Open plan offices are meant to boost teamwork, collaboration and conversation.

However, according to a new study, they do the opposite.

Staff working in an open-plan office have around 70 per cent less physical interactions with other employees, opting to talk over email and instant messaging services instead.

Employees in open-plan offices often feel exposed and vulnerable, and take precautions to look busy, such as staring intently at a screen and avoiding eye contact, according to the study.

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Working in an open-plan office doesn't boost teamwork and productivity, it prevents it, claim two Harvard researchers. Open-plan offices are designed to encourage more face-to-face interactions to increase productivity (stock)

The theory behind open-plan offices is that by removing physical boundaries people will be more inclined to have more discussions, boosting productivity.

But offices without physical boundaries actually have the opposite affect, causing people to withdraw from social situations.

Dr Ethan Bernstein, co-author of the study from Harvard business school, told The Times: 'On the one hand, it is hard to believe that people would not have a more vibrant and interactive experience when they work in an open office.

'The sociology of it is clear: "proximity breeds interaction".

'On the other hand, I've spent enough time on the Tube at rush hour to see that being packed together doesn't necessarily lead to interaction.'

The alternative to an open-plan office is a cubicle-based arrangement, which some people claim deters collaboration.

However, when studying the staff behaviour at two large, Fortune 500 companies, as they made the transition to an open-plan office, the researchers saw this was not the case.

In open-plan offices, physical interactions dropped by 70 per cent.

Before the move, participants accumulated an average of around 5.8 hours of face-to-face interaction per person per day.

This dropped to around 1.7 hours of face-to-face interaction after the switch.

As well as the loss of physically talking, employees took their conversations digital.

In the study, the authors write that in the first workplace 'IM message activity increased by 67 per cent (99 more messages) and words sent by IM increased by 75 per cent (850 more words).

'Thus — to restate more precisely — in boundaryless space, electronic interaction replaced F2F interaction'

The 150 employees involved in the study wore a specially designed device called a sociometric badge (pictured). Microphones, infrared sensors and an accelerator all built in to the small device, worn around the employee's neck. The badges were used for six weeks in total, three weeks before the move and three weeks afterwards

Dr Bernstein said that the lack of personal space and privacy makes people feel exposed and they compensate for this in other ways.

The 150 employees involved in the study wore a specially designed device called a sociometric badge.

These measured where they were standing, whether they were talking and who they were talking to.

A mixture of gadgets made this possible, with microphones, infrared sensors and an accelerator built in to the small device, worn around the employee's neck.

The badges were used for six weeks in total, three weeks before the move and three weeks afterwards.

The results clearly showed that physical communication plummeted and virtual conversations surged.

'Look around open-plan offices and you can see why this might be,' he said.

'People put on huge headphones to avoid distraction. They stare intently at their screens because they know people are watching and want to look busy.

'Then people looking at them from across the room see someone working intently and don't want to interrupt. So they send an email instead.'

The results have just been published in the oldest scholarly journal in the world, Philosophical Transactions of the Royal Society B.