A concept is the way in which a category or class of objects is represented mentally. Concepts allow individuals to discern class membership or non-membership, relate different classes of objects, and provide context for learning new information about classes and class membership. There is wide debate about the way in which categories and classes are mentally represented and defined. The way in which concepts are learned can depend on the age of the learner, whether or not explicit instructions are provided, and the type of category or class the concept represents.


Concepts can be learned about categories that include people, events, objects, or even ideas. Various divisions have been made between different types of concepts. Concepts can be divided into groups based on the con-creteness of the items involved. Concrete concepts have aspects or dimensions that are easily seen, heard, or touched. Examples of concrete concepts include fruit, dogs, and houses. Concepts can also be categorized as semi-concrete. Semi-concrete concepts are those which are have roughly equal aspects that are concrete and not concrete. An example of a semi-concrete concept is a firefighter. The concept firefighter is defined along some concrete terms, such as wears a fire hat, and along some less concrete terms such as risks his or her life, and protects the public. Concepts that are not easily comprehended with the senses are abstract concepts. Abstract concepts include justice, freedom, and love. These concepts are often the most difficult to explain and have the most complex rules or explanations for determination. Abstract concepts are often very difficult for younger children, and as development progresses, increasingly complex abstract concepts are mastered.

Other differentiations can also be made between different types of concepts. Some concepts are natural concepts. Natural concepts are those that occur in the environment naturally without human intervention. This type of concept includes water, eggs, and monkeys.


There are many different theories about how concepts are learned, what information people have when they have mastered a concept, and how information about new items is related to previously learned concepts.

The Classical View. The classical view of concepts is based on the idea that concepts are defined by lists of rules. It is the first view on record about the idea of concepts, and dates back to Aristotle (384–322 BCE). Each concept is believed to be defined by a list of relevant rules or characteristics, all of which are necessary for the object or instance to be a member of that category or class. For instance, the concept “mug,” includes the rule “is able to hold water,” meaning that a mug must necessarily be able to hold water in order or be classified as a mug. All of the rules taken together that govern a category are sufficient to make something identifiable as a member of that category or class.

The view of concepts as defined by relevant necessary characteristics was the main basis for thought and research about categorization and category learning until the 1950s. At that time, cognitive psychologists and philosophers began to question whether it was a good representation of the way people actually think about categories, especially when they are using them to make judgments in daily life. In the 1970s a series of studies was done, many by Eleanor Rosch, that demonstrated that people did not hold lists of attributes when deciding category membership. Instead, she found that individuals had a mental picture or belief about what made up an example of a member of a class, not a list of well-defined rules (Rosch & Mervis 1975).

Prototype Theory. The prototype idea of concept learning was built on the research done by Rosch and her colleagues. Central to this idea is the concept of a prototype that exists as the ideal example of each category or class for which a concept has been learned. A prototype is an object or item that is the most typical of that concept. There is some debate about whether the prototype is a real example that has been seen or experienced, or it if is an amalgamation of various examples of the concept. If it is an abstract amalgamation it can actually be seen as being more typical of a concept than any actual instance of that concept could be. To determine category membership or non-membership of novel items, each new item is compared with the prototype and the degree of similarity reviewed. Proponents of the prototype theory also often believe that information about examples are organized as being more or less similar to the prototype.

A fairly broad body of evidence developed in the 1970s and afterward in support of the prototype theory. Studies found that participants responded faster to questions about category membership when the item in question was a more typical member of the category than when it was not (McCloskey & Glucksberg, 1979). For example, participants would have responded more quickly to the question, “Is an oak a tree?” than to the question, “Is a bonsai a tree?” Although the developing evidence supported the prototype theory much more strongly than the classical theory, some problems with prototype theory became apparent. Researchers began to find that participants judged items to be more typical of a category in some situations than in others, which prototype theory had difficulty explaining. Also, prototype theory did not explain cases in which an item was very typical of a certain category but was identified as a member of a different category of which it was less typical. For example, although cottage cheese is more typical of pudding than cheese, it is clearly categorized as a cheese.

Exemplar Theory. The exemplar theory of concept learning states that specific examples of concepts are learned, instead of a generalized or prototypical example or a list of specific required characteristics. Proponents of this view believe that although not every example that an individual comes across is stored in the memory, many examples are retained. In this way novel items or circumstances can be compared to examples that are stored in the memory. Novel items that are not similar to any of the stored exemplars are therefore very difficult for people to put into any specific category. Some people believe that the more typical of a category a specific example is, the more likely it is to be stored as an exemplar of that category.

The exemplar view explains many of the results found during research on concept learning and categorization. As discussed above, participants tend to respond more quickly when asked about the category membership of items that are typical of the category in question. This is because these items are more likely to be stored exemplars or more similar to stored exemplars. The exemplar theory also has problems explaining some things. It is not clear how many exemplars are stored or how the determination of storage is made. Another objection frequently raised is that it requires that individuals store many different exemplars for each concept, taking up vast quantities of long-term memory, more so than a single prototype would require.


Views on how people acquire concepts are guided in large part by which theory of concept determination is believed. Research on acquisition of concepts is often seemingly contradictory because individuals use different types of strategies depending on the situation, the type of information involved, and any beliefs about what the structure of the underlying concept is. Concept acquisition is probably a complex process with a number of strategies available depending on the perceived situation.

When individuals are trying to form a concept, and feedback is given about group membership or non-membership, the individuals tend to form and test hypotheses. J. S. Bruner and his colleagues did significant work on this in 1956, examining the way that participants tried to identify a concept provided by the researchers. The participants chose cards and were told whether each card chosen was a member of the group or not. All the participants formed hypotheses and then tested them, but the strategy to achieve this differed across participants. Some participants picked a card that was a member of the group and then tested cards that differed by it in only one respect to determine which aspects of the cards were critical and which were not. Other participants created complex hypotheses and then chose cards that would test the most attributes at once. A third set of participants formed a number of hypotheses but tested them one at a time (Bruner et al., 1956).

Although the above strategies may work when individuals are given feedback about each successive item, this is not particularly likely to occur in day-to-day life. Instead, other strategies for concept acquisition must be used. When individuals have to determine two categories and then assign novel items to one category or the other, different strategies may be used. According to the classical theory, individuals would create a set of rules for each category that were necessary and sufficient for group membership and then apply those rules to each new item. According to the prototype theory, individuals would form a prototype for each category by examining as many of the example items as possible, and then classify novel examples by comparing them to the two prototypes and determining similarity. According to the exemplar theory, examples from each of the two categories would be memorized, and then novel items would be compared to the memorized exemplars for similarity.

The research indicates that individuals use a variety of these approaches, and that no one approach is completely correct. It appears that the various approaches serve different functions, and may be found to be more effective in different situations. Students use a variety of these techniques as different educational concepts are learned. In some cases the expectation of concept formation is made clear and regular feedback is received, in which case the student may be more likely to use hypothesis generation and testing. In other cases the formation of a prototype may appear to be the most effective method for concept attainment. In some cases, especially when the criteria are dictated by the educator, the classical view may be used. In some cases, especially if the student is not completely clear on the underlying concept, exemplars may be memorized to aide in class membership determination.


There are many different ways in which concepts can be taught, and there is some debate about which methods are the most effective. In general, methods differ depending on the desired outcome of the educational experience, the age of the learner, and the difficulty or abstractness of the concept being taught.

The most basic way of teaching concepts is by determining a rule or set of rules for the concept and having the students memorize them. The students can then apply the memorized rule or rules when prompted to make decisions about class membership of novel items. Although this does achieve some objectives of concept learning (i.e., allowing the student to make judgments about class membership), it does not necessarily provide a solid foundation for comparing the concept to previously learned concepts, a basis for learning new concepts, or a strong likelihood that the rule will be applied in novel situations when the student is not prompted.

To provide students with a more solid understanding of the concept, additional information is often useful. Students can be provided with items that are similar to the concept but that differ on one or more dimensions, making them non-members of the category in question. For example, the concept “peninsula” may be defined as “a body of land surrounded by water on three sides.” Relevant examples, such as Florida, may be shown to help give the concept a visual dimension. To achieve more complete student mastery of the concept, students and the educator can discuss what makes other similar items non-members of the class. For example, an island is not a peninsula because it is completely surrounded by water instead of only on three sides. Students can also be shown members of the concept that differ significantly but are still category members, such as the Korean peninsula and a small, local peninsula. Although Florida, the Korean peninsula, and small local peninsulas differ drastically in size and location, they are all members of the category “peninsula.” This can help students create a rich and complex understanding of the concept being studied.

An alternative to teaching concepts through memorization of rules provided by the educator is a more student-centered, hands-on approach. This approach may be more helpful when teaching concepts that do not have simple definitions to older students with more advanced critical thinking skills. Having students decide on the defining characteristics or most ideal examples of a class or category can provide an understanding of a concept deeper than that provided by memorization. Students may be provided with a number of examples of members of a category or class and then be prompted to vocalize their reasoning in categorizing those examples. For more abstract concepts, such as “justice,” or “freedom,” students can be prompted to think critically and debate between themselves why some examples are members of the class when other seemingly similar examples are not. Additionally, the teacher may provide new examples, and the students can discuss where they believe the examples fit, and why they classify them in that way.


Many concepts are a challenge to learn, and are learned slowly as more examples and rules are integrated and information is sorted into more straightforward units. All students learn concepts at different rates, and a student who demonstrates mastery of one concept very quickly may find another particularly challenging. However, some students have more than the expected amount of difficulty learning concepts. Students with learning disabilities often have an especially difficult time learning concepts. Although the degree of difficulty and the types of concepts that commonly present problems differ depending on the learning disability, the degree of disability, and the individual child, some problems are common. Basic math concepts, time concepts including time sequencing, and reading concepts are especially likely to present significant challenges. Students with such problems learning concepts may benefit from additional educational strategies to help prevent the student falling behind as additional information and concepts are built upon concepts that were not completely mastered.

Children and adolescents often bring a lot of information into the classroom. Unfortunately, information gathered through life and experiences outside the classroom is not always completely accurate. Many children have previously conceived notions of concepts before being exposed to them in a classroom setting. When mastering a concept in the classroom involves conceptual change, that is replacing a previously held concept with a new one, students can encounter unexpected difficulties. It is important to identify situations in which previously held concepts are at conflict with the concept being taught, because different educational strategies may be appropriate.

Much of the literature about the difficulties encountered in conceptual change has involved the sciences. This is because students often have ideas about natural phenomena, such as what causes rain, and why it is dark at night, before learning about them in school. In these situations educator-led investigation and discussion may not be the most effective road to concept learning. This is because it may be difficult for students who believe they understand something to think outside that understanding or to accept different ideas presented by other students. In this case, teacher-provided rules and critical criteria can help a student overcome a previously believed, but incorrect, concept. Teaching conceptual change can also be accomplished by discussing student preconceptions about a concept, discussing evidence contrary to the preconceived concept, and guiding the student through a changing understanding to mastery of the correct concept.


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