That post was about sleep researcher Jerry Siegel, who argues that sleep evolved as a state of “adaptive inactivity”. According to this idea, animals sleep because otherwise we’d always be active, and constant activity is a waste of energy. Sleeping for a proportion of the time conserves calories, and also keeps us safe from nocturnal predators etc.

Siegel’s theory in what we might call minimalist. That’s in contrast to other hypotheses which claim that sleep serves some kind of vital restorative biological function, or that it’s important for memory formation, or whatever. It’s a hotly debated topic. (…)

Dreams are simply a result of the “awake-like” forebrain - the “higher” perceptual, cognitive and emotional areas - trying to make sense of the input that it’s receiving as a result of waves of activation arising from the brainstem. A dream is the forebrain’s “best guess” at making a meaningful story out of the assortment of sensations (mostly visual) and concepts activated by these periodic waves. There’s no attempt to disguise the shameful parts; the bizarreness of dreams simply reflects the fact that the input is pretty much random. (…)

While Hobson’s theory is minimalist in that it reduces dreams, at any rate in adulthood, to the status of a by-product, it doesn’t leave them uninteresting. Freudian dream re-interpretation is probably ruled out (”That train represents your penis and that cat was your mother”, etc.), but if dreams are our brains processing random noise, then they still provide an insight into how our brains process information. Dreams are our brains working away on their own, with the real world temporarily removed.

{ Neuroskeptic | Continue reading }

{ Sleep, say US feminists, is the next big issue for women to address — doing less and enjoying more duvet time is the way to go. | Times | Full story }

photo { Abbey Drucker }

Sounds played as you sleep can reinforce memories.

Ken Paller and his colleagues at Northwestern University in Evanston, Illinois asked people to memorise which images and their associated sounds – such as a picture of a cat and a miaow – were associated with a certain area on a computer screen and then to take a nap. They played half the group the sounds in their sleep, and these people were better at remembering the associations than the rest when they woke up.

How can you boost your sleep learning capacity?

As a rule, hit the hay after learning something new – late-night TV and Xbox marathons are a no-no.

That is, of course, unless the skill you hope to learn is a computer game: when Sidarta Ribeiro of the Edmond and Lily Safra International Institute of Neuroscience in Natal, Brazil, got people to play shoot-’em-up video game Doom before bed, those who dreamed about the game during their sleep were better players the next day.

{ NewScientist | Continue reading | Cosmos magazine | Read more }

photo { Malerie Marder }

Anyone who can remember a vivid dream knows that at times the strange nighttime scenes reflect real hopes and anxieties: the young teacher who finds himself naked at the lectern; the new mother in front of an empty crib, frantic in her imagined loss.

But people can read almost anything into the dreams that they remember, and they do exactly that. In a recent study of more than 1,000 people, researchers at Carnegie Mellon University and Harvard found strong biases in the interpretations of dreams.

For instance, the participants tended to attach more significance to a negative dream if it was about someone they disliked, and more to a positive dream if it was about a friend.

In fact, research suggests that only about 20 percent of dreams contain people or places that the dreamer has encountered. Most images appear to be unique to a single dream.

Scientists know this because some people have the ability to watch their own dreams as observers, without waking up. This state of consciousness, called lucid dreaming, is itself something a mystery. But it is a real phenomenon.

{ NY Times | Continue reading }