Why we dream in metaphor

I have a friend who is starting a new job soon. I just had a dream where I was concerned about whether or not he would like this new morning radio show we were listening to. When I woke up, I knew one was a metaphor for the other, but then I thought, why? Why do we dream in metaphor? Why do we always dream in metaphor, why can’t we just dream about the underlying thing?

Our brains are predisposed to think in terms of metaphor. Why? Because metaphor is closely related to analogy, and analogy is necessary for classification. Metaphor it is a way of dealing with one thing by referring to its analogue, and usually pointing out how responses to that analogue are also appropriate to the original thing. As for classification, if you can find an analogy for some new unclassified thing, then you immediately know the new thing has the same classification as its analogue.

Our brains are hard-wired for classification. It is necessary so we can use limited memory space to store the learned responses for a variety of situations. Here’s how it works: Let’s say you have a hundred different situations, each of which requires you to learn a response composed of nine steps, and the steps must be executed in the correct sequence. That’s ten pieces of information for each situation. To deal with all one hundred situations, that’s 1,000 pieces of information to learn.

Now let’s say that those same hundred situations can be classified into five general classes. Now you only have to learn 10 pieces of information for 5 classes, plus one piece of information for each situation, namely what class it belongs to. Now to deal with all one hundred situations you only need to learn 150 pieces of information. That’s an 85% reduction. If you further assume that each situation has two exceptions from the general class that also must be learned, that’s still only 350 pieces of information, a 65% reduction.

This is how we deal with a huge variety of things from all areas of our life on a regular basis. Classification is the “compression algorithm” of learning. Analogy and metaphor are integral subroutines of that algorithm, without which classification would not work. Dreaming is a poorly understood, but important part of the learning process. This is why we tend to generalize. This is why we alphabetize our DVD collections. And this is why we dream in metaphor.