 Blackmore notes that human brains began expanding in size at about the same time that we started using tools and suggests that once individuals began to imitate each other, selection pressure favored those who could make good choices on what to imitate, and could imitate intelligently.In the book, Blackmore tries to create a consistent vocabulary, since memetics has had a wide range of different terminologies and therefore, in Blackmore's opinion, many misleading concepts.Some of the terms that are central in her book include