The theory was proposed in the context of debates about the concept of intelligence, and whether methods which claim to measure intelligence (or aspects thereof) are truly scientific. Gardner's theory argues that intelligence, as it is traditionally defined, does not adequately encompass the wide variety of abilities humans display. In his conception, a child who masters the multiplication table easily is not necessarily more intelligent overall than a child who struggles to do so. The second child may be stronger in another kind of intelligence, and therefore may best learn the given material through a different approach, may excel in a field outside of mathematics, or may even be looking through the multiplication learning process at a fundamentally deeper level that hides a potentially higher mathematical intelligence than in the one who memorizes the concept easily. The theory suggests that, rather than relying on a uniform curriculum, schools should offer "individual-centered education", with curriculum tailored to the needs of each child. (This includes working to help students develop the intelligences in which they are weaker.) Gardner identifies kinds of intelligences based upon eight criteria. His eight criteria for describing something as an independent kind of intelligence (rather than merely one of the skills or abilities included in a kind of intelligence, or a synonym for, or combination of other kinds of intelligence) include:
Gardner originally identified seven core intelligences: linguistic, logical-mathematical, spatial, bodily-kinesthetic, musical, interpersonal and intrapersonal. In 1999 he added an eighth, the naturalistic intelligence, and indicated that investigation continues on whether there is an existential intelligence.
The theory has been widely criticized in the psychology and educational theory communities. The most common criticisms argue that Gardner's theory is based on his own intuition rather than empirical data and that the intelligences are just other names for talents or personality types. Despite these criticisms, the theory has enjoyed a great deal of popularity amongst educators over the past twenty years. There are several schools which espouse MI as a pedagogy, and many individual teachers who incorporate some or all of the theory into their methodology. Many books and educational materials exist which explain the theory and how it may be applied to the classroom.
Careers which suit those with this intelligence include politicians, managers, teachers, social workers and diplomats.
Careers which suit those with this intelligence include writers, lawyers, philosophers, journalists, politicians and teachers.
Those who automatically correlate this intelligence with skill in mathematics criticize this intelligence by arguing that logical ability is often more strongly correlated with verbal rather than mathematical ability: for example, in the Graduate Record Examination, a test often used in the United States to decide who will be admitted to graduate school, the old Analytic section correlated more strongly with the Verbal section than the Mathematical. One possibility is that formal, symbolic logic and strict logic games are under the command of mathematical intelligence, while skills such as fallacy hunting, argument construction, etc. are under the command of verbal intelligence.
Careers which suit those with this intelligence include scientists, mathematicians, engineers, doctors and economists.
The theory behind this intelligence is often criticized, much like the spiritual or existential intelligence (see below), as it is seen by many as not indicative of an intelligence but rather an interest. However it might have been a more valuable and useful intelligence in prehistoric times when humans lived closer to nature.
Careers which suit those with this intelligence include scientists, naturalists, conservationists, gardeners and farmers.
Careers which suit those with this intelligence include philosophers, psychologists, theologians, writers and scientists.
This area has to do with vision and spatial judgment. People with strong visual-spatial intelligence are typically very good at visualizing and mentally manipulating objects. They have a strong visual memory and are often artistically inclined. Those with visual-spatial intelligence also generally have a very good sense of direction and may also have very good hand-eye coordination, although this is normally seen as a characteristic of the bodily-kinesthetic intelligence.
Some critics point out the high correlation between the spatial and mathematical abilities, which seems to disprove the clear separation of the intelligences as Gardner theorized. Since solving a mathematical problem involves reasoningly manipulating symbols and numbers, spatial intelligence is involved in visually changing the reality. A thorough understanding of the two intelligences precludes this criticism, however, as the two intelligences do not precisely conform to the definitions of visual and mathematical abilities. Although they may share certain characteristics, they are easily distinguished by several factors, and there are many with strong logical-mathematical intelligence and weak visual-spatial, and vice versa.
This area has to do with rhythm, music, and hearing. Those who have a high level of musical-rhythmic intelligence display greater sensitivity to sounds, rhythms, tones, and music. They normally have good pitch and may even have absolute pitch, and are able to sing, play musical instruments, and compose music. Since there is a strong auditory component to this intelligence, those who are strongest in it may learn best via lecture. In addition, they will often use songs or rhythms to learn and memorize information, and may work best with music playing in the background.
Careers which suit those with this intelligence include instrumentalists, singers, conductors, disc-jockeys, and composers.
Gardner used case studies of Autistic Savants as part of his theory on multiple intelligences. On one hand they have severe mental disabilities and thus impaired social skills, on the other they have some extraordinary mental abilities not found in most people. The Savant Syndrome skills involve striking feats of memory and often include arithmetic calculation and sometimes unusual abilities in art or music. There is actually a disproportionate regularity with which the triad of blindness, mental disability and musical genius occurs in savant syndrome. Examples include Derek Paravicini who has severe learning disability but can remember every song he has ever heard. Others with savant syndrome are not autistic, but develop these abilities later on in life usually as a result of some accident, illness or trauma. For example Alonzo Clemons was a regular child until he suffered brain damage as a result of a fall. Afterwards he learned to create accurate animal sculptures from clay using his photographic memory. Some scientists thus believe that the potential to be a genius is latent in all people but is obscured by normal functioning intellect. In the case of savants, the damage to the brain has somehow disrupted normal functioning and has allowed the brain to access these latent skills.
Savants are generally viewed as having exceptional spatial intelligence but verbal defects.
Many teachers see the theory as simple common sense. Some say that it validates what they already know: that students learn in different ways. On the other hand, James Traub's article in The New Republic notes that Gardner's system has not been accepted by most academics in intelligence or teaching.
The application of the theory of multiple intelligences varies widely. It runs the gamut from a teacher who, when confronted with a student having difficulties, uses a different approach to teach the material, to an entire school using MI as a framework. In general, those who subscribe to the theory strive to provide opportunities for their students to use and develop all the different intelligences, not just the few at which they naturally excel.
A Harvard-led study of 41 schools using the theory came to the conclusion that in these schools there was "a culture of hard work, respect, and caring; a faculty that collaborated and learned from each other; classrooms that engaged students through constrained but meaningful choices, and a sharp focus on enabling students to produce high-quality work.
Of the schools implementing Gardner's theory, the most well-known is New City School, in St. Louis, Missouri, which has been using the theory since 1988. The school's teachers have produced two books for teachers, Celebrating Multiple Intelligences and Succeeding With Multiple Intelligences and the principal, Thomas Hoerr, has written Becoming a Multiple Intelligences School as well as many articles on the practical applications of the theory. The school has also hosted four conferences, each attracting over 200 educators from around the world and remains a valuable resource for teachers interested in implementing the theory in their own classrooms.
The second major criticism is that it is fallacious to say that someone may be good in one intelligence but not in another. Every multiple domain IQ test ever normed (Wechsler Adult Intelligence Scale, Stanford-Binet IQ test, Ronald K. Hoeflin's Mega test) has shown that all the areas tested are correlated. This trend is also shown in tests like the Graduate Record Examination, the SAT, the PSAT, the ACT, etc., on every one of which each section correlates to a high degree with the others; the correlation rarely drops below 0.6 on the -1 to 1 scale. Hence, it has been argued that persons who excel in one type of intelligence usually excel in several others; and many times in all.
The third major criticism of multiple intelligences as an application in schools is that there is a risk of teachers excusing students from doing well in an area in which they are weak. Students who may not "naturally" learn to read and write well nevertheless need to read and write well. Similarly, the goal is for students to succeed in all areas defined as intelligence by Gardner, and not default to their strengths.
There is an inherent risk of students developing a sense of inferiority in given areas. Students who are identified as not being "musical" learners may have less incentive to become musical learners.
A methodological criticism is that the assessment of one's form of intelligence is usually determined via a self-administered test. The usual form asks the respondent 40-60 questions such as "Do you prefer to stand when working?" This sort of question leaves much room for assessment error, and does not conform to survey techniques and methodology such as double-blind testing.
Another criticism is that the distinction between developmental stage and "intelligence" is not sufficiently well accounted for. For example, the average five-year-old is more likely to answer "yes" to the question "Do you like to move about a lot?" than the average forty-year-old. Conversely, the older person is more likely to seem to have interpersonal "intelligence," which might be better labeled as a developed skill -- solving problems with others or speaking in public, for example.
Some of these criticisms arise from the fact that Gardner has not settled on a single definition of intelligence. He originally defined it as the ability to solve problems that have value in at least one culture, or as something that a student is interested in. However, he added a disclaimer that he has no fixed definition, and his classification is more of an artistic judgment than fact:
Ultimately, it would certainly be desirable to have an algorithm for the selection of an intelligence, such that any trained researcher could determine whether a candidate's intelligence met the appropriate criteria. At present, however, it must be admitted that the selection (or rejection) of a candidate's intelligence is reminiscent more of an artistic judgment than of a scientific assessment. (Gardner, Frames of Mind: The Theory of Multiple Intelligences, 1985)
Gardner argues that by calling linguistic and logical-mathematical abilities intelligences, but not artistic, musical, athletic, etc. abilities, the former are needlessly aggrandized. Many critics balk at this widening of the definition, saying that it ignores "the connotation of intelligence...[which] has always connoted the kind of thinking skills that make one successful in school.
Gardner writes "I balk at the unwarranted assumption that certain human abilities can be arbitrarily singled out as intelligence while others cannot Critics hold that given this statement, any interest or ability is now redefined as "intelligence". Thus, by adopting this theory, studying intelligence becomes difficult, because it diffuses into the broader concept of ability or talent. Gardner's addition of the naturalistic intelligence and conceptions of the existential and moral intelligences are seen as fruits of this diffusion. Defenders of the MI theory would argue that this is simply a recognition of the broad scope of inherent mental abilities, and that such an exhaustive scope by nature defies a simple, one-dimensional classification such as an assigned IQ value. They would claim that such one-dimensional values are typically of limited value in predicting the real world application of unique mental abilities.
A critical review of MI theory argues that there is little empirical evidence to support it:
"To date there have been no published studies that offer evidence of the validity of the multiple intelligences. In 1994 Sternberg reported finding no empirical studies. In 2000 Allix reported finding no empirical validating studies, and at that time Gardner and Connell conceded that there was "little hard evidence for MI theory" (2000, p. 292). In 2004 Sternberg and Grigerenko stated that there were no validating studies for multiple intelligences, and in 2004 Gardner asserted that he would be "delighted were such evidence to accrue" (p. 214), and he admitted that "MI theory has few enthusiasts among psychometricians or others of a traditional psychological background" because they require "psychometric or experimental evidence that allows one to prove the existence of the several intelligences" (2004, p. 214)." (Waterhouse, 2006a, p. 208).
Supporters of the MI theory would counter that such dependency is to be expected as this point, as scientific methodology aimed at uncovering intelligence was created under the traditional theory of intelligence, thus leaving a new theory the necessity of initially having to utilize the methodology of the old theory until new modes of scientific inquiry can be developed.
The same review presents evidence to demonstrate that cognitive neuroscience research does not support the theory of Multiple Intelligences:
"the human brain is unlikely to function via Gardner’s multiple intelligences. Taken together the evidence for the intercorrelations of subskills of IQ measures, the evidence for a shared set of genes associated with mathematics, reading, and g, and the evidence for shared and overlapping “what is it?” and “where is it?” neural processing pathways, and shared neural pathways for language, music, motor skills, and emotions suggest that it is unlikely that that each of Gardner’s intelligences could operate “via a different set of neural mechanisms” (1999, p. 99). Equally important, the evidence for the “what is it?” and “where is it?” processing pathways, for Kahneman’s two decision-making systems, and for adapted cognition modules suggests that these cognitive brain specializations have evolved to address very specific problems in our environment. Because Gardner claimed that that the intelligences are innate potentialities related to a general content area, MI theory lacks a rationale for the phylogenetic emergence of the intelligences." (From Waterhouse, 2006a, p. 213).
A number of articles have surveyed the use of Gardner's ideas and conclude that there is no evidence that his ideas work in practice. Steven A. Stahl found that most of the previous studies which claimed to show positive results had major flaws:
However, the continuing evolution of scientific understanding about the brain and its function suggest further insight into alternative neural pathways and cognitive sources will be likely. (Time, Jan 29, 2007).