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How Statistics Fool Juries

Peter Donnelly is a statistician with a sense of humor. He starts his talk with a classic statistician joke: "How do you tell an introverted statistician from an extroverted statistician? The extrovert is the one who looks at the other person's shoes." But he's not all fun and games. In a 2005 TED Talk, Donnelly explains a little about with it's like to be a professional statistician, then launches into a fascinating explanation of how statistics are misunderstood by typical audiences. He gives examples for the audience to examine (a few multiple-choice questions), to prove his point -- and I'll admit, he got me. I didn't get the examples right, though I was pretty confident in my answers.

This reminds me of when I was on a jury room in a personal injury case. While my experience wasn't related to statistics, it was an issue of science which seemed like we should have been able to prove the right answer one way or another -- but we failed. The jury had an hour-long argument about physics, trying to determine whether a driver's upper body in a car would be pushed forward or backward when the car was hit from behind. (There was a key question regarding whether a specific injury could have been caused by the impact, or was a pre-existing condition.) We even built a model, but that failed to convince anybody of what the real-world behavior would be. Everyone on the jury insisted that his or her own mental model was correct (which tended to align with their gut feeling about the guilt or innocence of the defendant), and neither demonstrating the physics of the situation, nor thinking through it with a shared mental model made any difference. It was an interesting day, to say the least. (See also: whiplash.)

Anyway, Donnelly's talk is a great example of how attorneys (or really anyone) can exploit general misunderstanding of statistics in order to make an invalid point -- and most of us won't notice that anything is wrong. There's even a term for one specific statistical misuse, the prosecutor's fallacy, and Donnelly explains how it was exploited in the Sally Clark case. Definitely worth a look!

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Art
The Simple Optical Illusion That Makes an Image Look Like It's Drawing Itself
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Artist James Nolan Gandy invents robot arms that sketch intricate mathematical shapes with pen and paper. When viewed in real time, the effect is impressive. But it becomes even more so when the videos are sped up in a timelapse. If you look closely in the video below, the illustration appears to materialize faster than the robot can put the design to paper. Gizmodo recently explained how the illusion works to make it look like parts of the sketch are forming before the machine has time to draw them.

The optical illusion isn’t an example of tricky image editing: It’s the result of something called the wagon wheel effect. You can observe this in a car wheel accelerating down the highway or in propeller blades lifting up a helicopter. If an object makes enough rotations per second, it can appear to slow down, move backwards, or even stand still.

This is especially apparent on film. Every “moving image” we see on a screen is an illusion caused by the brain filling in the gaps between a sequence of still images. In the case of the timelapse video below, the camera captured the right amount of images, in the right order, to depict the pen as moving more slowly than it did in real life. But unlike the pen, the drawing formed throughout the video isn't subject to the wagon-wheel effect, so it still appears to move at full speed. This difference makes it look like the sketch is drawing itself, no pen required.

Gandy frequently shares behind-the-scenes videos of his mechanical art on his Instagram page. You can check out some of his non-timelapse clips like the one below to better understand how his machines work, then visit his website to browse and purchase the art made by his 'bots.

And if you think his stuff is impressive, make sure to explore some of the incredible art robots have made in the past.

[h/t Gizmodo]

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science
Narcissists Are More Likely to Be Compulsive Facebook Users
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Updating your Facebook status throughout the day is probably a sign you need a different hobby, but according to a new study, the habit can also indicate something else. As PsyPost reports, people with Facebook addiction are also likely to be narcissists.

For their recent study published in the journal PLOS One, scientists from Ruhr-Universität Bochum in Germany followed the Facebook activity of 179 German students over the course of a year. They were looking for cases of so-called Facebook Addiction Disorder (FAD) based on the Bergen Facebook Addiction Scale, a system developed by University of Bergen researchers that measures factors like mood modification, withdrawal, and relapse in relation to Facebook use.

They wanted to find out whether FAD was linked to other mental health problems. In addition to gauging Facebook compulsion, they also surveyed subjects on their depression and anxiety levels, social support systems, physical health, narcissism, and general satisfaction with life. The results showed a strong correlation between FAD and narcissism. Rather than Facebook making its users more narcissistic, the researchers state that people with narcissistic personalities are at a greater risk of developing the social media addiction.

"Facebook use holds a particular meaning for narcissistic people," they write in the paper. "On Facebook, they can quickly initiate many superficial relationships with new Facebook-friends and get a large audience for their well-planned self-presentation. The more Facebook-friends they have, the higher is the possibility that they attain the popularity and admiration they are seeking; whereas in the offline world they might not be as popular since their interaction partners can quickly perceive their low agreeableness and exaggerated sense of self-importance."

The researchers also found a connection between Facebook addiction and higher levels of stress, depression, and anxiety.

Studies investigating Facebook Addiction Disorder have been conducted in the past, but there’s still not enough research to classify it as an official behavioral addiction. The researchers hope their work will lead to similar studies pinning down a link between FAD and mental health consequences.

[h/t PsyPost]

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