Unsurprisingly, strong body odour is generally a turn-off, which scientists think may be due to such smells telling our brains that the person might have a medical issue and therefore, make an unsuitable mate. Not the sort of thing you can assess over Zoom.

Micro-movements

When we meet someone romantically for the first time, our brains are working overtime, interpreting even the smallest movements for signs of interest or sexual attraction, says Hellyer.

“We are trained to read the micro-connections in people’s faces,” she says. “That’s why Botox and plastic surgery can cause problems – we can’t read each other’s faces. We get so much information through these micro-expressions, such as a sense of someone’s integrity, their warmth and vitality.”

At a macro level, the way a potential partner moves can be a turn on, or off, regardless of the objective attractiveness of their features. Some studies have shown that “good” male dancers receive more visual attention from women, who also perceive them as more attractive. Time to work on those dance moves.

Voice

Sometimes you spot someone across a crowded room (or a crowded dating app) and feel an instant connection. And then they open their mouth. Voice, it turns out, is an incredibly powerful indicator of sexual attraction, says Hellyer. There’s even a saying attached to it: men fall in love with their eyes, women fall in love with their ears. Just as with movement, the sound of someone’s voice is only something you can fully experience when you’re in the same space.

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“We get a lot of information through the phone but it is still dulled compared with real life,” she says. “Online, you don’t get the micro-movements. It’s great but it’s not as good as real life, and it’s the same with sound.

“You don’t get that richness and complexity, and it’s the combination of those things that creates attraction.”

What sounds attractive to one person could be very different to someone else but in general, straight men prefer women with higher voices and straight women prefer men with deeper tones. But more than one budding romance has ended – or been kindled – because of a man’s voice or a woman’s laugh.

Mirroring

We human beings are strange in so many ways, with a penchant for symmetry apparently built into our psyche. Mirroring, where one person subconsciously copies the behaviour of the other, is another indicator of sexual interest. Hellyer says it sends powerful signals.

“When we’re with someone we feel comfortable with, we get into a movement synchronicity with them,” she says. “It might be crossing legs in the same way or putting your hand to your face when they do.”

The desire to touch the other person is another strong indicator of sexual interest.

“When we feel good, we fall into these patterns. But we don’t get a chance to do that until we’re in the same space,” she says.

If it’s making online dating sound a bit depressing, Hellyer says nothing could be further from the truth. In fact, pressing pause on making rash judgements based on a single image in a dating profile can open up the possibilities. Even if they look nothing like your celebrity crush, taking your time to read the profile before moving on may help you better understand who they are.

“The visuals are important but particularly if you are dating later in life, it’s not everything,” she says. “If you are going to be dating someone, you need a real sense of the person.”

Just as you would if you were preparing to go to a club to meet new people, she says you should approach online dating when you’re feeling in a good mood and have some time to devote to it.

“Every time you look at a photo of someone, unless it is an immediate ‘no’, like another man holding a fish – which is a definite swipe left – just sit with it for a moment, read the profile and spend a bit of time.”

If you do meet someone and exchange messages, Hellyer says don’t drag it out.

“Chat a little bit first to get a sense of them but if it is someone you like, meet them quickly. If you arrange a nice chat over coffee, what is the worst that can happen?”

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