Divergent thinking has long been associated with creativity. It is not by itself creativity, but it is a crucial component. It is about generating options, not answering questions. It is about exploring the unfamiliar and pushing to find novelty. Brainstorming is about using divergent thinking in a group. Divergent thinking applies more broadly to a group or an individual.
Convergent thinking is about selecting from those options the one that seems best for the situation. A formal process involves having criteria and evaluating options according to the criteria. On a multiple-choice test, it’s choosing the correct answer, which might involve a process of elimination. In a more open-ended situation, like coming up with a winning science fair project, you would probably consider what the judges will appreciate as well as your strengths and your interests--although before that you might use divergent thinking to answer the questions, “What are all the possible topics I could do for the science fair?”.
So as you can see, divergent thinking (DT) and convergent thinking (CT) are a pair. First, come up with a list of science fair projects, then select the best one for the situation. However, it is important to separate these two steps. To grow the list of options for the science fair, you don’t want to stop and evaluate after each option is thought of. It’s almost impossible to get a lot of ideas this way! Linus Pauling, the winner of two Nobel prizes, has stated that the best way to come up with a good idea is to come up with a lot of ideas. (Research backs this up!) The good idea will come from the many! So diverge first, converge afterward.
The best way to stay in the DT mode and avoid evaluating too soon is to practice something called deferring judgment. That means to put off judgment till later--although not forever. Let’s say you want to brainstorm with your teammates. To do it well, you all have to get into the no-judgment zone. You say “yes” to every idea and option that you think of and that someone else shares. Saying yes doesn’t mean you love it and will use it, it means you acknowledge it and welcome it into the pool of ideas. In this way, people will continue to offer ideas, build off each other’s ideas, combine them and maybe even get a little goofy. This is all good! Being playful helps people be less critical. Humor invites unusual connections. From that, you may find the wonderful idea you hoped for.