I was asked to torture myself for a week for this experiment. Well, not torture, but close enough for me. For a week, this introvert would put social awkwardness to one side and live as an extrovert. I don’t particularly enjoy meeting new people. I decline most party invitations and if I do go, I leave as soon as I can without causing offence. Sometimes I fantasise about doing what Princess Diana used to do when she wanted to lose friends – change her phone number. So the prospect of spending a week saying yes to every social engagement that came my way was about as appealing as a root canal treatment.

But evidence shows that conquering your inner introversion can be good for your mental health. In a recently published study, researchers at the University of California asked 123 people to act as extroverts for a week. Participants were asked to be talkative, assertive and spontaneous in their daily interactions with other people. The following week, the same group was asked to act like introverts. The findings were remarkable.

“It was the biggest effect we’ve ever found in any of our studies,” says Dr Sonja Lyubomirsky, the lead researcher. “When people acted extrovert, they experienced more positive emotions and satisfaction. When they acted introvert, they experienced fewer positive emotions.” She speculates that this is because, at heart, humans are social creatures. “Social relationships are inherently rewarding for us. We have a need to belong and to connect with each other.”

But how to do it? If there is one person to ask, it is Jessica Pan. In 2018, Pan spent a year as an extrovert and documented the experience in a memoir, Sorry I’m Late, I Didn’t Want to Come. “You won’t die,” Pan says. “But you are probably going to be exhausted by the end of the week.” (Unlike extroverts, who draw energy from social encounters, introverts find them draining.)

She advises me to steer clear of small talk, which is good, because I loathe it. “If you spend the whole week talking about the weather, I think you’ll hate it.” Instead, go deep and be vulnerable. “Share something vulnerable about yourself, even if that seems terrifying. A person will match that normally and you will feel as if you’re making a friend.”

Pan gives me a set of rules: no booze because it makes things easier, no taking a friend along for moral support – “That’s cheating!” – and I must spend an hour and a half at each engagement, minimum. Here goes nothing.

Monday

I start the week by attending an Extinction Rebellion induction meeting. I have toyed with the idea of joining the movement for months, but put it off because none of my friends are members and the thought of going alone frightens me.

In a chilly church hall, I take a seat in a circle of stacking chairs. There is a long pause while I steel myself to turn to the person next to me.

“Hi,” I say. “I’m Sirin.”

I start chatting to Ben, who has just moved into the area. He is a friendly bloke with a deep tan and a placid manner. Remembering Pan’s advice, I offer something vulnerable about myself. “I’ve wanted to come to these meetings for ages, but none of my friends wanted to come with me.” My anxieties tumble out. “Also I eat meat and fly, and I’m worried everyone here would judge me.”

Ben looks at me kindly. After the meeting, he waves at me from the church steps. I’ll be back, I think.

Tuesday

This evening I am playing dodgeball with strangers and all I can think about is how much I don’t want to do it. I was abysmal at team sports at school, and the thought of balls ricocheting around me feels like an anxiety dream. After checking the maximum velocity of a dodgeball (70mph), I panic and call Jacob, the Headshot United team coordinator, for some last-minute reassurance.

“We’re really bad,” Jacob promises. “We’ve lost the last nine games. Besides, you can hide at the back. There will be a few people who wear knee pads and stuff like that – try not to worry about them.”

I catch up with Jacob and his teammate, Ed, for a pre-game drink. “Someone joined us last week and said they didn’t have a good time and wouldn’t be coming back,” says Ed. I gulp.

Jacob senses my anxiety. “If you really are hating it, you don’t have to keep playing,” he says.

We head to a nearby school gym. Playing team sports with strangers was exactly like losing my virginity: not memorably awful, but definitely not good. I cringe every time a ball thuds my way and lack the strength to make my throws clear the other side of the court. Obviously, I get hit on the head. “You took that head shot like an absolute champ,” observes a teammate.

While I didn’t enjoy dodgeball – hated it, if I’m honest – I loved meeting everyone. After the game (we lost), I hit the pub with Jacob and his teammate Will. “You’re not the worst newcomer we’ve ever had,” Jacob says.

He’s definitely lying.

Wednesday

Today I am meeting up with Emma, whom I don’t know. We’re going to a Crossfit class – a famously social workout, where high fives, fist bumps and (God forbid) hugs with sweaty strangers are de rigueur.

Emma introduces me to Rich, the owner of Crossfit Shapesmiths in south London. “I’M SO HAPPY TO MEET YOU,” Rich bellows at me. “COME HERE FOR A HUG. COME HERE!” We hug. “He’s like that with everyone,” Emma says. “He’s just really happy.”

I meet JP, who will be leading the class. The workout flies by. Emma is a sweetheart. “You’re doing great!” she cheers, as I flub my way through some complicated moves involving a kettlebell. “Good pace!”

After the class, JP instructs us – orders, really – to high five. Old Sirin would cringe at this enforced bonhomie, but new Sirin is all high fives. I’m just happy I didn’t get hit in the face.

Thursday

“What is a weed?” asks Cathy, the leader of Waltham Forest’s volunteer gardening group, “It’s a plant in the wrong place.”

The group meets every Thursday morning to tend the grounds behind the William Morris Gallery in east London. Looking round, I can relate. I have never gardened before and most of the people here are regulars. Being a newbie among outsiders, doing something I have never done before – not my favourite thing.

My goodness, they are a friendly bunch. We yank out weeds and fling them into a pile. It is a beautiful morning, crisp and clear. I make friends with Judith, who is retired and lives locally. “It’s difficult, making friends in London,” she says. “It’s not like you can just walk up to people in the street. They’d think you were a nutter.”

After a tea break, I’m promoted to planting. I try not to look at the worms that tumble from my spade. “I just fling the worms away,” says Judith conspiratorially. We tuck the plants into the soil together, like children being put to bed. “You’ll come back, won’t you?” says Judith.

Friday

I’m flagging. Pan warned me I would be tired and she was right. If my life were a night out, right now I would be sitting in the smoking area, begging a friend to fetch my coat. The last thing I want to do is hang out with a stranger.

On Bumble BFF, a friendship app, I start chatting to Radhika, 25, a student from Delhi. We meet up later at an audiovisual exhibition about the natural world. It’s not the most successful meeting. Radhika is lovely, but it’s not the sort of place where you can chat and it’s awkward to be walking in silence with someone you have just met. As a result, Radhika and I never get past first base conversationally, which makes our interaction stilted, like kissing with braces. In the gallery, the sounds of the wilderness are compressed into a bright heartbeat of lasers. Radhika says she was homesick last week – it was the Diwali celebration. A few friends had had a gathering, but it wasn’t the same. I feel guilty for co-opting her into my experiment. Moving to a new place on your own is hard.

A lot of my anxiety around socialising is linked to the fact that I often feel responsible for making conversation, as I do today. The encounter was wearing, probably because I already felt drained. After the exhibition, I suggest a drink, but Radhika declines. I’m relieved.

Saturday

I wake up with a ball of dread in my stomach that won’t go away . Why? I’m going to a Halloween party tonight, full of people I don’t know, and I’ll be flying solo.

As evening approaches, the feeling intensifies. I desperately don’t want to go and find myself tidying drawers and sorting laundry until I can’t put off going any longer.

Outside the house, I text Pan for some last-minute support. “ARGH I DON’T WANT TO GO TO THIS PARTY ON MY OWN.” She texts back. “Talk to three people and if they suck, you can leave. Also, ask the host to introduce you to some people.”

I take a breath and ring the bell.

Ordinarily, the hardest part of going to a party alone is walking in, not knowing anyone. In my case, it was realising once through the door that not only did I not know anyone, they were all in fancy dress. Luckily, the host Dan (not his real name) or, rather, Emperor Caligula – takes me under his wing. He introduces me to Gosia and Ula, sisters from Poland. Pan’s tip to let myself be vulnerable definitely helps: I tell Gosia and Ula about my anxieties and they look after me all evening as carefully as if I were a baby bird.

It’s a great party. There is a severed head in the freezer and drinks are served in IV bags – but I’m so tired after the week’s exertions that I only last a few hours before making my excuses. “Your costume was awful,” Dan says, walking me to the door.

Sunday

I am comfortably the youngest person by a few decades on today’s walk, which is organised by the London Strollers. It’s no bother – one of the joys of my week of extroversion has been the opportunity to chat to older people.

About 30 of us set off on a three-hour walk around north London. Things do not start off well. Although the woman I had been walking with seems friendly initially, she then makes a number of offensive comments. The thought of having to spend the morning listening to her fills me with a crushing ennui. I am already so tired. I don’t think I can bear this.

Then Elizabeth comes to my rescue. She is very tall and upright, a headscarf knotted under her chin – my knight in a green raincoat.

We talk about everything. How she has just got into football and is learning Italian, which will be her sixth language. Her childhood in Finland, and the 40 years she spent as a nurse. (She retired five years ago, at the age of 70.) She tells me about her husband, a communist, who died. And her children, who also died. And why you should only marry someone with the same political views as yours – preferably a communist. “Socialists, they sit on the fence,” Elizabeth shrugs, striding up Primrose Hill.

I loved meeting Elizabeth. I could have talked to her all day. I take her number and we make loose plans to go to a protest together.

It’s all over

So what did I learn from my week of extroversion? That people are kinder than you think and it is often easier to be truthful with strangers. That you should open yourself up to new experiences because the worst that can happen is getting hit in the face with a dodgeball, and that is not so bad. That we are all of us individual moving dots, part of the same involuntary palpitating life, crisscrossing as we walk the streets. It’s nice for the dots to collide sometimes, even for a little while. Strangers can come together and share their stories. We all have a story to tell.

I’m still an introvert and I don’t see that changing soon. But perhaps you will see me a bit more from now on. Maybe.

• This article was amended on 18 November 2019 because an earlier version was wrong to describe the University of California research as “the first study of its kind”. This has been corrected.