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Risky Business: The Effect of Peer Pressure on Virginity Loss
The Add Health survey that was conducted among US adolescents has been widely cited in the media recently. It was this data set that got evolutionary biologist Satoshi Kanazawa into so much trouble a few weeks ago when he misrepresented the data as proving that black women were less attractive than white women. That blunder aside, the data itself is extremely useful to researchers attempting to unravel the mysteries of adolescent behavior. Economists have recently tapped into an unusual feature of this data, the identification of peer groups within high schools, to directly measure effects of peer pressure on risky behavior. Specifically they ask the question: If a student’s best friend engages in a risky behavior (sex, smoking, marijuana use or truancy) then what is the probability that the friend will engage it the same behavior? Best friends tend to come from similar family situations, be the same race and age and have similar educational goals as well as similar attitudes toward risk. The authors are able to control for these factors and find that if a student’s best friend has had intercourse then the probability that she or he will have had intercourse in the following year is 4.5 percentage points higher than the base line of 14%. The probability of “intimate contact” (essentially making it to third base) increases by 4 percentage points on a base line of 22%. The best friend effect is as large as living in a single parent household or of having parents who did not finish high school – both of which increase the probability that a student has had been sexually active.
What I find interesting about these results is that unlike other risky behaviors that best friends might do together (like smoking or skipping school), this is risky behavior is that they do apart. One explanation is that teens are smoking pot together and that pot smoking leads to a higher rate of sexual activity or that they are drinking together and that this leads to higher rates of sexual activity. It turns out that pot use doesn't increase entrance to sexual activity in teens, so even though having a best friend who smokes pot increases (to a small degree) the probability that the student also smokes this can`t explain the increase in sexual activity. Alternatively while alcohol use increases sexual activity (significantly), surprisingly having a best friend who drinks alcohol does not increase the probably that a student drinks above the baseline. So that isn`t the effect either. My final thought is this. Everyone wants to argue that sexual intercourse among teens is psychologically damaging (we have talked about this before) and increases depression in adolescents. If this is true then why would teens not learn this from their best friends? Other risky behavior that is done together I understand will not lead to learning, but sexual intercourse is sequential – someone has to be the first to do it. If it made teens unhappy, then would that not lead to a decrease in a friend’s probability of having sex in the subsequent year?
Finally, on a somewhat related note, I was sent this fascinating infographic this week on teen pregnancy that I wanted to share with you. Enjoy!
Card, David and Laura Giuliano (2011). “Peer Effects and Multiple Equilibria in the Risky Behavior of Friends.” NBER Working Paper 17088.
Melting ice is turning up bodies on Mt. Everest. This isn't as shocking as you'd think.
- Mt. Everest is the final resting place of about 200 climbers who never made it down.
- Recent glacial melting, caused by climate change, has made many of the bodies previously hidden by ice and snow visible again.
- While many bodies are quite visible and well known, others are renowned for being lost for decades.
People die trying to reach the top of Mt. Everest. While about 5,000 people have gotten to the top and came back down to tell the tale, 300 have not and 200 bodies remain on the mountain. Many of these bodies have been covered by snow and ice over the years, but now with glaciers melting due to climate change some of the long-hidden bodies are reportedly becoming visible again.
Ang Tshering Sherpa, former president of Nepal Mountaineering Association, told the BBC: "Because of global warming, the ice sheet and glaciers are fast melting and the dead bodies that remained buried all these years are now becoming exposed. We have brought down dead bodies of some mountaineers who died in recent years, but the old ones that remained buried are now coming out."
The ice on Everest is melting fast, in 2016 the Nepalese Army had to be called in to drain lakes swollen with glacial-melt that threatened to flood. The Khumbu Glacier is melting so fast that ponds are forming and linking up to create small lakes. Not all the bodies that turn up are made visible by global warming though, glaciers move and snow drifts shift over time so previously hidden bodies are always at risk of coming back into view.
Why leave the bodies there at all? Why not bring people down as soon as they die?
It costs a lot of money to go get a body on the highest mountain in the world, up to $80,000 to be precise. Then there is the problem of actually doing it, since some attempts to retrieve bodies are forced by difficult conditions to abandon their efforts.
Some people, such as mountaineer Alan Arnette, argue that the bodies should be left there. He told the BBC, "Most climbers like to be left on the mountains if they died. So it would be deemed disrespectful to just remove them unless they need to be moved from the climbing route or their families want them."This doesn't stop people from wanting the bodies taken down or dealt with in other ways. David Sharp's body was moved out of sight in 2007. George Mallory's body took 75 years to find and was given an Anglican burial in 1999. Over time, the elements often move bodies away from the main routes up the mountain to more isolated areas where they remain undisturbed.
Everest’s chilling landmarks
The bodies that remain in view are often used as waypoints for the living. Some of them are well-known markers that have earned nicknames.
For instance, the image above is of "Green Boots," the unidentified corpse named for its neon footwear. Widely believed to be the body of Tsewang Paljor, the remains are well known as a guide point for passing mountaineers. Perhaps it is too well known, as the climber David Sharp died next to Green Boots while dozens of people walked past him — many presuming he was the famous corpse.
A large area below the summit has earned the discordant nickname "Rainbow Valley" for being filled with the bright and colorfully dressed corpses of maintainers who never made it back down. The sight of a frozen hand or foot sticking out of the snow is so common that Tshering Pandey Bhote, vice president of Nepal National Mountain Guides Association claimed: "Most climbers are mentally prepared to come across such a sight."
Other bodies are famous for not having been found yet. Andrew "Sandy" Irvine, the climbing partner of George Mallory, may have been one of the first two people to reach the summit of Everest a full 30 years before Edmund Hillary and Tenzing Norgay did it. Since they never made it back down, nobody knows just how close to the top they made it.
Mallory's frozen body was found by chance in the '90s without the Kodak cameras he brought up to record the climb with. It has been speculated that Irvine might have them and Kodak says they could still develop the film if the cameras turn up. Circumstantial evidence suggests that they died on the way back down from the summit, Mallory had his goggles off and a photo of his wife he said he'd put at the peak wasn't in his coat. If Irvine is found with that camera, history books might need rewriting.
As Everest's glaciers melt its morbid history comes into clearer view. Will the melting cause old bodies to become new landmarks? Will Sandy Irvine be found? Only time will tell.
It could lead to a massive uptake in those previously hesitant.
A financial shot in the arm could be just what is needed for Americans unsure about vaccination.
On May 12, 2021, the Republican governor of Ohio, Mike DeWine, announced five US$1 million lottery prizes for those who are vaccinated. Meanwhile, in West Virginia, younger citizens are being enticed to get the shot with $100 savings bonds, and a state university in North Carolina is offering students who get vaccinated a chance to win the cost of housing. Many companies are paying vaccinated employees more money through bonuses or extra paid time off.
The push to get as many people vaccinated as possible is laudable and may well work. But leading behavioral scientists are worried that paying people to vaccinate could backfire if it makes people more skeptical of the shots. And ethicists have argued that it would be wrong, citing concerns over fairness and equity.
As a behavioral scientist and ethicist, I draw on an extensive body of research to help answer these questions. It suggests that incentives might work to save lives and, if properly structured, need not trample individual rights or be a huge expense for the government.
In the United States, incentives and disincentives are already used in health care. The U.S. system of privatized health insurance exposes patients to substantial deductibles and copays, not only to cover costs but to cut down on what could be deemed as wasteful health care – the thinking being that putting a cost to an emergency room visit, for example, might deter those who aren't really in need of that level of care.
In practice, this means patients are encouraged to decline both emergency and more routine care, since both are exposed to costs.
Paying for health behaviors
In the case of COVID-19, the vaccines are already free to consumers, which has undoubtedly encouraged people to be immunized. Studies have shown that reducing out-of-pocket costs can improve adherence to life-sustaining drugs, whether to prevent heart attacks or to manage diabetes.
A payment to take a drug goes one step further than simply reducing costs. And if properly designed, such incentives can change health behaviors.
And for vaccination in particular, payments have been successful for human papillomavirus (HPV) in England; hepatitis B in the United States and the United Kingdom; and tetanus toxoid in Nigeria. The effects can be substantial: For example, for one group in the HPV study, the vaccination rate more than doubled with an incentive.
For COVID-19, there are no field studies to date, but several survey experiments, including one my group conducted with 1,000 Americans, find that incentives are likely to work. In our case, the incentive of a tax break was enough to encourage those hesitant about vaccinations to say they would take the shot.
Even if incentives will save lives by increasing vaccinations, there are still other ethical considerations. A key concern is protecting the autonomous choices of people to decide what they put into their own bodies. This may be especially important for the COVID-19 vaccines, which – although authorized as likely safe and effective – are not yet fully approved by the Food and Drug Administration.
But already people are often paid to participate in clinical trials for drugs that have not yet been approved by the FDA. Ethicists have worried that such payments may be “coercive" if the money is so attractive as to override a person's free choices or make them worse off overall.
One can quibble about whether the term “coercion" applies to offers of payment. But even if offers were coercive, payments may still be reasonable to save lives in a pandemic if they succeed in greater levels of immunization.
During the smallpox epidemic nearly 100 years ago, the U.S. Supreme Court upheld the power of states to mandate vaccines. Compared with mandating vaccination, the incentives to encourage vaccines seem innocuous.
Exploitation and paternalism
Yet some still worry. Bioethicists Emily Largent and Franklin Miller wrote in a recent paper that a payment might “unfairly" exploit “those U.S. residents who have lost jobs … or slipped into poverty during the pandemic," which could leave them feeling as if they have “no choice but to be vaccinated for cash." Others have noted that vaccine hesitancy is higher in nonwhite communities, where incomes tend to be lower, as is trust in the medical establishment.
Ethicists and policymakers should indeed focus on the poorest members of our community and seek to minimize racial disparities in both health outcomes and wealth. But there is no evidence that offering money is actually detrimental to such populations. Receiving money is a good thing. To suggest that we have to protect adults by denying them offers of money may come across as paternalism.
Some ethicists also argue that the money is better spent elsewhere to increase participation. States could spend the money making sure vaccines are convenient to everyone, for example, by bringing them to community events and churches. Money could also support various efforts to fight misinformation and communicate the importance of getting the shot.
The cost of incentives
Financial incentives could be expensive as a policy solution. As in Ohio, lottery drawings are one way to cap the overall cost of incentives while giving millions of people an additional reason to get their shot.
The tax code could also allow for a no-cost incentive for vaccination. Tax deductions and credits are often designed to encourage behaviors, such as savings or home ownership. Some states now have big budget surpluses and are considering tax relief measures. If a state announced now that such payments would be conditional on being vaccinated, then each person declining the shot would save the government money.
Ultimately, a well-designed vaccination incentive can help save lives and need not keep the ethicists up at night.
Geologists discover a rhythm to major geologic events.
- It appears that Earth has a geologic "pulse," with clusters of major events occurring every 27.5 million years.
- Working with the most accurate dating methods available, the authors of the study constructed a new history of the last 260 million years.
- Exactly why these cycles occur remains unknown, but there are some interesting theories.
Our hearts beat at a resting rate of 60 to 100 beats per minute. Lots of other things pulse, too. The colors we see and the pitches we hear, for example, are due to the different wave frequencies ("pulses") of light and sound waves.
Now, a study in the journal Geoscience Frontiers finds that Earth itself has a pulse, with one "beat" every 27.5 million years. That's the rate at which major geological events have been occurring as far back as geologists can tell.
A planetary calendar has 10 dates in red
Credit: Jagoush / Adobe Stock
According to lead author and geologist Michael Rampino of New York University's Department of Biology, "Many geologists believe that geological events are random over time. But our study provides statistical evidence for a common cycle, suggesting that these geologic events are correlated and not random."
The new study is not the first time that there's been a suggestion of a planetary geologic cycle, but it's only with recent refinements in radioisotopic dating techniques that there's evidence supporting the theory. The authors of the study collected the latest, best dating for 89 known geologic events over the last 260 million years:
- 29 sea level fluctuations
- 12 marine extinctions
- 9 land-based extinctions
- 10 periods of low ocean oxygenation
- 13 gigantic flood basalt volcanic eruptions
- 8 changes in the rate of seafloor spread
- 8 times there were global pulsations in interplate magmatism
The dates provided the scientists a new timetable of Earth's geologic history.
Tick, tick, boom
Credit: New York University
Putting all the events together, the scientists performed a series of statistical analyses that revealed that events tend to cluster around 10 different dates, with peak activity occurring every 27.5 million years. Between the ten busy periods, the number of events dropped sharply, approaching zero.
Perhaps the most fascinating question that remains unanswered for now is exactly why this is happening. The authors of the study suggest two possibilities:
"The correlations and cyclicity seen in the geologic episodes may be entirely a function of global internal Earth dynamics affecting global tectonics and climate, but similar cycles in the Earth's orbit in the Solar System and in the Galaxy might be pacing these events. Whatever the origins of these cyclical episodes, their occurrences support the case for a largely periodic, coordinated, and intermittently catastrophic geologic record, which is quite different from the views held by most geologists."
Assuming the researchers' calculations are at least roughly correct — the authors note that different statistical formulas may result in further refinement of their conclusions — there's no need to worry that we're about to be thumped by another planetary heartbeat. The last occurred some seven million years ago, meaning the next won't happen for about another 20 million years.