into the periodic table, which came later).
So there in the basement of the Royal Institution, I tested Dallas on every single element in the periodic table. “What is number 27?” I asked. “Cobalt” Dallas replied, jumping flawlessly to the right place in the zoo, decoding the image and saying the element outlaid. And number 66? “Dysprosium” 65? “Terbium” 93? “93 is Neptunium” 49? “Indium is 49”. And so on Dallas went, without error, through all 118 elements.
It was pretty good fun, and if you want to catch it in action, check out BBC1 tonight at 7.30 p.m. , where you’ll also be able to catch my old neuroscience prof at Oxford, Kia Nobre, talking through the brain processes involved in memory.