A CONCEPT IS A SET OF OBJECTS OR EVENTS that share common characteristics and a common name. Clark recommends that conceptual instruction should be structured around four elements: definition, example, non-example, and analogy (Clark, 1999). That is, when teaching concepts always provide a definition and examples of the concept. If possible, also provide non-examples and analogies.

A definition is a statement of the critical features associated with the concept (Clark, 1999). It may not be easy to give a good definition, especially when the technical specialist is so familiar with the concept that he or she has to really consider the key features. For example, the definition of "chair" might be "a piece of furniture with a seat for one person and a back." Based on this definition you can tell that furniture with more than one seat shouldn't be called a "chair". 

Chair    

    Folding Chair                                                Office Chair                                                      Dining Chair

Non-chair

                                       Sofa                                                                                          Couch

An example is a real instance of the concept (Clark, 1999). After presenting the definition, the concept will become more concrete by presenting examples. A good example will visualize the definition by presenting the features of the concept. On the contrary, a non-example is an instance of a closely related concept that could be confused with the lesson concept. When the learners can tell the difference between example and non-example, they understand the concept.

It is significant to choose a range of example and non-example. In the following picture, the cat and the chair are non-example of the concept "dog.". The cat will be more helpful to use than the chair since, except for the four legs, the concept of the chair and the dog share no common features. A good non-example is a concept whose features partly overlap those of the example, and could potentially be confused with the example of the concept. 

An analogy is a representation that corresponds with a concept in function or form but which is other wise dissimilar (Clark, 1999). For example, when teaching fractions, the image of dividing a pie can be used to analogize the concept. The teacher usually shows how the pie can be cut into halves, then quarters, and so on. An effective analogy will be something familiar to the learners that precisely exhibit critical functions or features of the target concept.

When teaching a concept, the instructor should present the definition, an example, a non-example, and an analogy of the concept tp help learners understand the concept.

Tina I- Jou Chen
SDSU Educational Technology
Graduate Student