Brainstorming is an idea-generation technique in which a group (or a person) produces as many ideas as possible about a problem, without judging them at the moment of creation. The term was popularized by advertising executive Alex Osborn in his book "Applied Imagination" (1953). The premise is simple: separate the phase of generating ideas from the phase of evaluating them.

What does brainstorming mean?

Brainstorming literally means a "storm of ideas": a session focused on producing many ideas quickly, leaving criticism for later. Alex Osborn created the method after noticing that, in ordinary meetings, the fear of judgment made people self-censor and propose few ideas.

The core idea is that quantity breeds quality: the more ideas on the table, the greater the chance a truly good one will emerge. "Bad" or absurd ideas have value because they can inspire others. That's why, in brainstorming, judging and generating never happen at the same time.

The 4 rules of brainstorming (Osborn)

Osborn defined four rules that make a session effective:

Defer judgment. No idea is criticized during generation. Evaluation comes later.
Go for quantity. The more ideas, the better. The goal is volume.
Welcome bold ideas. Unusual ideas are welcome — it's easier to tame a wild idea than to liven up a timid one.
Combine and improve. Build on others' ideas; mix concepts to create new ones.

Following these rules is what separates a productive brainstorm from an ordinary meeting where a few voices dominate.

How to run a brainstorming session step by step

Define the problem as a clear question (e.g. "How can we improve user retention?").
Gather ideas without filtering — everyone contributes; nothing is discarded at this stage.
Record everything visibly, ideally on a mind map, so ideas connect and spark new ones.
Group by affinity when the flow slows down.
Evaluate and prioritize only at the end, separating the most promising ideas.

Using a mind map in step 3 is especially effective: the problem sits at the center and each idea becomes a branch, which encourages associations and keeps the record organized.

Frequently asked questions

Who invented brainstorming? American advertising executive Alex Osborn, who described the technique in his 1953 book "Applied Imagination".

Can you brainstorm alone? Yes. Individual "brainwriting" — writing ideas without self-censoring — follows the same logic. A mind map helps you explore the topic in every direction.

What's the difference between brainstorming and a mind map? Brainstorming is the process of generating ideas; the mind map is a visual tool to record and connect those ideas. The two work very well together.

Run your brainstorm in InMaps — start from the brainstorming template.