Anchoring  -  When a person is provided with a possible answer and then is asked to provide her own answer, her response tends to be close to the provided estimate, because the availability of that estimate is high.

Atypical  -  Atypical means different from others in the group.

Availability  -  Items that are more "available" in memory are more easily recalled. People tend to base their answers on whatever springs to mind the easiest, rather than on true statistical frequency.

Bias  -  Irrelevant or flawed information that nevertheless influences judgment.

Chunking  -  Chunking is a method of organizing information by grouping items together in a meaningful way. Chunking, used often by experts, can aid memory and problem-solving.

Einstellung  -  Einstellung refers to a rigid way of framing a problem, causing resistance to creativity.

Expert  -  A person with ten or more years of experience solving problems in a particular field is considered an expert in that field.

Frame  -  The frame of a problem depends on how we view it. It refers to the assumptions that we bring to bear when approaching a problem.

Generalize  -  To generalize is to assume that one individual is an accurate representation of an entire group. For example, if I know that my thirteen-year-old sister loves Britney Spears, I would be generalizing if I assumed that all thirteen-year-old girls love Britney Spears.

Goal State  -  The ending point of a problem; the solution you want to reach.

Heuristics  -  Shortcuts in reasoning that allow us to make judgments with little time or evidence.

Infer  -  To infer is to make a logical guess based on available information.

Initial State  -  The starting point of a problem; the materials and knowledge you have at the beginning.

Novice  -  A person with little or no experience in a particular field is considered a novice in that field. Novices generally solve problems less efficiently than experts.

Path Constraints  -  Path constraints limit the number of choices possible at a given point in the problem space.

Problem Space  -  All the possible ways to reach the goal state from the initial state.

Reasoning by Analogy  -  Reasoning by analogy is a problem-solving method in which knowledge of previous problems with similar structures is used to find the best way to solve the current problem.

Representative  -  To say that a thing is representative of a group is to say that it is the same as the average of the entire group. For example, if librarians in general tend to be stern old women, and the librarian in my town is a stern old woman, then I would say that my librarian is representative of librarians as a group.

Subgoal  -  Most large problems can be broken down into a series of smaller subproblems. Each smaller problem has its own goal, called a subgoal.

Subproblem  -  Most large problems can be broken down into a series of smaller subproblems. Subproblems have their own initial states, goal states, and operators. People tend to work slowly when deciding how to break down a complex problem, but quickly when solving subproblems.

Answer to the Water Lilies Problem  -  The Water Lilies Problem is best solved by working backward from the last day. The solution is the eighty-ninth day.