Q: Why are our "bad" dreams considered to be "good" for us at times?

A: Once classified as a mental disorder, nightmares are now generally regarded as "any intense negative dream that awakens the dreamer and is vividly recalled on awakening," most often characterized by fear or anger, says sleep and dream researcher Michelle Carr in "New Scientist" magazine. Now, research is showing a possible upside to nightmares. In one of Carr's studies, 14 volunteers (with at least two nightmares a week) "got paid to nap," and though none had a nightmare, all recalled a dream. Actually, "it turns out that people who have a lot of nightmares also have an unusually high number of good dreams," including social dreams that "enhance feelings of closeness in the real world" and enable them to feel what others are feeling — essential in developing relationships.

Furthermore, sleep researcher Ernest Hartmann found that those seeking therapy for nightmares had "a general sensitivity to all emotional experience" that spills over into perceptions and thoughts and seems to give them a creative edge. "For instance, studies show that such people tend to have greater creative aptitude and artistic expression."

Carr sums it up this way: "People who are unfortunate in having a lot of nightmares also have a dreaming life that is at least as creative, positive and vivid as it can be distressing and terrifying. What's more, this imaginative richness is unlikely to be confined to sleep, but also permeates waking thought and daydreams."

Q: What makes gorillas sing for their supper? Or if not that, at least hum hungrily for their food?


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A: Actually, our "gorilla cousins" sing — or hum — AS they supper, characterized by primatologist Dian Fossey as "belch vocalizations," says Steve Mirsky in "Scientific American" magazine. According to a recent study in "PLOS ONE," these sounds are usually made by dominant males of the group and seem to signal contentment (bonobos and chimpanzees also produce feeding vocalizations).

As study co-author Eva Luef explained, these food calls seem to have some social function, since silverback gorillas are often the ones making group decisions. So, the calls may signal to his group mates that he is busy eating at the moment. "In other words," Mirsky says, "humming and singing may be the dominant male's Do Not Disturb sign. And his eventual silence could be gorilla for 'Ladies and almostmen, may I have your attention?'"

Q: At least how long ago did people start hearing the instructions to "Open wide"?

A: According to University of Bologna archaeologist Stefano Benazzi, ancient dentistry goes back 5,000 years earlier than was previously thought, reports Gemma Tarlach in "Discover" magazine. He and colleagues examined the lower molar of a 14,000-year-old skeleton unearthed in northern Italy, containing a large cavity. "Chipping at the top of the molar shows an attempt to remove the cavity, while a microscopic view shows striations on the tooth."

These marks were made with a stone tool in an apparent attempt to remove the infected material, which would have been "quite painful," Benazzi says. Although the effort was only partly successful, at least the patient survived. "Benazzi's analysis included replicating the damage on modern teeth — relax, he used teeth that were already extracted."

Send STRANGE questions to brothers Bill and Rich at sbtcolumn@gmail.com