Brainstorming is a very specific way of thinking as a group. Generally you brainstorm at the beginning of a project or when there’s a collective problem that needs solving. It’s very much an early part of the ideas process and involves a group of people throwing out as many ideas as possible. The idea is not to arrive at the answer, but to create options for working towards it. So it’s just stage one in the project.

In some ways it’s seen as the classic style of group thinking. It was first formulated as a technique back in the 1930s by Alex F. Osborn, although one imagines people must have been doing something similar for millennia before he refined the process. Osborn had become frustrated by how few ideas his staff came up with (he was an advertising executive) so he began setting them to think in teams.

However he recognised the inherent problems in simply putting several people in a room and telling them to shout out ideas, so he came up with rules or guidelines to make the process work better. These work because they’re based on an empirical understanding of how people think best.

Osborn established that a group will brainstorm most effectively if you set only one problem to address, and make it clear and specific before the session starts. So for example, rather than brainstorm how to sell a new product, it is more effective to brainstorm specifically how to generate sales leads or where to advertise. This means you can focus your thinking on the issue and not get bogged down in what the question means.

The aim of the exercise is to come up with as many ideas as possible to give the maximum range to choose from. We know that more ideas equal more good ideas, so quantity is paramount.

In order to get the maximum number of ideas, one of the principles is that extreme or wild ideas are actively encouraged. This is a group exercise, and even if an idea isn’t workable in itself it doesn’t matter because it may stimulate another idea that is. So at this stage you’re not looking for workable ideas, you’re just looking for lots of ideas.

My favourite of Osborn’s principles is that no one is allowed to offer criticism, judgement, disagreement or negative comment on any ideas. That comes later (if at all). This is hugely important because without this rule group members are inclined to self-censor to avoid having their ideas judged. If you know you won’t be criticised, you’ll be much more willing to throw out whatever ideas come into your head.

The overall effect of a brainstorming session is to stimulate everyone’s creative thinking process so you generate plenty of ideas in a ‘safe’ environment and can also build on and spark off each other’s suggestions.

Over the decades people have come up with lots of individual strategies and techniques for running brainstorming sessions. Some of them are excellent and you can research and use them if you like. However you don’t need to go beyond Osborn’s original rules to stimulate creative and productive thinking among a group of people.