Teaching students how to create and interpret a concept map can often take up two or three lesson plans. Students will not be able to use concept maps effectively if they are only "shown" how to draw the map; they must also be taught how to organize information and ideas, how to interpret these and how to apply this map of ideas to critical thinking. The creation of a concept map is relatively straightforward, but linking it to critical thinking is a process that may take several teaching sessions. Many people consider the teaching of this "quick" concept mapping skill too long-winded to justify the results for a student's critical thinking skills.
Concept maps only contain simple information that the student quickly processes and writes down. There is little for the student to use if they cannot remember why they put a particular idea down on the concept map. If they were drawing a concept map on the subject of animal cruelty, for example, and the student wrote down "money" in an act of quick thinking to get all their ideas down, then there is no guarantee they will be capable of critically evaluating the idea of "money" in relation to the subject. Sometimes, writing down a well-thought-out idea in the form of a few words or phrases is not enough to justify the idea or guarantee accurate retrieval of the student's idea from memory when looking back upon the concept map.
Students, when using a concept map for critical thinking, may not be basing their theories on well-thought-out, evidence-based material when the original idea is lost through the paraphrasing of words. Critical thinking must be carefully calculated and evaluated from well-formed ideas rather than notes in the form of a semi-organized hierarchical diagram.
Concept mapping has often been linked to the idea of "clustering" information, which is used for creative subjects such as creative writing or art. The concept map may claim to produce ideas that are relevant to the subject, but students still must clarify this connection when looking back on the concept map. They may often find they are writing down words, even if they are organized and structured, that are not relevant to the subject matter at all and will spend even more time trying to critically evaluate irrelevant topics. Writing down words or phrases that simply "pop" into the brain is known as "clustering" -- the brain will link words or ideas it familiarizes with the subject matter, but these words or phrases may not be relevant in a critical thinking classroom; they are the brain's interpretation of a concept which it is trying to link together to form something concrete from familiar ideas, thoughts and images.
The concept map is often taught to students at any level of study, but this may only confuse students when it comes to critical thinking tasks. Not only are students required to create a concept map and link abstract ideas together, but they are also required to relate this concept map to critical thinking skills. The concept map is visual in some forms but it still only contains words and abstract ideas; younger students grasp concepts through concrete imagery and, whether or not the concept map is designed in various colors and pictures, the concept map is still little more than a collection of words and abstractions based on an original abstract subject -- there is little progression from the original subject (the "center" of the concept map) to concrete, understandable and well-informed evidence-based ideas. Critical thinking should be encouraged by the use of abstract ideas placed into easier concepts, or concrete images, rather than translated into other ideas and words through the concept map.