And I'm Beth.

Head over heels, butterflies in the tummy, the apple of my eye. In English there are many idioms to describe what it feels like to fall in love.

Aww, I didn't know you were such a romantic, Neil. But do you know what's actually happening in our brains when we fall in love? Because I'm sorry to say this, Neil, but it's more about brain chemistry than romance. Specifically hormones – chemical messengers which the body releases into the blood to control our growth, mood and, yes, falling in love.

Thanks for ruining my romantic ideas, Beth. And since my dreams are now shattered, why don't we spend the rest of this programme finding out exactly what is going on inside our bodies and brains when we fall in love? And of course, learn some useful new vocabulary too.

There's no doubt that being in love has the health benefit of reducing stress, even lengthening your life. But the hormones which the brain releases have an immediate effect as well.

So, chemically speaking, what happens when lovers look into each other's eyes? Is it… a. Their body temperature increases, b. Their heartbeats harmonise, or c. The hairs stand up on the back of their neck?

Is it all three? No, OK then. I'll guess it's b. Their heartbeats harmonise.

OK. We'll find out if that's correct at the end of the programme. According to Helen E.

Fisher, self-help author and anthropologist at Rutgers University, there are three aspects of romantic love. Here's BBC Ideas to explain more.

Often lust comes first, but not always. For some people who are asexual, it may not happen at all. But for those who do experience lust, it's driven by the hormones oestrogen and testosterone. It may feel purely carnal, but in fact it's about the urge to mate and pass on your DNA via offspring. Without lust, it's fair to say, our species would not survive.

Helen Fisher thinks the first aspect of love is purely physical – lust – the strong feeling of sexual desire for someone. Lust is driven by the hormones oestrogen in women and testosterone in men. A few people are asexual, meaning they don't feel sexual attraction for anyone of any gender. Lust is hardwired into us through our DNA and it drives us to have children.

Helen thinks it's fair to say that without lust, our species would not survive. Here, she uses the phrase it's fair to say to introduce an idea she believes to be true and reasonable.

Of course, love is not just physical. Here's BBC Ideas again to introduce Helen Fisher's second aspect of love – attraction.

The second aspect of romantic love is attraction, influenced by a neurotransmitter called dopamine.

This is a feel-good substance released in our brain that is involved in driving us towards reward. Do something. Get a dopamine hit. Feel good. Eventually, dopamine will push us towards repeating that behaviour. This is why intense attraction feels like an addiction to another human being. Some people get stuck in that loop, always chasing the dopamine-soaked excitement of a new relationship. This time, the hormone responsible is dopamine, a neurotransmitter that rewards our attraction to someone with pleasurable feelings. That's why dopamine is called a feel-good substance. The adjective feel-good can be used to describe anything causing happy and optimistic feelings about life – things like feel-good films or feel-good music.

Here, though, there's a downside. The dopamine hit of sexual attraction feels so good, we crave it more and more. Some people are always chasing the next relationship to get a new hit of pleasure, and soon become stuck in a loop – an idiom meaning they're unable to break the habit of repeating the same patterns of behaviour over and over again.

It's fascinating to see the power which hormones have over us. But if you're an old-fashioned romantic like Neil, don't despair. And speaking as a romantic, how about the answer to my question?

Right, you asked me about the effect on the body when two lovers look deep into each other's eyes.

I guessed it was that their heartbeats harmonise.

Which was the correct answer! In experiments, looking into the eyes produced hormones causing couples' hearts to beat in time. OK, let's recap the vocabulary we've learnt in this programme, starting with the idiom head over heels – to be completely in love with someone.

Lust is a very strong feeling of sexual desire.

Someone who is asexual does not feel sexual attraction towards anyone of any gender.

The phrase it's fair to say is used to introduce a statement you believe to be true and reasonable.

The adjective feel good describes something which makes people feel happy and optimistic.

And finally, the idiom stuck in a loop describes someone unable to break the habit of repeating the same negative patterns of behaviour over and over again. Once again, our 6 minutes are up, but remember to join us again next time for more topical discussion and useful vocabulary here at 6 Minute English. Goodbye for now.

Bye.

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