Should Introverts Act Like Extroverts? What Two Decades of Experiments Actually Show

In 2002, William Fleeson, a personality psychologist at Wake Forest University, asked a group of people to carry a handheld device and answer it on a schedule. Every three hours for two weeks, they reported how they had been behaving (talkative or quiet, bold or reserved) and how they felt. Fleeson was testing an idea that sounded almost too neat: that the well-known link between extraversion and happiness, which holds between people, might also hold within a person from hour to hour.

It did. In the paper he published with Adriane Malanos and Noelle Achille in the Journal of Personality and Social Psychology, every single participant was happier in the hours they had acted extraverted than in the hours they had not. Not most participants. All of them, including the ones who scored as introverts on the trait questionnaire. Two further studies in the same paper, one using weekly diaries and one manipulating behaviour in the lab, found the same pattern.

That finding launched a research programme with an awkward implication. If introverts feel better when they act extraverted, should they? Twenty years of experiments later, the answer is more interesting than yes or no, and the disagreement between the studies is where the useful part lives.

What the experiments agree on

Start with the point of consensus, because it is stronger than most people expect.

Fleeson's original work was correlational within person: it showed that hours of sociable behaviour coincided with hours of good mood, but not which caused which. The obvious next step was to assign the behaviour and see what happened. Several teams did.

The largest recent trial came from Seth Margolis and Sonja Lyubomirsky at the University of California, Riverside, published in 2020 in the Journal of Experimental Psychology: General. They recruited 131 adults and ran each through two weeks. In one week, participants were asked to be as talkative, assertive and spontaneous as they could manage. In the other, as deliberate, quiet and reserved as possible. Half did the sociable week first. Each person chose five specific behaviours to change and received reminders. During the extraverted week, positive emotion, feelings of connectedness and flow all rose above baseline; during the introverted week, they fell below it.

A separate line of evidence from Belgium points the same way without any instructions at all. Evy Kuijpers and colleagues at Ghent University and Vrije Universiteit Brussel, publishing in Personality and Social Psychology Bulletin in 2022, followed people with repeated daily surveys and looked at what happened when someone's behaviour drifted above their own trait level. Cumulative positive deviations from a person's usual extraversion were associated with more positive feelings, and cumulative negative deviations with fewer. Behaving more sociably than usual, even unprompted, tracked with feeling better.

So the momentary effect looks real and general. Acting more outgoing lifts mood in the moment, and the lift does not appear to be reserved for people who are already outgoing.

Where they disagree: who pays, and in what currency

The disagreement is about what else happens. And here the two most careful trials come to different conclusions.

In 2019, Rowan Jacques-Hamilton, Jessie Sun and Luke Smillie at the University of Melbourne published a randomised controlled trial in the same journal as Margolis and Lyubomirsky, with a title that announced its intent: Costs and Benefits of Acting Extraverted. They assigned 147 people to a week of acting extraverted or to a sham intervention, an active control that asked participants to change something unrelated, so that any effect of simply following instructions for a week would be cancelled out.

The overall result matched everyone else: positive affect went up, and so, unexpectedly, did feelings of authenticity. But the Melbourne team had measured more than mood. They had tracked negative affect and tiredness, and they had looked at whether the effects depended on where a person started. More introverted participants got a smaller boost in positive affect, reported more negative affect and more tiredness, and felt less authentic during the week. The intervention worked, on average, and it cost the people at the introverted end of the scale something real.

Margolis and Lyubomirsky, a year later, checked for the same moderation and did not find it. In their study, baseline extraversion did not change the outcome. Introverts got the benefit and did not show the cost.

Two well-run trials, similar instructions, opposite answers on the question everyone actually cares about. Neither team fabricated anything. So what differs?

Reading the disagreement

Three design differences seem to matter, and none of them is a technicality.

What the control condition was. The Melbourne trial used a sham intervention. Any effect of being asked to do something and paying attention to yourself for a week was subtracted out, leaving a cleaner estimate of the extraverted behaviour itself, and a cleaner view of its costs. The Riverside trial compared the extraverted week to the introverted week and to baseline. That is a legitimate design, but it means some of the "benefit" of the sociable week may be relief from the reserved week, and it makes costs harder to see.

What was measured. The Melbourne team measured tiredness and authenticity alongside mood. The Riverside team measured positive and negative emotion, connectedness and flow, but not tiredness or authenticity. A cost that is not measured cannot be found. If introverts pay for a sociable week mainly in fatigue and a sense of being fake rather than in worse mood, a study that tracks mood alone will report no cost, correctly, and miss the bill.

How the behaviour was chosen. Margolis and Lyubomirsky had each participant pick their own five behaviour changes. That is a subtle but potentially large difference. An introvert who chooses "say hello to a colleague each morning" and "ask one question in meetings" is acting extraverted on their own terms. An introvert told to be "as talkative, bold and assertive as possible" for seven days is being asked to run at someone else's pace. It would not be surprising if the second produced fatigue and the first did not.

Put those together and the two trials stop looking contradictory. They look like two doses of the same treatment. Both raise mood. The higher, less chosen, more sustained dose also produces side effects, and the side effects concentrate in the people whose baseline is furthest from the target.

The part the introverts get wrong

There is a third finding that changes how all of this should be read, and it comes from before either trial.

In 2013, John Zelenski and colleagues at Carleton University asked a simple question: do introverts know that acting extraverted would feel fine? In a series of studies in the Journal of Personality and Social Psychology, they had people forecast how they would feel behaving in outgoing ways across a range of situations, then had them actually do it. Introverts predicted less pleasure and more discomfort than they went on to experience, and the error was concentrated on the negative side: they overestimated how anxious and self-conscious they would feel, more than they underestimated the enjoyment.

Zelenski's lab has since summarised the programme in plain terms on its own site: the answer to "should introverts act more extraverted?" is probably "a bit more than they currently do," with the emphasis on their own forecasts rather than on any personality overhaul.

That finding sits in a particular relation to the cost debate. The Melbourne trial says a week of forced sociability tires introverts. The Carleton studies say introverts expect a single sociable episode to be worse than it is. Both can be true. An introvert can be right that a sustained, imposed extraverted week would exhaust them and wrong that the coffee on Thursday would.

What this does not tell us

Several things, and the honest version of this article has to say them.

All of these trials are short. One week, two weeks. Nobody has run a six-month study of acting extraverted, so the long-run picture, and in particular whether costs accumulate or adapt, is unknown. The samples are mostly students or online adults in wealthy countries, and none of the trials was designed around lonely people specifically, which is the population most likely to be told to "get out more."

The mechanism is also unresolved. Margolis and Lyubomirsky could not say which of talkativeness, assertiveness or spontaneity was doing the work. It is possible that the entire effect comes from social contact and has nothing to do with "extraversion" as a trait, in which case the question in this article's title is the wrong question.

And there is a measurement problem lurking under the whole literature. "Acting extraverted" was operationalised differently in every study. Fleeson's participants rated their own behaviour. The trials issued instructions. Kuijpers measured drift from a baseline. Whether these are the same thing is not obvious, and the Kuijpers group has since published work asking whether different ways of measuring deviation from a person's usual extraversion even produce the same affective results.

Synthesis: the dose, not the diagnosis

If you hold the whole literature at once, a reasonably consistent picture appears, and it is not the one either camp usually leads with.

Acting more sociably raises positive affect in the moment, for nearly everyone, including introverts. That is the most replicated result here. Sustained, imposed sociability at a high intensity produces costs, and the costs fall hardest on the people whose baseline is lowest. That result comes from the trial with the cleanest control and the widest set of outcome measures, so it should be taken seriously. And introverts systematically over-forecast the cost of small doses, which means they under-consume the thing that would help.

The practical reading, then, is about dose and choice rather than about personality. Brief, chosen, bounded episodes of sociability, the kind Margolis and Lyubomirsky's participants selected for themselves, appear to deliver the benefit without the bill. A week of running at an extrovert's pace does not. The question "should introverts act like extroverts" dissolves into a better one: how much sociable behaviour, chosen how, delivers the mood benefit before the fatigue arrives? The trials suggest the answer is "more than introverts predict, and less than the instructions in a one-week intervention."

This matters for loneliness because so much advice to lonely people amounts to "be more extraverted," delivered without any dose. We have written before about why more socialising does not always help, and about the outsized value of small, low-stakes interactions. The acting-extraverted literature adds a piece both of those were missing: the barrier for a lonely introvert is often not capacity but forecast. They can do the coffee. They believe they cannot.

A closing thought

The most interesting number in this whole literature is not an effect size. It is the finding, repeated across studies, that the people who most need to know how sociable behaviour would feel are the ones whose predictions are least reliable. That points toward interventions built around lowering the size of the first step until the forecast no longer fires, rather than around persuading anyone to become a different kind of person. Platforms that structure contact into small, bounded, chosen episodes, YaraCircle among them, are one attempt to build on that idea; the evidence reviewed in what actually works to reduce loneliness suggests structure of that kind tends to outperform exhortation.

Fleeson's participants, back in 2002, were happier in their extraverted hours. Twenty years on, the more precise finding is that the hours matter and the weeks may not, and that the introvert deciding whether to go is usually wrong about the hour and right about the week.