#5. Why We Dream [neuroscience]

NE

Red, theory; black, fact

The Conjunction of Jupiter and Venus

We Dream Because We Learn

Operant conditioning is the learning process at the root of all voluntary behaviour. The process was discovered in lab animals such as pigeons by B.F. Skinner in the 1950s and can briefly be stated as "If the ends are achieved, the means will be repeated." (Gandhi said something similar about revolutionary governments.)

Learning in the Produce Isle

Operant conditioning is just trial-and-error, like evolution itself, only faster. Notice how it must begin: with trying moves randomly--behavioral mutations. However, the process is not really random like a DNA mutation.  Clearly, common sense plays a role in getting the self-sticky polyethylene bag open for the first time, but any STEM-educated person will want to know just what this "common sense" is and how you would program it. Ideally, you want the  creativity and genius of pure randomness, AND the assurance of not doing anything crazy or even lethal just because some random-move generator suggested it. You vet those suggestions.

How Dreams Help Learning

That, in a nutshell, is dreaming: vetting random moves against our accumulated better judgment to see if they are safe--stocking the brain with pre-vetted random moves for use the next day when we are stuck. This is why the emotions associated with dreaming are more often unpleasant than pleasant: there are more ways to go wrong than to go right. The vetting is best done in advance (e.g., while we sleep) because there's no time in the heat of the action the next day, and trial-and-error with certified-safe "random" moves is already time-consuming without having to do the vetting on the spot as well.  

A Possible Neurobiological Mechanism

Dreams are loosely associated with brain electrical events called "PGO waves," which begin with a burst of action potentials ("nerve impulses") in a few small brainstem neuron clusters, then spread to the visual thalamus, then to the primary visual cortex. I theorize that each PGO wave creates a new random move that is installed by default in memory in cerebral cortex, and is then tested in the inner theatre of dreaming to see what the consequences would be. In the event of a disaster foreseen, the move would be scrubbed from memory, or better yet, added as a "don't do" to the store of accumulated wisdom. Repeat all night.

If memory is organized like an AI knowledge base, then each random move would actually be a connection from a randomly-selected but known stimulus to a randomly-selected but known response, amounting to adding a novel if-then rule to the knowledge base.

Support For a Requirement for Vetting 

In "Evolution in Four Dimensions" [1st ed.] Jablonka and Lamb make the point that epigenetic, cultural, and symbolic processes can come up with something much better than purely random mutations: variation that has been subjected to a variety of screening processes.

An Observation and an Exegesis

Oddly, my nightmares happen just after a turn of good fortune for me. However, in our evolutionary past, my kind of good fortune may have meant bad fortune for someone else, and that someone else will now be highly motivated to kill me in my sleep. Unless I have a nightmare and thus sleep poorly or with comforting others. The dream that warned the Wise Men not to return to Herod may have been just such a nightmare, which they were wise enough to interpret correctly. The content was probably not an angelic vision, but more like Ezekiel's valley of dry bones vision in reverse.