I'm Not Listening Why does a snorer never hear him or herself? The noise can be truly awesome, as any victim can attest, and I'm at a loss as to how anyone can sleep through the echoing thunder coming from the pillow next to our own. Why are we the only ones to hear it? Why can't the snorers? Dr. Meir Kryger, Professor of Medicine at the University of Manitoba and Director of the Sleep Disorders Centre at the St. Boniface Hospital Research Centre in Winnipeg: This listener is going through something that many people go through, and it can certainly seem mystifying that a snorer can sleep through the tremendous racket they make. The explanation lies, of course, in our brains. Our brain basically ignores information that it doesn't consider important. The snorer's brain just decides that the noise from its own snoring is not going to wake it up. We used to think that the sleeping brain was basically in neutral, idling and not doing much. All sorts of experiments have proved that this isn't the case, that the brain is extremely active during sleep. We know that it is "hearing," but that it does a lot of filtering and signal processing, so that it will only respond to the kinds of sounds it knows are important. Mothers, for example, become sensitive to the softest cries of their babies when they need to be fed, but will ignore the louder noise of an airplane flying overhead at four in the morning. A lot of this filtering is going on in a region of the brain called the thalamus. We don't understand the mechanism, though, and we certainly don't understand how the brain decides what's important and what's not important. It is a quite amazing ability. Snorers can reach eighty decibels, louder than a barking dog, and sleep through the whole thing. When you play them a tape of themselves snoring, they can't believe they are able to sleep through it. Of course, an interesting question is, if the snorer's brain can ignore the noise, then why can't the brain of the person lying next to them do the same thing? The answer is that it can and often does. Snoring is very common, especially in Canada, it seems. In a study done in Toronto several years ago, about 80 per cent of wives claimed that their husbands snored. Other studies from around the world have found that about 30 per cent of adult men and about 15 per cent of women snore. There would be a lot of sleep-deprived women and men out there if they could not adapt to their partner's snoring. Studies have shown that if the bed partner can fall asleep before the snorer, she or he will very often sleep through the snoring. However, the bed partner who doesn't fall asleep before the snoring spouse may be doomed for the night, since the unconscious mind seems to be better than the conscious mind at filtering out that infernal racket. Sticky Feet Why don't flies fall off the ceiling? Dr. Hugh Danks, Entomologist with the Canadian Museum of Nature in Ottawa: The first thing to note is that flies are light in weight and they're small in size. They have an external skeleton that is relatively light, and, in contrast, humans have a heavy internal skeleton made of bones. If we were to try to hang from the ceiling, we would need some pretty sophisticated hardware. But flies are light, so they don't need the hardware. They are light enough that they aren't really fighting much gravity to stay suspended. Flies use tiny pads on their feet to hang from the ceiling. Each foot has a couple of claws, mainly used for hanging on to rough surfaces, and two tiny pads that allow them to attach themselves tMcDonald, Bob is the author of 'Quirks & Quarks Question Book 101 Answers to Listeners' Questions' with ISBN 9780771054488 and ISBN 0771054483.