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5 Takeaways From the Study That Found Second-Born Boys Get Into More Trouble

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Researchers have tried to understand how siblings' birth order affects their competitiveness, intelligence, kindness and other personality traits for more than a century. Now, a new study [PDF] backs up what plenty of older siblings have long argued: their younger brothers are more prone to get in trouble. Here are five takeaways from the thought-provoking research.

1. SECOND-BORN SIBLINGS ARE MORE LIKELY TO GET IN SERIOUS TROUBLE.

The study focused mostly on older brother/young brother and older sister/younger brother sets of siblings. Among two brothers, the younger boys were found to be 20 to 40 percent more likely to be disciplined in school or get in trouble with the law compared to the older boys. As study co-author Joseph Doyle, an economist at MIT, told NPR, "I find the results to be remarkable that the second-born children, compared to their older siblings, are much more likely to end up in prison, much more likely to get suspended in school."

2. THE EFFECT WAS MORE PRONOUNCED FOR BOYS.

Doyle and his colleagues didn't find the same trend among second-born girls with older brothers or sisters. Boys and girls have different rates of delinquency; in this study, the average number of delinquent first-born girls in sister pairs was 54 to almost 100 percent lower than first-born boys in brother pairs. "The gaps in delinquency are smaller when we investigate the effect of being a second-born girl," they write.

3. THE RESULTS WERE SIMILAR IN DIFFERENT ENVIRONMENTS.

The researchers used birth registries in Denmark and in Florida that identified siblings so birth order could be determined. Then, they compared that data to school records, criminal databases, and medical or public health records. Despite differences in racial demographics, education levels, parental employment, and approaches to crime and punishment between the two locales, the researchers found that "second-born boys are substantially more likely to exhibit delinquency problems compared to older siblings" in both Denmark and Florida.

4. FAMILY DYNAMICS PROBABLY PLAY A PART.

Among the families studied, first-born and second-born siblings were equally healthy and achieved similar levels of education, so those factors did not play a large part in explaining the younger kids' propensity for trouble. Instead, the researchers suggest there is less maternal attention paid to second-born children. First-born children "experience their mothers' maternity leaves … both following their own births as well as following the births of the second-born." In other words, Jan Brady might have been right about her sister Marcia.

5. OTHER STUDIES HAVEN'T UNCOVERED THE SAME LINK.

Previous studies have found little connection between certain personality traits or intelligence and the order in which siblings were born. A 2013 paper suggested that "contrary to popular belief, the relationship between birth order and delinquency is spurious." When it comes to interpreting the effects of birth order, researchers are still—metaphorically, at least—fighting over the TV remote.

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'Lime Disease' Could Give You a Nasty Rash This Summer
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A cold Corona or virgin margarita is best enjoyed by the pool, but watch where you’re squeezing those limes. As Slate illustrates in a new video, there’s a lesser-known “lime disease,” and it can give you a nasty skin rash if you’re not careful.

When lime juice comes into contact with your skin and is then exposed to UV rays, it can cause a chemical reaction that results in phytophotodermatitis. It looks a little like a poison ivy reaction or sun poisoning, and some of the symptoms include redness, blistering, and inflammation. It’s the same reaction caused by a corrosive sap on the giant hogweed, an invasive weed that’s spreading throughout the U.S.

"Lime disease" may sound random, but it’s a lot more common than you might think. Dermatologist Barry D. Goldman tells Slate he sees cases of the skin condition almost daily in the summer. Some people have even reported receiving second-degree burns as a result of the citric acid from lime juice. According to the Mayo Clinic, the chemical that causes phytophotodermatitis can also be found in wild parsnip, wild dill, wild parsley, buttercups, and other citrus fruits.

To play it safe, keep your limes confined to the great indoors or wash your hands with soap after handling the fruit. You can learn more about phytophotodermatitis by checking out Slate’s video below.

[h/t Slate]

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Why Eating From a Smaller Plate Might Not Be an Effective Dieting Trick 
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It might be time to rewrite the diet books. Israeli psychologists have cast doubt on the widespread belief that eating from smaller plates helps you control food portions and feel fuller, Scientific American reports.

Past studies have shown that this mind trick, called the Delboeuf illusion, influences the amount of food that people eat. In one 2012 study, participants who were given larger bowls ended up eating more soup overall than those given smaller bowls.

However, researchers from Ben-Gurion University in Negev, Israel, concluded in a study published in the journal Appetite that the effectiveness of the illusion depends on how empty your stomach is. The team of scientists studied two groups of participants: one that ate three hours before the experiment, and another that ate one hour prior. When participants were shown images of pizzas on serving trays of varying sizes, the group that hadn’t eaten in several hours was more accurate in assessing the size of pizzas. In other words, the hungrier they were, the less likely they were to be fooled by the different trays.

However, both groups were equally tricked by the illusion when they were asked to estimate the size of non-food objects, such as black circles inside of white circles and hubcaps within tires. Researchers say this demonstrates that motivational factors, like appetite, affects how we perceive food. The findings also dovetail with the results of an earlier study, which concluded that overweight people are less likely to fall for the illusion than people of a normal weight.

So go ahead and get a large plate every now and then. At the very least, it may save you a second trip to the buffet table.

[h/t Scientific American]

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