Les Binet and Sarah Carter get a little bit angry about some of the nonsense they hear around them… like the supposed virtues of collective thinking

At a recent brainstorming, discussion turned to promoting a new product. Someone casually mentioned an upcoming big public event. Could we organise some kind of stunt there? The group seized on the comment, and quickly came up with half-a-dozen ideas. It looked like we'd cracked it.

But then someone pointed out there was little overlap between our target audience and the crowd at the event. The timing was wrong too. Suddenly the idea looked stupid. How could we have been so dumb?

Military strategists would recognise this problem – how groups can make reckless decisions by latching on to any proposal for action, rather than thinking more deeply.

But for 20 years, it has become far more fashionable to focus on the strengths of collective thinking than its weaknesses. The big influence, obviously, is the internet, where the success of open-source projects like Linux and Wikipedia convince that crowd-sourcing is the future. Economists praise the efficiency of markets and 'The Wisdom of Crowds'. Co-creation is the order of the day. The ad industry has embraced this enthusiastically. Brainstorming was invented by an adman: 70 years later, we're as addicted to brainstorming as ever, spending increasing time 'sharing', 'huddling' and 'looping in'.

Technology plays a role too. Electronic calendars mean more meetings crammed into each day. Teleconferencing means distance is no object. Smartphones mean everyone is contactable. And agencies have accelerated the trend, removing barriers to shared working. Open-plan offices are de rigeur, and ideas are crowdsourced online. In this brave new world, all work is group work. All problems solved by the 'hive mind'.

But while some collaboration can be fruitful, others are not. Research repeatedly concludes brainstorming is bad at generating ideas. And open-plan offices reduce productivity, especially for creative and analytical work. In fact, most people say they do their best thinking when alone and relaxed (often in the bath or shower). As a result, increasing numbers of us have to escape the office now to get the real work done.

If collective thinking is unproductive, collective decision-making can be downright dangerous. Because groups try to avoid conflict, they tend to suppress dissent and reject 'inconvenient truths'. Social psychologists call this 'groupthink', and blame it for disastrous mistakes such as the Iraq invasion and the sub-prime crisis. Similarly, investment bubbles remind economists that 'herd behaviour' causes crowds to make poor decisions. In all these crises, it was the lone wolves who made the right call, and the group thinkers who got it wrong.

So how can we get the best from our collective intelligence? Predictive markets give us a clue. Research shows that crowds only make accurate judgments when everyone thinks independently. As soon as people start thinking together, their judgment gets clouded. And this is the key to the success of open-source. Linux and Wikipedia were built by people who mostly thought and worked in isolation, but got together afterwards to share and critique each other's ideas.

Creativity, intelligence and innovation are the lifeblood of our business. They all require independent thought. So forget about brainstorming, huddles and endless meetings. We need time and space to think alone. Technology companies are increasingly aware of this. It may surprise you to hear that Google's London office has a proper old-fashioned library for people to work in, with a strict policy of silence. Maybe it's time to celebrate the power of disconnection.