A brainstorm or any session where you are either trying to solve a problem through interaction with a group requires two different types of thinking: divergent and convergent.
Divergent vs. convergent thinking
Divergent thinking is about broadening the range of possibilities.
This is the classic brainstorm where you are supposed to list out as many ideas as possible without any judgement.
Divergent thinking like this is exciting and fun.
This is especially true if you are given license to list out any and all wild ideas.
The problem is that at the end of the session, all that you have is a list of possibilities.
Convergent thinking is about narrowing the range of options either by elimination or integration. Convergent thinking is much harder to do because it means you will have to make a decision.
What if you are wrong?
You also have to consider the sensitivities of those who proposed ideas you are dismissing.
Yet convergent thinking is how you get to something actionable.
The problem is we don't often take the time to consider in a given session whether the group is thinking divergently or convergently.
Stuck in divergence
The risk is that you always remain in divergent thinking mode. I see this in group discussions all the time.
You have discussed an issue, had some exciting ideas put on the table, and then out of the blue someone brings up another point that is really not that topical.
If there is a sense that the convergent decision you are about to make is either difficult to make, or that someone in the group won't agree there is more of chance that there will be resistance.
An off-topic idea or comment is a great way to shift away from what you are afraid to discuss. So, others jump onto the tangental topic, and away you go.
This is why often at the end of a meeting or conference call someone says what the action points are and there is silence or "I guess, so and so will do..."
That last gasp decision on what will be done is rapid-fire convergent thinking. It is hardly satisfactory.
Pay attention to how the group is thinking
If you want to have a productive session, you need to know when to be divergent and when to switch to convergent thinking.
You also have to be prepared.
Divergent thinking is more rapid-fire, and people will respond quickly with their own ideas.
Switch to convergent thinking. "How should we decide which is the best?" The pace of the dialogue will slow down.
You have to be comfortable with providing some space to allow the participants to think. This may mean awkward silence.
The key is to make sure you get to convergent thinking as soon as possible, but not too fast.
Making that switch is often necessary because you are running out of time. It is important to make the switch.
When you have a productive round of convergent thinking, the excitement of the group increases.
To do this consistently, it is best to have someone moderating the session who has in mind the need to switch from divergent to convergent thinking.
That does not let other participants off the hook. When everyone understands this dynamic the process if much more efficient.
Understanding the process also will underscore that throughout the session, it is vital for everyone to actively listen and to actively think.
The next time you are in a brainstorm session remember that the trick to making the session productive is to know when to switch from divergent to convergent thinking.