# Production blocking
Production blocking is the tendency for one individual to block other people during a group discussion. In a group of five people, for example, when one person is talking about their ideas, the other four people are blocked. The four people will have to listen to the one person talking, therefore they will not be able to come up with new ideas, or they would merely forget about their ideas. If the five people are able to communicate their ideas at the same time, ironically that may indicate that the group members haven't been listening to each other (a different form of production blocking).
Production blocking is one of the reason why a brainstorming session, especially the interactive ones, might produce less creative ideas. To make a brainstorming session generate more ideas, thoughts must be able to be shared without an interaction with other group members. This would normally come in a form of writing.
Ahrens, How to Take Smart Notes (p. 134).
And before you now wonder if it would be a good idea to overcome the limitations of brainstorming by assembling a group of friends to brainstorm together, forget it: More people in a brainstorming group usually come up with less good ideas and restrict themselves inadvertently to a narrower range of topics (Mullen, Johnson, and Salas 1991).
Footnote: You can avoid that, though, by letting all members brainstorm for themselves and compiling the results afterwards.
Generally people in interactive, brainstorming groups produce fewer ideas and ones that are less creative than those same people would if they were working individually, in what is known as nominal groups. Production blocking, the tendency for one individual during a group discussion to block or inhibit other people from offering ideas, is a major reason.