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Why Can't You Tickle Yourself?

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By Chris Gayomali

It's darn near impossible to tickle yourself, and the mechanics behind the non-phenomenon of self-tickling are pretty straightforward: Your subconscious mind is always one step ahead of you. Your "unexpected" touch, no matter how cleverly you disguise it, is almost always expected—and that's largely a good thing. Here's how Sara-Jayne Blakemore, a researcher at the Institute of Cognitive Neuroscience at University College London, explained it to Scientific American in 2007:

…the cerebellum can predict sensations when your own movement causes them but not when someone else does. When you try to tickle yourself, the cerebellum predicts the sensation and this prediction is used to cancel the response of other brain areas to the tickle.

Two brain regions are involved in processing how tickling feels. The somatosensory cortex processes touch and the anterior cingulate cortex processes pleasant information. We found that both these regions are less active during self-tickling than they are during tickling performed by someone else, which helps to explains why it doesn't feel tickly and pleasant when you tickle yourself. [Scientific American]

The brain is programmed to anticipate unimportant sensations, like your rear against a comfy chair or the socks on your feet. It saves those valuable synapses for the weird and unexpected, like when there's a poisonous spider crawling down the back of your shirt.

Our utter imperviousness to the self-tickle can even conquer technology intended to camouflage it, to an extent. In a recent interview with NPR, professor Jakob Hohwy, a philosophy researcher at Monash University in Australia, outlines a bizarre and wonderfully elaborate experiment designed to trick the brain.

HOST: In his tickling experiment, Hohwy used his own version of the rubber hand trick. He made his subjects wear a pair of video goggles hooked up to a camera on another person's head. And with good old fashioned synchrony, he got them to feel, as if they were actually the person sitting across the table. And in that moment he had them try to tickle their palm.

HOHWY: And then we ask, how ticklish is it? And it turns out that when they do it themselves, they still can't tickle themselves. [NPR]

There is, however, a lone exception to the no-tickling rule: Schizophrenics have the notable ability to tickle themselves on demand. One theory, according to Hohwy, is that "people with schizophrenia are relatively poor at predicting what the sensory consequences will be of their own movement." Somewhere between the triangulation of fingers, eyes, and the unconscious mind, the electrical signals beamed back to the brain hit a snag.

In many ways, our silly inability to self-tickle showcases the powerful machinery of the human mind at its most efficient: Your brain is in a constant state of trying to predict what's about to happen next. It's always one step ahead and looking to the future, even if you necessarily aren't.

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science
6 Radiant Facts About Irène Joliot-Curie
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Though her accomplishments are often overshadowed by those of her parents, the elder daughter of Marie and Pierre Curie was a brilliant researcher in her own right.

1. SHE WAS BORN TO, AND FOR, GREATNESS.

A black and white photo of Irene and Marie Curie in the laboratory in 1925.
Irène and Marie in the laboratory, 1925.
Wellcome Images, Wikimedia Commons // CC BY 4.0

Irène’s birth in Paris in 1897 launched what would become a world-changing scientific dynasty. A restless Marie rejoined her loving husband in the laboratory shortly after the baby’s arrival. Over the next 10 years, the Curies discovered radium and polonium, founded the science of radioactivity, welcomed a second daughter, Eve, and won a Nobel Prize in Physics. The Curies expected their daughters to excel in their education and their work. And excel they did; by 1925, Irène had a doctorate in chemistry and was working in her mother’s laboratory.

2. HER PARENTS' MARRIAGE WAS A MODEL FOR HER OWN.

Like her mother, Irène fell in love in the lab—both with her work and with another scientist. Frédéric Joliot joined the Curie team as an assistant. He and Irène quickly bonded over shared interests in sports, the arts, and human rights. The two began collaborating on research and soon married, equitably combining their names and signing their work Irène and Frédéric Joliot-Curie.

3. SHE AND HER HUSBAND WERE AN UNSTOPPABLE PAIR.

Black and white photo of Irène and Fréderic Joliot-Curie working side by side in their laboratory.
Bibliothèque Nationale de France, Wikimedia Commons // Public Domain

Their passion for exploration drove them ever onward into exciting new territory. A decade of experimentation yielded advances in several disciplines. They learned how the thyroid gland absorbs radioiodine and how the body metabolizes radioactive phosphates. They found ways to coax radioactive isotopes from ordinarily non-radioactive materials—a discovery that would eventually enable both nuclear power and atomic weaponry, and one that earned them the Nobel Prize in Chemistry in 1935.

4. THEY FOUGHT FOR JUSTICE AND PEACE.

The humanist principles that initially drew Irène and Frédéric together only deepened as they grew older. Both were proud members of the Socialist Party and the Comité de Vigilance des Intellectuels Antifascistes (Vigilance Committee of Anti-Fascist Intellectuals). They took great pains to keep atomic research out of Nazi hands, sealing and hiding their research as Germany occupied their country, Irène also served as undersecretary of state for scientific research of the Popular Front government.

5. SHE WAS NOT CONTENT WITH THE STATUS QUO.

Irène eventually scaled back her time in the lab to raise her children Hélène and Pierre. But she never slowed down, nor did she stop fighting for equality and freedom for all. Especially active in women’s rights groups, she became a member of the Comité National de l'Union des Femmes Françaises and the World Peace Council.

6. SHE WORKED HERSELF TO DEATH.

Irène’s extraordinary life was a mirror of her mother’s. Tragically, her death was, too. Years of watching radiation poisoning and cancer taking their toll on Marie never dissuaded Irène from her work. In 1956, dying of leukemia, she entered the Curie Hospital, where she followed her mother’s luminous footsteps into the great beyond.

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You Can Now Order Food Through Facebook
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After a bit of controversy over its way of aggregating news feeds and some questionable content censoring policies, it’s nice to have Facebook roll out a feature everyone can agree on: allowing you to order food without leaving the social media site.

According to a press release, Facebook says that the company decided to begin offering food delivery options after realizing that many of its users come to the social media hub to rate and discuss local eateries. Rather than hop from Facebook to the restaurant or a delivery service, you’ll be able to stay within the app and select from a menu of food choices. Just click “Order Food” from the Explore menu on a desktop interface or under the “More” option on Android or iOS devices. There, you’ll be presented with options that will accept takeout or delivery orders, as well as businesses participating with services like Delivery.com or EatStreet.

If you need to sign up and create an account with Delivery.com or Jimmy John’s, for example, you can do that without leaving Facebook. The feature is expected to be available nationally, effective immediately.

[h/t Forbes]

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