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Why Sisters Are Scientifically Better Than Brothers (and Other Important Discoveries)

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If you're keeping tabs on the score between robots and humans, you've probably heard about the robot named Adam who made a scientific discovery back in April without any human assistance. Well, sort of. He made the discovery after some human scientists gave him a specific project to work on. And while the event was chalked up as a win in the artificial intelligence column, we're here to tell you that Adam's still got a lot of catching up to do before he's doing the work of real human scientists. Need proof? From definitive proof on why sisters are better than brothers to the reasons we itch and scratch, here's our monthly round-up of (human!) scientific discoveries you ought to know about.

Science Proves Sisters are Way Better than Brothers?!

New research from the University of Ulster confirms that girls are made of sugar and spice and everything nice. Tony Cassidy, the lead researcher on the project, found sisters make their siblings more optimistic and help families deal with problems in emotionally healthy ways. Families with at least one sister are more cohesive and communicate more often. Girls who grow up with a sister are more independent and achieve more than girls who have brothers. Cassidy surveyed 571 young adults between 17 and 25. He found that sisters have the most positive impact on broken families. Only children scored in the mid-range for happiness while boys who had only brothers were the least happy.

Tony Cassidy, University of Ulster; presentation at the British Psychological Association Annual Conference.

Reducing Autism Cases by 15%

There's good news in the fight against autism: Hakon Hakonarson's new research may drastically reduce the number of autism cases in the world. Hakonarson, a scientist at the University of Pennsylvania, has been running the largest and most exhaustive genetic study on the disorder. He's analyzed DNA from 2,600 autistic children, 2,000 of their family members, and 7,000 healthy controls. Hakonarson's team has found several variations in chromosomes, but one of the most important might be the variation on gene CDH10, which was found in 65 percent of autistic participants. Amazingly, researchers hypothesize that by fixing this variation they could reduce the number of autism cases by 15 percent. They also found that autism was linked strongly to 30 genes, which produce proteins that help brain cells migrate to the correct location and connect to neighboring cells. While it will be years before autism is completely understood, Hakonarson's results have given scientists a foothold since they can now point to 133 genes which directly contribute to the disorder.

Hakon Hakonarson, et al. "Common genetic variants on 5p14.1 associate with autism spectrum disorders," Nature.

Poverty Can Affect Your Memory

Social scientists have long understood that poorer children don't perform as well as their more affluent peers. Researchers know that inadequate schools, infrequent access to health care, and low quality diets contribute to lower academic and career achievement—the so-called income-achievement gap. But two child development experts have also found that the stress of poverty changes brain functioning. Cornell University's Gary Evans and Michelle Schamberg studied 195 poor and middle class Caucasian students. By measuring their stress hormones and blood pressure at age 9 and 13, the researchers found a direct link between poverty and stress. The duo also tested 17-year old students on their memory-- a reliable indicator of reading, language and problem-solving abilities. Children who grew up in poverty recalled 8.5 items while children who were more affluent remembered 9.44 items. The duo theorizes that stress hormones damage grey matter leading to the deficiencies in working memory.

Gary W. Evans and Michelle A. Schamberg "Childhood poverty, chronic stress, and adult working memory," Proceedings of the National Academy of Sciences.

The Science of Scratching

itching-powder.jpgThe next time you complain about your itchy back and feet, remember that you don't have it that bad. In one of the more disturbing accounts we've ever read (if you're squeamish, don't read ahead), a June 2008 New Yorker article by author Atul Gawande introduced the world to M, a woman who had recently suffered from shingles. M, who is also HIV positive, could not stop scratching the right side of her head. She complained to her doctor who prescribed the normal anti-itching remedies, but the feeling wouldn't cease. Her doctor suggested it was a form of OCD, yet OCD medications didn't quell the itch either. Worse still, the condition got so bad that M actually scratched through her skull.


For people suffering from serious itching conditions, scratching does little to stop the sensation. But now, thanks to Glenn Giesler Jr. and Steve Davidson's recent study, we might understand what's going on when you need to itch. Here's how it works: When a mosquito bites your arm, your sensory neurons respond to the histamine by carrying the itch message through the spinal cord to the thalamus in the brain. The thalamus passes the itch message to the cerebral cortex, which produces the itching sensation at the bite. That's what makes you want to scratch the bite. But Giesler and Davidson did something clever. By using primates, Giesler applied histamine to the animals' feet. If the researchers itched the foot after applying the histamine, the message was disrupted in the spinal cord, meaning the brain didn't get the order to create the itching feeling. The hope is that by understanding how scratching and itching works, it will allow researchers to find better solutions soon.

Steve Davidson, Xijing Zhang, Sergey G Khasabov, Donald A Simone and Glenn J Giesler Jr. "Relief of itch by scratching: state-dependent inhibition of primate spinothalamic tract neurons," Nature Neuroscience.

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The Brain Chemistry Behind Your Caffeine Boost
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Whether it’s consumed as coffee, candy, or toothpaste, caffeine is the world’s most popular drug. If you’ve ever wondered how a shot of espresso can make your groggy head feel alert and ready for the day, TED-Ed has the answer.

Caffeine works by hijacking receptors in the brain. The stimulant is nearly the same size and shape as adenosine, an inhibitory neurotransmitter that slows down neural activity. Adenosine builds up as the day goes on, making us feel more tired as the day progresses. When caffeine enters your system, it falls into the receptors meant to catch adenosine, thus keeping you from feeling as sleepy as you would otherwise. The blocked adenosine receptors also leave room for the mood-boosting compound dopamine to settle into its receptors. Those increased dopamine levels lead to the boost in energy and mood you feel after finishing your morning coffee.

For a closer look at how this process works, check out the video below.

[h/t TED-Ed]

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Sophie Nightingale / University of Warwick
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Can You Spot Which Photo Is Fake? Most People Can’t
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Sophie Nightingale / University of Warwick

In a digital world, it’s easier than ever to fool people. Sophisticated Photoshop jobs, social media, and viral news cycles mislead readers into mistaking shots from a Lebanese music video for real scenes of destruction from Aleppo, thinking that Vladimir Putin was the center of attention at the G-20 summit, or believing that Elizabeth Taylor and Marilyn Monroe posed together for a photo shoot in the park.

While it would be nice to tell ourselves that we would never be duped by such fake images, the truth is, most people can’t distinguish between a manipulated photo and a real one. That’s the takeaway from a new study in Cognitive Research: Principle and Implications. As the team at Science reports, the participants were only able to pinpoint fake images two-thirds of the time.

First, psychologists from the University of Warwick asked more than 700 volunteers to look at real and fake images and identify the changes. The researchers used 10 color photographs sourced from Google searches, manipulating them through airbrushing, adding elements in, subtracting elements, and distorting shadows, and shearing trees. They applied each of these five manipulation techniques separately to a portion of the photos, eventually creating 30 manipulated photos and 10 real ones. All the participants saw one of each of the manipulation types in different photos.

An older man stands in the street in front of a house.
Can you spot the differences between the manipulated image at the top of the page and the original version above?
Sophie Nightingale / University of Warwick

The participants performed slightly above chance rates, identifying photos correctly as real only 58 percent of the time and spotting manipulations 66 percent of the time. Even when they did identify a manipulated photo, though, they didn’t necessarily know where it had been altered.

In a second study, the researchers did the same thing, but using photos study co-author Sophie J. Nightingale took with her Nikon camera, controlling for the fact that images found online could be manipulated before the researchers even downloaded them. They then had almost 660 people take an online survey testing their ability to spot fakes. They had to look at photos and label whether it was fake and if they could see where it was manipulated, whether it was fake but they didn’t know where it had been altered, or whether it was an original. At the end of the study, the subjects identified just 62 percent of the fake images correctly.

Woman standing outside
The first image is the original. The second was manipulated to add in a water spout, airbrush the woman's face, and make other slight changes.
Sophie Nightingale / University of Warwick

The results were the same regarding images that had been manipulated in both overtly unrealistic ways and photos that featured more plausible changes. One reason might be the way that our visual system simplifies information. As long as object geometries and shadows are roughly correct, our eyes accept them as accurate.

“It remains to be determined whether it is possible to train people to make use of physically implausible inconsistencies,” the researchers write. “Perhaps one possibility would entail ‘teaching' the visual system to make full use of physical properties of the world as opposed to automatically simplifying them.”

You can still take a 10-minute online survey for the project here and test your own manipulation awareness skills. (I had to take wild guesses on most of them.)

If this makes you weep for the future of the world, at least know that it’s a timeless problem. Manipulated, misleading images have been around since the earliest days of photography.

[h/t Science]

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