Einstellung () is the development of a mechanized state of mind. Often called a problem solving set, Einstellung refers to a person's predisposition to solve a given problem in a specific manner even though better or more appropriate methods of solving the problem exist. The Einstellung effect is the negative effect of previous experience when solving new problems. The Einstellung effect has been tested experimentally in many different contexts. The most famous example (which led to the coining of the term by Abraham S. Luchins and Edith Hirsch Luchins) is the Luchins water jar experiment, in which subjects were asked to solve a series of water jar problems. After solving many problems which had the same solution, subjects applied the same solution to later problems even though a simpler solution existed (Luchins, 1942). Other experiments on the Einstellung effect can be found in The Effect of Einstellung on Compositional Processes and Rigidity of Behavior, A Variational Approach to the Effect of Einstellung. Background Einstellung literally means "setting" or "installation" as well as a person's "attitude" in German. Related to Einstellung is what is referred to as an Aufgabe ("task" in German). The Aufgabe is the situation which could potentially invoke the Einstellung effect. It is a task which creates a tendency to execute a previously applicable behavior. In the Luchins and Luchins experiment a water jar problem served as the Aufgabe, or task. The Einstellung effect occurs when a person is presented with a problem or situation that is similar to problems they have worked through in the past. If the solution (or appropriate behavior) to the problem/situation has been the same in each past experience, the person will likely provide that same response, without giving the problem too much thought, even though a more appropriate response might be available. Essentially, the Einstellung effect is one of the human brain's ways of finding an appropriate solution/behavior as efficiently as possible. The detail is that though finding the solution is efficient, the solution itself is not or might not be. Another phenomenon similar to Einstellung is functional fixedness (Duncker 1945). Functional fixedness is an impaired ability to discover a new use for an object, owing to the subject's previous use of the object in a functionally dissimilar context. It can also be deemed a cognitive bias that limits a person to using an object only in the way it is traditionally