The frame of a problem is the set of assumptions and attitudes with which you approach it. Making assumptions about possible solutions to a problem can limit creativity, causing difficulty. However, these limits can aid problem solving by preventing us from pursuing wild and improbable paths, such as depending on Martians for help in our solution. Overall, though, the limits placed on us by our own rigidity probably prevent us from finding the best solution at least some of the time. Rigidity in framing the problem is called Einstellung.

People tend to regard an object as if it had only one possible function. For example, they look at a saw and see a tool only good for cutting. But, a saw could also be used as, say, a musical instrument! The failure to see other possible uses for an object is called functional fixedness. Try to solve the following problem without looking at the solution below: You are given a candle, a book of matches, and a box of tacks. Your task is to find a way to attach the candle to the wall so that it will burn properly at eye level and light up the room. (Once you have tried to solve this problem, look at the solution below.)

This problem is difficult because people tend to think of the box as only having one function: as a container. It becomes much easier if people are able to escape that functional fixedness and think of the box as a possible platform.

When trying to solve a new problem, people tend to try a few different paths until they find one that works. However, after solving several of the same type of problem, people tend to get stuck in a rut. If the same path works for each problem, people will stop trying new strategies since they have found one that appears to be reliable. This reliance on a single strategy, called strategy rigidity, can be a problem if they encounter a new problem that requires them to use a different method. A problem that might have been easy before, when they were trying several different solutions, now seems impossible, since they are stuck using only one strategy. For example, after solving several complex mathematical problems that require subtraction, a person might have trouble solving a problem that requires addition. He will try again and again to subtract and will keep getting the wrong answer. Although it might be easier to channel out other possible paths if it seems like one is sufficient, this rigidity can seriously limit creativity in problem solving.

People also make assumptions about the problem itself at the very start of the problem-solving process. They assume that some strategies will tend to be useful while others will not. In addition, they may make limiting assumptions about the rules of the problem and about what operators are available to them. As an example, try to solve the Nine Dot Problem, pictured below.

In this problem, the goal is to draw four straight lines, passing through all nine of the dots, without lifting your pencil from the page. You might find it helpful to replicate the dots on a piece of paper for practice. Once you have tried to solve the problem, look at the solution, pictured below.

This problem is difficult on its own, but it is made more difficult by the starting assumptions that people make. They assume that their lines must stay inside the square even though that limitation is not stated anywhere in the problem.