A Partner's Touch Could Ease Our Pain

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Those corny old love songs might be on to something after all. Scientists say the touch of a partner’s hand can both relieve pain and restore the physiological connection that pain interrupts. They published their findings in the journal Nature Scientific Reports.

Social animals love living in synch. Fireflies flash at the same time; predators prowl in unison toward their prey. Friends walking together unconsciously fall in step. Choir members’ hearts beat as one when they sing. Scientists believe these rhythmic connections may have developed to strengthen the community and the individual, making both more resilient and more likely to survive.

The same may be true of touch, a force so powerful that animals in experiments consistently choose it over food.

Pain researcher Pavel Goldstein of Cognitive and Affective Neuroscience Lab at CU Boulder had both these ideas on his mind in the delivery room as his wife gave birth to their daughter.

"My wife was in pain," he said in a statement, "and all I could think was, 'What can I do to help her?' I reached for her hand and it seemed to help," he recalls. "I wanted to test it out in the lab: Can one really decrease pain with touch, and if so, how?"

Goldstein and his colleagues set up a simple experiment, recruiting 22 long-term heterosexual couples. They brought the couples into the lab and hooked each person up to instruments to measure their heartbeat and breath. Some of the couples sat together, holding hands; some sat slightly apart; and some were seated in separate rooms.

Then the researchers zapped each woman’s forearm with a low amount of heat, just enough to cause pain, for 2 minutes.

Before the pain began, couples who sat in the same room experienced a concrete physiological connection. Their heartbeats and their breathing rates synched.

Then the pain came, and that connection went away—unless they were holding hands.

The same physical contact was also associated with decreased pain levels. Women hurt less when the men they loved took their hands.

The researchers can't say for sure why this is the case. "It could be that touch is a tool for communicating empathy, resulting in an analgesic, or pain-killing, effect," Goldstein said.

This study had its limitations. It was very small, and all the participants were young (23–32 years old). The experiments didn’t explore what would happen to men in pain, nor did they consider the question in same-gender couples. More research is certainly needed to validate these results. But for now, if someone you love is hurting, well, you know what to do.

This 'Time-Traveling Illusion' Is Designed to Trick Your Brain

A team of researchers from the California Institute of Technology (Caltech) have designed an illusion that might trick your brain into seeing things that aren’t there, the New Atlas reports.

Dubbed the Illusory Rabbit, it provides instructions that are simple enough to follow. Start playing the YouTube video below and look at the cross in the middle of the screen while also watching for flashes that appear at the bottom of the screen. Most importantly, you’ll want to add up the number of flashes you see throughout the video. (And make sure your volume is up.)

We don’t want to spoil the fun, so before we explain the science of how it works, check out the video and try it for yourself.

Did you see three flashes paired with three beeps? You’re not alone. This is due to a phenomenon called postdiction, which is a little like the opposite of prediction. According to a paper outlining these findings in the journal PLOS ONE, postdiction occurs when the brain processes information retroactively [PDF]. This occurs in such a way that our perception of earlier events is altered by stimuli that come later. In this case, you might think you missed the flash paired with the second of the three beeps, so your mind goes back and tries to make sense of the missing information. That's why you may see an “illusory flash” in the middle of the screen, sandwiched between the two real flashes.

For this reason, the researchers call the mind trick a “time-traveling illusion across multiple senses” (in this case, vision and hearing). It’s successful because the beeps and flashes occur so rapidly—in less than one-fifth of a second. The senses essentially get confused, and the brain tries to fill in the gaps retroactively.

"Illusions are a really interesting window into the brain," the paper’s first author, Noelle Stiles, said in a statement. "By investigating illusions, we can study the brain's decision-making process.” Researchers wanted to find out how the brain “determines reality” when a couple of your senses (in this case, sight and hearing) are bombarded with noisy and conflicting information. When the brain isn’t sure of what’s going on, it essentially makes up information.

“The brain uses assumptions about the environment to solve this problem,” Stiles said. “When these assumptions happen to be wrong, illusions can occur as the brain tries to make the best sense of a confusing situation. We can use these illusions to unveil the underlying inferences that the brain makes."

[h/t New Atlas]

How Did 6 Feet Become the Standard Grave Depth?

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It all started with the plague: The origins of “six feet under” come from a 1665 outbreak in England. As the disease swept the country, the mayor of London literally laid down the law about how to deal with the bodies to avoid further infections. Among his specifications—made in “Orders Conceived and Published by the Lord Mayor and Aldermen of the City of London, Concerning the Infection of the Plague”—was that “all the graves shall be at least six feet deep.”

The law eventually fell out of favor both in England and its colonies. Modern American burial laws vary from state to state, though many states simply require a minimum of 18 inches of soil on top of the casket or burial vault (or two feet of soil if the body is not enclosed in anything). Given an 18-inch dirt buffer and the height of the average casket (which appears to be approximately 30 inches), a grave as shallow as four feet would be fine.

A typical modern burial involves a body pumped full of chemical preservatives sealed inside a sturdy metal casket, which is itself sealed inside a steel or cement burial vault. It’s less of a hospitable environment for microbes than the grave used to be. For untypical burials, though—where the body isn’t embalmed, a vault isn’t used, or the casket is wood instead of metal or is foregone entirely—even these less strict burial standards provide a measure of safety and comfort. Without any protection, and subjected to a few years of soil erosion, the bones of the dearly departed could inconveniently and unexpectedly surface or get too close to the living, scaring people and acting as disease vectors. The minimum depth helps keep the dead down where they belong.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

This article originally appeared in 2012.

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