Sweet Dreams

I was amused when I heard of Matthew Walker’s highly rated book, Why We Sleep. How much can there be to write about a topic like sleep, I smirked. Even for doctors, it seemed a stretch; but writing a book for laymen? But it was highly rated on Amazon, so cometh the discount, I bought the book.

And boy, are the ratings justified! There’s tons of fascinating info on matters to do with sleep. Including the question: what is the purpose of dreaming?

Take the heat produced by a light bulb. It is not the intended purpose, just “an unintended by-product of the operation” of producing light. The technical term for such by-product is “epiphenomenon”. Is dreaming just an epiphenomenon of sleep? The answer is a categorical No.

The first use of dreaming is that it serves as “overnight therapy”. But only if it is “content specific dreaming”, i.e., related to the “emotional themes and sentiments of the waking trauma”. In those cases, dreaming helps the individual move “forward into a new emotional future, and not be enslaved by a traumatic past”. Conversely, those who dreamed but not of the painful experience itself “could not get past the event”.

Another use of dreams is that it helps with creativity. There are many well known examples of solutions popping up while people slept, so much so that one poet St.Paul Boux even used to put up a sign on his bedroom door that read “Do Not Disturb: Poet at Work”! Except that those solutions come up when we dream… just sleeping isn’t enough. This is because during the REM (dream) phase of sleep, the brain draws up new connections among memories and erases others. That redrawing and erasing can sometimes result in new ideas and solutions aka creativity.

By now, you may have a legitimate question: sure, some people are lucid dreamers, most aren’t. So how can you know if it is dreams that help with overnight therapy and creativity or just good old sleep? Ah, via two techniques:

1)      Brainwave patterns are different during the two phases of sleep and so one can know whether/when the sleeper is in dream mode;

2)     Scientists showed photos of common objects like books, cars and furniture to people who were awake. MRI scans tracked which areas of the brain lit up corresponding to different objects. Next, the MRI scans continued when the subjects slept. Voila! Scientists reversed the (topic -> brain area) mapping to (brain area -> topic) to guess the content of the dream. It tallied with the dreamer’s tale most of the time! (Note there are limits on the accuracy: one can guess cars in general, but not the model of the car).

Who’d have thought that the expression “sweet dreams” meant so much more than just “not nightmares”?!