Books: The mechanics of nightmares.

The title of Patrick McNamara's Nightmares: The Science and Solution of Those Frightening Visions during Sleep is a bit of a foolish brag. There's plenty of science in these pages, but it all adds up to is one big unsolved mystery. Collecting the latest neurobiological research, McNamara finds it easy to debunk many previous theories and lay assumptions about nightmares (for example, he dismisses the entire body of Freudian dream analysis in a single short paragraph), but he finds it considerably difficult to construct a convincing theory out of what remains. McNamara's solution: Nightmares are an adaptive trait meant to strengthen the sense of self in the young and increase the stature of nightmare sufferers in society through the act of retelling the nightmare in a compelling way. If that hypothesis rubs you the wrong way, rest assured that going into the details of the hypothesis won't resolve any issues you have with it. I have a hard time defending it because it looks half-assed to me. Much of the defense for the adaptive nature of it comes from the sort "just so" stories that make evo-devo the must suspect thing to evolve out of evolutionary theory since social Darwinism. Perhaps somebody with a deeper background in the materials would disagree.

Despite the troublesome central idea, the real value of this tome for the lay reader like myself is the wealth of curious details it collects about the creation, source, and content of nightmares. Although the cover suggests a popular investigation, the book is not written for the casual reader and getting through some of the jargon and citations can make one feel a bit like a sandpiper. Still, there's some fascinating stuff here.

So, instead of doing a typical review, I thought what would be most interesting is to simply cull a handful of details from the book and share 'em with you, my ever-lovin' Screamers and Screamettes.

Here, in no particular order, are some of the choice bits of data from McNamara's Nightmares:

1. Rates for nightmares are somewhat predictable. In children ages 3 to 6, nearly 50% of their dreams are nightmares. This number drops to 20% between the ages of 6 and 12. After age 12, the rate of nightmares drops to just 8%. A small segment of the population suffers frequent nightmares, defined as one nightmare or more a week. Women are disproportionately represented in the population of frequent nightmare suffers. In fact, women generally suffer more nightmares than men. Nobody knows why.

2. The content of nightmares shows some interesting correlations across age. Almost all nightmares, at any age, feature pursuit of conflict with threatening strangers. However, the presence of supernatural threats or monsters concentrates in the certain age groups. The lowest age group mentioned above (3 through 6) dreams about monsters and anthropomorphic animals nearly all the time. Then, inexplicably, monsters and supernatural figures feature in fewer and fewer dreams. Kids ages 6 to 12 dream less about monsters and more about threatening human strangers. Finally, and just as mysteriously, monsters and supernatural characters return to plague adults again. This reflects general trends and individuals and individual nightmares might not follow the rules. But, overall, there seems to be a pattern.

3. In the dreams of children, there seem to be gender-specific variations in levels of perceived "victimization." Young boys start off with high levels of victimization dreams – like some character from a Hostel flick, they imagine that they are under attack and that they can only sit there and endure it. These levels drops consistently over time until they reach the levels found in adult dreams. Young girls, on the other hand, start with relatively low levels of victimization, not all that dissimilar to the levels found in adults (though skewed by the frequency of nightmares which adults don't come close to matching). Then, over time, these levels increase and dreams of victimization become more common. After hitting a peak in late childhood, these levels begin to subside again, lowering to meet adult norms.

4. The issue of whether or not dreams are metaphors for events in the dreamer's life is complicated. All dreams, and specifically nightmares in this case, have access to the dreamer's memories – but only certain types of memories. Except in the really young and in those suffering from post-traumatic stress, nightmares do not have access to your episodic memory. Instead, they're drawing on your semantic and process memories. This has to do with when memories are encoded during sleep. During REM sleep, when normal adult nightmares are most likely to occur, your brain is encoding abstract conceptual meanings and wiring you brain for common, repeated actions. In short, you tend to dream like an amnesiac. You know what a mother is, but you probably don't specifically think of your own mother. You might dream that you're back in college, but it won't really be your specific college campus. Content studies of dreams reveal that, in adult nightmares, less than a quarter of the elements involved (characters, set, etc) are familiar to the dreamer. There are exceptions, of course, but generally your dreaming in abstractions, metaphors without a stable reference.

5. The brain activity of adults suffering nightmares suggests that we experience them not as a slowly building increase in levels of anxiety, but as a series of successive shocks – a bunch of jump scares, to put it in horror film terms. During a nightmare, there spikes in the dreamer's PGO (pontine-geniculo-occipital) waves. These waves are responsible for the "visual" nature of dreams – the phenomenon of believing you "saw" the dream even though you weren't using your eyes. These waves are also connected to your waking orientation response, the automatic response that kicks in when you're startled in waking life. When you get a jump scare in a movie, you're basically feeling awake what you're feeling over and over again when you have a nightmare. This startle response is no joke. Though most healthy individuals have nothing to fear, nightmares can put stress on the cardiovascular system and there's an increased chance of cardiac arrest during a nightmare.

6. Nightmares are, according to the good doctor, "hyperassociative." That is to say that we store our semantic memories (the raw material of nightmares) in networks of shifting associations. Nightmares storm through these links, connecting crap together in overly abundant ways that would be non-functional in waking life. However, there is an artistic parallel. The gothic aesthetic, with its lush and overly-strained metaphors (think of the house in "The Fall of the House of Usher" – it equals the family, Usher himself, a human head, and so on . . .), is possibly the closest intentional and waking humans have gotten to reproducing the construction process of nightmares. The chief distinction is that gothic works build on a chain of meaningful associations while nightmare's are free of that constraint. Could you make a surreal gothic?

Okay, that's enough stuff. We could go on, but then we'd be getting into some pretty esoteric stuff. Like I said, these factoids are pulled out of context and turned into normal-ese for popular consumption. McNamara's actual prose is dense and aimed at the scholar and mental health care professional. As such, unless you're a glutton for punishment when you're on some intellectual hobby-horse, just incorporate these tidbits into your cocktail hour conversation and let it go at that.