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  • Over 1.5 billion people use the internet every day, and they search for pretty much anything.

  • Like "Why are barns red?" andWhat's up with gluten?”We here at SciShow are all about fostering curiosity.

  • That's why we've worked with Google and YouTube to answer ten of the most popular questions searched on the internet.

  • This is The World's Most Asked Questions.

  • Today's question: What is love?

  • It's the kind of thing that keeps poets and philosophers up at night,

  • but science actually has a pretty good explanation for it, too.

  • Actually, several explanations.

  • And the answer might change depending on what kind of scientist you ask.

  • A biologist would say it's all about reproduction, and the evolution and survival of a species.

  • A psychologist may go on about our need for togetherness and acceptance.

  • But possibly the best way to understand love is through chemistry. Brain chemistry.

  • Although the heart is our symbol of love for some reason,

  • when it comes down to it, love is all about the brain.

  • We know this because we can actually see love in action in brain scans.

  • And you know what? It looks awful like a brain on cocaine.

  • As a person first falls in love, at least a dozen different brain parts light up to release powerful chemicals --hormones and neurotransmitters

  • that trigger feelings of excitement, euphoria, bonding, and butterflies.

  • Research also shows that the kind of unconditional love between a mother and child activates slightly different regions of the brain.

  • Early romantic love and attraction, what you might call passion, is all about flooding the brain's reward systems

  • in a tsunami of feel-good chemicals like adrenaline, norepinephrine, and dopamine.

  • This is why a brain on intense new love looks a whole lot like a brain on coke

  • adrenaline and norepinephrine amp up your heart rate and get you all restless,

  • while those dopamine drips leave you feeling euphoric.

  • These chemicals light up your brain's pleasure centers, lowering your pleasure thresholds,

  • and making it easier to feel good about...everything.

  • Interestingly, this kind of passionate new love is also marked by lowered serotonin levels,

  • similar to those found in people with obsessive-compulsive disorders

  • which may help explain those 30 texts your infatuated new lover sent while you were in the shower.

  • Eventually, most of these more intense, obsessive components of new love settle down

  • into a deeper, calmer form of love associated with attachment and bonding.

  • Here your brain chemistry starts changing again, and hormones like oxytocin and vasopressin take over.

  • Their mission, like Al Green's, is to get you to stay together.

  • You may have heard of oxytocin, the so-called the "cuddle hormone."

  • It gets released during orgasms, and for women during childbirth, and it helps cement bonds between people.

  • And you can think of vasopressin as the monogamy hormone.

  • And you know who's taught us more about how it works than anything else?

  • Prairie voles, one of the very few mammals that mate for life.

  • After mating, a male vole's brain gets flooded with vasopressin, and essentially gets hooked on his mate forever.

  • The two then have lots of sex, and all that tiny boot-knocking keeps the vasopressin flowing.

  • When researchers gave voles a compound that suppressed the effects of vasopressin,

  • the pairs quicklyfell apart, losing their devotion to each other.

  • So, while in the poetic sense, love may always be something of a mystery,

  • from the scientific view, it is within the realm of comprehension.

  • But what about you? How are the love lives of the SciShow viewers?

  • Well, of our survey takers, people within the ages of 51 and 60 are the most likely to have been in love.

  • People who got their energy most from exercise were also more likely to have been in love.

  • On the other hand, people who said they got their energy from food were less likely to have been in love.

  • Of all the fascinating questions in the world, what question do you want answered most?

  • Let us know on Facebook or Twitter or in the comments down below, and we will answer the best questions in a new video at the end of the month.

  • And don't forget to use the hashtag #WMAQ and stay tuned for other videos this week.

Over 1.5 billion people use the internet every day, and they search for pretty much anything.

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B1 INT US brain love norepinephrine chemistry dopamine obsessive

World’s Most Asked Questions: What Is Love?

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    Halu Hsieh   posted on 2015/02/13
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