Why do we dream?

Recent mention in New Scientist filled in some more detail on dreams.

Our broad understanding is that dreams are a way of processing the day's events, cataloguing and storing them away.  And that dreaming happens only in the REM (Rapid Eye Movement) phase of sleep.  This accounts for about a fifth to a quarter of sleep time, in about four bursts.  I remember hearing of an experiment that found a stimulus of a ringing bell (that woke someone up) was incorporated into the final part of a dream that was quite lengthy.  The report suggested this meant dreams were actually quite rapid.

In fact, dreams have been found in both REM and non-REM states - but they each seem to have different content and purpose.

A key idea reported by New Scientist is that REM dreams are a way of dealing with experiences: good or bad, the experiences are relived (and filed away) without the accompanying stress, thus dampening down the emotional impact of those experiences, helping us to achieve an equilibrium over time.  REM dreams are more narrational, emotional, and aggressive.  The suggestion is that the dreams with aggression help us cope with real aggression.  Many such dreams involve unknown males in aggressive interaction with the dreamer.  REM dreams also improve our memory and problem-solving ability - presumably through background storage, retrieval and calculation functions.

Non-REM dreams, by contrast, often involve friendly interactions, suggesting they foster co-operative behaviour.

New Scientist report, with references, here.

Synaesthesia unmasked

There's a science fiction story I remember (H L Gold's The Man With English) with a particularly memorable last line.
A man ended up in hospital as a result of an accident. He started complaining that the bed was too hard, but when they made it softer, it felt harder to him. Hotter felt colder, and so on. The doctors felt they had to operate on him to fix this peculiar condition where his senses were topsy turvy. This they duly did; when the man awoke afterwards, he sniffed around and demanded: “what smells purple?”

A May edition of New Scientist revealed the mechanics behind the very peculiar condition synaesthesia, whereby a small number of people experience senses spilling over into other realms. Some very common examples are people for whom words all have particular colours; or maybe each day of the week comes with a consistent colour, or particular words evoke particular tastes when seen.



Daniel Tammet, mentioned here a few times in the past, presents a particularly interesting case. He has Asperger's, aka high functioning autism. His memory is incredible, and he also experiences words as specific colours. Much more meaningful, however, is his relationship with numbers, which he loves. For him, each digit has a specific shape and evokes a particular feeling – indeed, he experiences a unique shape for every number up to 10,000. This greatly helps his ability with numbers: he has recited from memory pi to over 20,000 digit, by following the shaped landscape in his mind. He also sees the multiplication product of two numbers simply by the shape of the space between the two.

The New Scientist article says synaesthesia is involuntary, runs in families, and is thought to be due to incomplete pruning of neural pathways during the brain's development so that connections remain that are not there for most of us. For example, in a colour synaesthete's brain, the area processing colour does actually show activity when stimulated by the linked concept.

Why would one letter or word evoke a specific colour? The answer appears to be sometimes individualistic (based on the person's early experiences that forge consistent responses), but there are certainly some common crosswirings that have very simple explanations.
First words tend to evoke colour responses on the basis of the first letter – Tammet has himself commented on this. Also, the more common letters are typically associated with common colours, and less frequent letters with rarer colours. Next, colours are often associated with the first letter of the word – for example, B is frequently seen as blue or brown. Y is often yellow for English-speaking synaesthetes, but for Germans, it's G they often associate with yellow - which is gelb in German.

There is a lot more to it, but the above substantially demystifies a very odd condition. It doesn't speak directly to Tammet's memory ability, for example, but it does give a hint that links these related phenomena to brain abnormalities.

In the majority of people, congenital brain abnormalities can be overwhelmingly burdensome but for some, they open up new pathways.

13-Sept update:What does this mean in the context of the broad span of evolution? Possibly not much, because
a) The indications so far are that these neurological wirings happen at the level of the b0dy's physiology, not the gene, and so don’t inherit;
b) Evolutionary supremacy is the story of small genetic mutations dominating in the general population, on the basis of superior survival in a given environment. And the greatest implications of rewiring – superior numerical or memory ability – may not confer special advantage in a technological environment.

But the latter is open for debate.

The fascinating brain and Oliver Sacks

Oliver Sacks is a British-born, US-based neurologist – a specialist in brain physiology.

Most people will know his writings from either the film Awakenings, or the book title The Man Who Mistook His Wife For A Hat. There’s a lot more depth to his work, though, than would be suggested by being associated with either a quirky title or a quirky actor (Robin Williams, who played him in the film). In fact, he’s somewhat taken aback by that strong association with Williams.

His writing is actually very interesting and readable – and he is so darn erudite and philosophical, it would be painful if his writing style was any less lucid.

His books are largely compendia of clinical case studies* – from a thoroughly fascinating discipline. The books are imbued with such meaning that today I was compelled to buy his book An Anthropologist On Mars, despite having a copy at home. (That copy is due back in the library, but the book is of lasting significance, so must be replaced.)

His work encompasses physical disorders of the brain, and the effect of that pathology on the mind, and on behaviour. Who we are, what we perceive, and how we perceive, are strongly influenced by the physical, the chemical makeup of the brain, and this is made most clear where the brain suffers trauma. Through these books, those traumas are depicted as due to either accident, illness (including tumours and epilepsy), or congenital malformations.

Throughout this work, questions are posed as often as answers are posited. Overarching answers seem to be elusive, but there is a theme of working towards a better understanding of how we are what we are. How we are governed by the fact that our minds - our conscious selves – are located in a physical organ.

Although all I have read so far is worthwhile, I favour Anthropologist On Mars, probably because he gives himself space to range more freely on the gamut of ideas raised by each given clinical situation.

One of the subjects of his pondering is the eponymous Anthropologist – Temple Grandin, a professor with high-functioning autism, who said she felt like such a person, in her interactions with other people. Typical of autism, but as with others at the higher end, she has to continuously work out how to interact with people, rather than just do it.

All of this encompasses more than can be expressed in a single post. There’s still more to come on autism, as well as:

• Perception: how do we learn it? Why the story isn’t over when an adult can see for the first time
• Emotion: how you can feel good after brain damage – are you a better person?
• Memory: if recall can be perfect in a mis-functioning brain, why is it less so in a normal situation?

And just how does Daniel Tammet – just through visualisations - calculate and remember like a computer ? Brain damage or genius, he has something we don't.


*Interestingly, I recently conversed with someone who also recommended Sacks’ memoir, Uncle Tungsten: Memories of a Chemical Boyhood. Looks like there are a few erudite people out there.

Tech: The tech personality 2: three mathematicians

I was struck by the profiles of three people who have a mathematical aptitude of one sort or another.

For some people, mathematics takes work. For some, it comes easy. For others, it's an art form.


Australian Terence Tao is the youngest ever winner of the Fields medal, the "Nobel of maths". His mathematical interests are wide-ranging, and he appears particularly well-adjusted.

Russian Grigory Perelman was also awarded a Fields. He declined it because they didn't understand his work - a mite unfair, because you don't need to understand some maths in full to appreciate its truth, beauty and relevance. The Fields was awarded to him anyway. He has apparently solved a very important puzzle - which will probably fetch him the million-dollar millenium prize. He apparently withdrew from mathematics in protest against a perceived lack of ethics in certain people in the upper echelons of maths. Currently unemployed.

Englishman Daniel Tammet has Asperger's Syndrome and, unusually, some insight into his condition. He also has an eidetic memory. He can recite pi to 22,000 places - "as beautiful as the Mona Lisa". He can multiply numbers in his head very easily - as does Tao - but interestingly, he can't do square roots (as some can), and can't do abstractions such as polynomials.

Three very different personalities. All very interesting. I can appreciate them from my love of mathematics, although they're leagues above me.

Here are their Wikipedia entries: Tao , Tammet, and Perelman.
And here's some interesting press about them: Tao, Tammet, and Perelman.

All six articles are worth a read.

World: How to save your brain

A new study in Nature magazine has shown that clever children have thicker brains rather than bigger brains. For less intelligent children, cortical thickness peaks at age 8, at which time it is thicker than smarter children. But then thickness decreases for average kids, and increases in smarter kids up to age 12.

The brain is a network of neurons. Implicit in the study is that the network is getting more complex when the cortex thickens. The number of neurons doesn’t change, but the number of connections between neurons does.

The researcher said the thinning was thought to be due to a “use-it-or-lose-it” strategy, where connections were pruned as the brain streamlined its operations. So exercising the brain stimulates the number of connections.

Children need stimulating, otherwise their brains “dumb down”.

The same is true at the other end. A New Scientist article (“Use it don’t lose it”, 17 December 2005) said exactly the same thing about older people. It described a retired university lecturer who was “intolerably good” at chess. He found he could no longer think eight moves ahead, only five. Tests designed to spot early dimentia didn’t reveal any problem. Yet after he died two years later, his brain was found to be “riddled with plaques and tangles, the hallmark of Alzheimer’s disease”. This is an example of “cognitive reserve”, where people who lead intellectually stimulating lives are more protected from degeneration of the mind. They also recover better from “stroke, head injury, intoxication, and … neurotoxins”. Sounds like common sense, but it’s certainly surprising to hear someone can be riddled with Alzheimer’s and function well.

I guess you’re lucky if you’re the kind of person who enjoys being intellectually stimulated.