Sex lowers your blood-pressure response to stress for days, according to a small study. For two weeks, 46 volunteers "kept diaries of how often they engaged in penile-vaginal intercourse (PVI), masturbation," or other "partnered sexual activity." Then they were assigned public speaking and measured for stress. Results: Those who had PVI "were least stressed, and their blood pressure returned to normal faster than those who'd only masturbated or had non-coital sex. Those who abstained had the highest blood-pressure response." Researchers' theory: The duration of the effect, and the fact that you get more of it from PVI than from other sex, suggests the benefit comes not from orgasm but from oxytocin, a pair-bonding hormone. Translation: It's not the sex; it's the love. Skeptics' suspicions: 1) People who volunteer to record and report their sex acts are not a representative sample. 2) Great, this news will really help us control teen pregnancy. 3) Maybe the low stress causes the sex, not the other way around. 4) This isn't a study; it's a pickup line. (For Human Nature's takes on noncoital sex acts, click here, here, here, or here. For PVI between unauthorized pairs, click here or here. For the costs of abstinence, click here or here. For the pope's take on love and sex, click here.)
The same amount of smoking is more risky for blacks than whites and less risky for Latinos. A study shows the risk of getting lung cancer from smoking a pack a day is 55 percent higher in blacks than in whites, and 50 percent lower in Latinos than in whites. Reactions: 1) This will confirm biological differences between the races and help us customize treatments and prevention efforts. 2) It will confirm biological differences and lend credence to racists. 3) It will let the medical establishment write off lung cancer as a black disease. 4) It will let skeptics explain away health problems in blacks that are really caused by racism. 5) It will free us to address racial health disparities more effectively by focusing on biology instead of racism.
Jews with a genetic mutation have a 1-in-3 chance of having Parkinson's. The mutation causes 18 percent of Parkinson's cases in Ashkenazi Jews and 37 percent of such cases in North African Arabs. Questions: 1) Does this mean Jews and Arabs should be tested for the mutation? 2) Does it reaffirm the bond between Jews and Arabs? 3) Does it mean we'll find genetic causes of Parkinson's in other groups? 4) Does it mean we'll find genetic causes of other diseases?
Female promiscuity gives males big testes and small brains. In bat species noted for female monogamy, males have small testes and big brains; in bat species noted for female promiscuity, males have testicles five times as big, but smaller brains. Testes in one species are 8.5 percent of the male's body weight. Reason for big testicles: If a female is taking sperm from you and another guy, the best way to pass on your genes instead of his is to deliver more sperm. (This is why chimps have testicles "many times larger than those of gorillas.") Reason for small brains: Male bats that spent their energy making sperm beat out the ones that spent their energy thinking. Researchers' conclusion: "Size does matter." (For an article on the importance of male genital size in fish, click here. For human misconceptions about penis size, click here.)
Anti-obesity crusaders are targeting haggis, a Scottish dish made by boiling a sheep's heart, liver, lungs, and windpipe in its stomach. Scottish health officials have put it on a list of "restricted" foods for kids because it has too much salt and fat. Reactions from haggis defenders: 1) It's "all natural," unlike hot dogs. 2) First they came for the smokers; now haggis; what's next? 3) At least we'll still have haggis hurling.
An FDA panel voted to allow over-the-counter sales of a fat-blocking pill. Good news: The drug, orlistat (marketed as Alli), stops your intestines from absorbing one-fourth of the fat you eat. Bad news: 1) To lose weight, you still have to eat less and exercise. 2) If you stop taking the pill, the weight comes back. 3) The pill also blocks absorption of fat-soluble vitamins. 4) Can you guess what your intestines do with the fat they're no longer absorbing? "Fecal incontinence, gas and oily discharge ... spotted the undergarments of trial participants." FDA panel chairman's question to executives: "Have you considered placing a warning on the box, 'Don't take this product while wearing your new La Perla underwear?' " Rebuttal: You'll lose even more weight, because the prospect of "anal leakage" will kill your interest in ice cream.
Brain scans confirm the irrationality of partisan political thinking. MRIs of 30 partisan Democrats and Republicans show each group judging flip-flops by the other's candidate (Bush or Kerry) harshly. But when exposed to flip-flops by its own candidate, each group shows activation of brain regions that regulate negative feelings, administer forgiveness, and express relief and happiness. "The 'cold reasoning' regions of the cortex were relatively quiet."
Rich people are freezing their bodies and leaving their money to themselves. According to the Wall Street Journal, 142 people have had their heads or bodies frozen, roughly 1,000 have made similar arrangements, and at least a dozen (the rest are keeping mum, according to participants) have set up "revival trusts." The idea is to accrue wealth and shield it from taxes so you can collect it if scientists figure out how to revive you and keep you alive. More than 20 states permit "dynasty trusts" that can last centuries; lawyers are amending these to let the deceased collect if he returns. Questions: 1) Can your clone collect the money, or do doctors have to bring you back with your memories? 2) Do you have to return your life insurance payout? 3) If they figure out how to revive and cure you, isn't that good fortune enough? (For Human Nature's previous update on freezing and reviving people, click here.) (WSJ link requires subscription.)
Ears may have evolved for breathing. 1) Fossils of a prehistoric fish related to early land animals show a widening earlike cavity unconnected to the inner ear, which means the cavity had another purpose. 2) The cavity resembles blowholes of today's sharks and rays. 3) Early land animals had the same cavity but apparently no eardrums. 4) Later land animals added eardrums, since sound is harder to hear on land than in water. Researchers' theory: Ears originated in water for breathing, then evolved on land for hearing. Conclusions: 1) Creationists are wrong to suggest that organs are "irreducibly complex," i.e., can't evolve in stages unrelated to their current function. 2) "It's hard to believe that if God wanted to design an ear, this is the way He'd go about it." (For Human Nature's take on creationism and irreducible complexity, click here.)
Latest Human Nature columns: 1) Men, women, and the joy of punishment. 2) Scalia on abortion and suicide. 3) Teachers who have sex withboys. 4) Our creepy genetic experiment on dogs. 5) The pope's anti-gay tendencies. 6) Does Alito treat women like girls? 7) Bill Bennett's racial determinism. 8) The mainstreaming of anal sex. (Click here to return to top of page.)