Science has proved what theatre and concert-goers have long known. When it comes to emotional impact, watching a live performance is so much more thrilling than a version on screen.

Scientists from University College London (UCL) measured heart rates and sweat glands of audience members as they watched both theatre productions and films. They found that heart rates go up and down with the narrative arc of a story and that the highs are highest and lows lowest at a live show. Heart rate levels changed approximately twice as much among those watching live theatre than in people viewing a film.

Joseph Devlin, professor of cognitive neuroscience at UCL, told the Guardian: “A big part of the live performance is that we are fundamentally a social species. Any time you go to a live performance, whether it’s a concert or a show, people often talk about the energy or the buzz of it. Everyone knows what you’re talking about, but what is it exactly?

“What we have found is that part of it is people’s hearts starting to synchronise within the group, and you feed off the response of the people around you. You hear their emotional responses, their gasps, their claps, their laughs, or their horror, depending on what it is you’re watching. You mirror that in yourself and that amplifies your own personal experience.”

He added: “It’s really remarkable but, when you have that shared experience that’s being driven by a particular performance, you start to see people’s heart rates go in and out of synchrony with each other, particularly in more emotionally compelling areas.”

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The UCL study compared the responses of audiences to Dreamgirls, an award-winning stage musical, and the film adaptation, which was “really close to the theatre version, so you’re comparing apples and apples”, Devlin said.

Dreamgirls is about a fictional 1960s girl group, the Dreams, and their rise from Detroit talent shows to platinum-selling superstars. Loosely inspired by Diana Ross and the Supremes, its West End premiere came about 35 years after it became a multi-award-winning Broadway smash.

Devlin said the fact that the variance in heart rates was largest in the theatre audience and lowest in the individuals watching the movie was consistent with the idea of “emotional amplification”. “Being at a live show in a big audience generates a lot of energy and people respond more strongly to the show in those circumstances, feeding off the energy of the performance and the crowd. This leads to greater audience engagement and produces the higher highs and the lower lows,” he said.

“The same effect is present when watching a movie with an audience, but to a small degree. That is, one’s excitement or engagement is still enhanced by the presence of others but, by virtue of a smaller crowd, this is reduced relative to a big West End theatre audience. It’s still more engaging, though, than watching the same video on your own.”

Almost 70 people between the ages of 18 and 65 took part in the UCL study. They wore an Empatica E4 wristband, a medical-grade device that measures heart rates and electrodermal activity.

Devlin said: “Your sweat glands, that’s what it’s literally measuring, the conductance on your skin, which is affected by really small changes in perspiration. It’s remarkably sensitive to your emotional state … It cannot tell positive from negative emotions – elation from fear, for instance – but it can measure overall emotional arousal levels.”

The scientists also found that the size of the audience had an impact on emotional responses. Devlin said: “In the Savoy [theatre], the seating is for about 1,100 people. Even big cinemas probably have only 100 to 200 people. The size of the audience seems to matter.”

While data analysis continues, further experiments will follow. Devlin sees the potential for using such technology one day to shape productions according to what gets heart rates going. It could even be used in political rallies, he suggests.

The research followed a 2017 study in which UCL measured audience reactions to the Dreamgirls production at the Savoy theatre and found that watching live theatre can stimulate the cardiovascular system as much as doing 28 minutes of healthy cardio exercise.