Coren, the psychologist, agreed. He said that one of his heroes, Charles Darwin, "basically claimed if you can prove that an animal dreams, then, in effect, you can prove that's consciousness. Because after all, what is a dream other than a conscious image?"
Wilson's current work goes beyond analyzing dream content and relates to what's going on inside the brain during wakefulness. Using lab-built devices with an array of electrodes, he's found that rats appear to replay memories while doing normal, everyday activities like nibbling on food or sitting quietly. In other words, he said, they're thinking about the past, and possibly contemplating the future.
"The idea that rats may actually be thinking -- just as humans think when they're sitting, appearing not to be doing anything -- suggests the full range of cognitive abilities that we have," he said.
Wilson believes his work extends beyond using animal models to explore human memory and cognition. "It really is using animal models to study animal cognition," he said. "Understanding the differences will give us a better understanding of where we stand in the hierarchy of organisms on the planet."
There's more on animals' sleep and dreams at the National Sleep Foundation.
SOURCES: Matthew Wilson, Sherman Fairchild Professor in Neurobiology, departments of brain and cognitive sciences and biology, Picower Institute of Learning and Memory, Massachusetts Institute of Technology, Cambridge; Stanley Coren, psychologist, author of books on animal behavior
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