Part 2 is about how memory is affected by developmental disorders such as autism, Down’s syndrome, and especially savant syndrome, and how the abilities of people with these disorders could be linked to savantism.

People with autism spectrum conditions can often have memory and expertise that is described as “very deep but very narrow”. In other words, they concentrate obsessively on one small area and learn everything they can about it, even if that area is not needed or used. (For example, I once read about an autistic boy who loved to memorise camera statistics and model numbers, but had no interest in using a camera).

One theory of how autism works is an extension of this idea- it is called Weak Central Coherence theory, and basically says that people with autism automatically see things in terms of their smallest parts, “not seeing the forest for the trees.” This means they are very good at identifying and remembering small details, such as changes in their environment, and can actually out-perform people without autism in tasks involving hidden details.This could explain why they are often good at more scientific and reducible subjects that can be broken down into small parts.

However, seeing the small details means they lack coherence, or the ability to put all of the small details and fragments about the world together. This could explain why people with autism often rely mainly on rote memory, but not on associative memory or context e.g. being able to recall the entire contents of a book, but not being able to understand what it means.

Down’s syndrome has a surprisingly small effect on memory compared to the other conditions; the main difference appears to be that people with Down’s syndrome have a weak memory for words so have poor vocabulary and reading skills, and have poor working memory, so can’t organise series of actions or multitask. However, they have almost-normal visual-spatial memory, so can learn by pictures, and the reason for this difference is still unknown.

Now for Savant Syndrome, which is one of the most interesting things I’ve read about for a while (as an aside, this concept was actually first written about by the guy who discovered Down’s syndrome, I love it when things like that happen). People with this (who were originally known as “idiot savants” meaning “knowledgeable idiots”), have developmental disabilities or learning difficulties, but at the same time have special skills that can outclass either typical people (known as talented savants), or experts in their field (known as prodigious savants).

The majority of savants have skills in music, art, or certain types of calculations, even if they often cannot perform normal mathematics, or even read and write in many cases. However, there are a few unusual cases of savants who can actually explain what goes on in their thinking, such as Temple Grandin, who can help us understanding how savantism works.

The thing that connects all savants, whatever their level of skill or disability, is memory, as all of them have an amazing memory for their skill, and anything related to that skill. This has led to a lot of research into how their minds work, as no-one can yet explain why savant syndrome exists. One belief about savantism is that the hypersensitivity often seen in savant and autistic people (10% of autistic people have some form of savant skill) means they perceive the world more intensely than a normal person, so absorb details and connections that others don’t notice.

Another theory is that skills such as theirs are innate, but in a normally-inaccessible/unused part of the brain, and their brain damage allows them to access this area. So theoretically, we could all be latent savants. Experiments have actually supported this; the experiments aimed magnetic pulses directed at their people’s left hemisphere (the area that contains more parts of the brain that help with speech, writing, exact maths organisation etc) so that their right hemisphere (the area which contains more parts that deal with abstract thought, estimation, sounds and colours) was more activ. For a short time after the magnetic pulses, the people improved at the kind of tasks savants are often good at.

While this sounds more like science-fiction than psychology, and the knowledge of how and why that worked still isn’t clear, studies like this are still useful because they show how even when we think we’ve made more sense of how the brain works, it just gets even more intricate,wonderful, and confusing.