Intelligence has been defined in many different ways including the
capacity for logic, understanding, self-awareness, learning, emotional
knowledge, reasoning, planning, creativity, and problem solving. It
can be more generally described as the ability to perceive or infer
information, and to retain it as knowledge to be applied towards
adaptive behaviors within an environment or context.
Intelligence is most widely studied in humans but has also been
observed in both non-human animals and in plants.
machines is called artificial intelligence, which is commonly
implemented in computer systems using program software.
1 History of the term
3.1 Cultural influences on the interpretation of human intelligence
4 In animals
4.1 g factor in non-humans
5 In plants
6 Artificial intelligence
7 See also
9 Further reading
10 External links
History of the term
Main article: Nous
The English word intelligence is a translation for the Latin nouns
intelligentia or intellēctus, which in turn derive from the verb
intelligere, to comprehend or perceive. In the
Middle Ages intellectus
became the scholarly technical term for understanding, and a
translation for the Greek philosophical term nous. This term was
however strongly linked to the metaphysical and cosmological theories
of teleological scholasticism, including theories of the immortality
of the soul, and the concept of the
Active Intellect (also known as
the Active Intelligence). This entire approach to the study of nature
was strongly rejected by the early modern philosophers such as Francis
Bacon, Thomas Hobbes, John Locke, and David Hume, all of whom
preferred the word "understanding" (instead of "intellectus" or
"intelligence") in their English philosophical works. Hobbes for
example, in his Latin De Corpore, used "intellectus intelligit"
(translated in the English version as "the understanding
understandeth") as a typical example of a logical absurdity. The
term "intelligence" has therefore become less common in English
language philosophy, but it has later been taken up (with the
scholastic theories which it now implies) in more contemporary
The definition of intelligence is controversial. Some groups of
psychologists have suggested the following definitions:
From "Mainstream Science on Intelligence" (1994), an op-ed statement
in the Wall Street Journal signed by fifty-two researchers (out of 131
total invited to sign):
A very general mental capability that, among other things, involves
the ability to reason, plan, solve problems, think abstractly,
comprehend complex ideas, learn quickly and learn from experience. It
is not merely book learning, a narrow academic skill, or test-taking
smarts. Rather, it reflects a broader and deeper capability for
comprehending our surroundings—"catching on," "making sense" of
things, or "figuring out" what to do.
From "Intelligence: Knowns and Unknowns" (1995), a report published by
the Board of Scientific Affairs of the American Psychological
Individuals differ from one another in their ability to understand
complex ideas, to adapt effectively to the environment, to learn from
experience, to engage in various forms of reasoning, to overcome
obstacles by taking thought. Although these individual differences can
be substantial, they are never entirely consistent: a given person's
intellectual performance will vary on different occasions, in
different domains, as judged by different criteria. Concepts of
"intelligence" are attempts to clarify and organize this complex set
of phenomena. Although considerable clarity has been achieved in some
areas, no such conceptualization has yet answered all the important
questions, and none commands universal assent. Indeed, when two dozen
prominent theorists were recently asked to define intelligence, they
gave two dozen, somewhat different, definitions.
Besides those definitions, psychology and learning researchers also
have suggested definitions of intelligence such as:
Judgment, otherwise called "good sense", "practical sense",
"initiative", the faculty of adapting one's self to circumstances ...
The aggregate or global capacity of the individual to act
purposefully, to think rationally, and to deal effectively with his
"...the resultant of the process of acquiring, storing in memory,
retrieving, combining, comparing, and using in new contexts
information and conceptual skills".
To my mind, a human intellectual competence must entail a set of
skills of problem solving — enabling the individual to resolve
genuine problems or difficulties that he or she encounters and, when
appropriate, to create an effective product — and must also entail
the potential for finding or creating problems — and thereby laying
the groundwork for the acquisition of new knowledge.
The ability to deal with cognitive complexity.
Sternberg & Salter
Goal-directed adaptive behavior.
The theory of Structural Cognitive Modifiability describes
intelligence as "the unique propensity of human beings to change or
modify the structure of their cognitive functioning to adapt to the
changing demands of a life situation".
Legg & Hutter
A synthesis of 70+ definitions from psychology, philosophy, and AI
Intelligence measures an agent’s ability to achieve
goals in a wide range of environments", which has been
F = T ∇ S
displaystyle _ tau
Intelligence is a force, F, that acts so as to maximize future
freedom of action. It acts to maximize future freedom of action, or
keep options open, with some strength T, with the diversity of
possible accessible futures, S, up to some future time horizon, τ. In
short, intelligence doesn't like to get trapped".
Human intelligence is the intellectual power of humans, which is
marked by complex cognitive feats and high levels of motivation and
Intelligence enables humans to remember
descriptions of things and use those descriptions in future behaviors.
It is a cognitive process. It gives humans the cognitive abilities to
learn, form concepts, understand, and reason, including the capacities
to recognize patterns, comprehend ideas, plan, solve problems, and use
language to communicate.
Intelligence enables humans to experience and
Note that much of the above definition applies also to the
intelligence of non-human animals.
Cultural influences on the interpretation of human intelligence
Human intelligence §
Intelligence across cultures
Main article: Animal cognition
The common chimpanzee can use tools. This chimpanzee is using a stick
to get food.
Although humans have been the primary focus of intelligence
researchers, scientists have also attempted to investigate animal
intelligence, or more broadly, animal cognition. These researchers are
interested in studying both mental ability in a particular species,
and comparing abilities between species. They study various measures
of problem solving, as well as numerical and verbal reasoning
abilities. Some challenges in this area are defining intelligence so
that it has the same meaning across species (e.g. comparing
intelligence between literate humans and illiterate animals), and also
operationalizing a measure that accurately compares mental ability
across different species and contexts.
Wolfgang Köhler's research on the intelligence of apes is an example
of research in this area. Stanley Coren's book, The
Dogs is a notable book on the topic of dog intelligence. (See
also: Dog intelligence.) Non-human animals particularly noted and
studied for their intelligence include chimpanzees, bonobos (notably
the language-using Kanzi) and other great apes, dolphins, elephants
and to some extent parrots, rats and ravens.
Cephalopod intelligence also provides important comparative study.
Cephalopods appear to exhibit characteristics of significant
intelligence, yet their nervous systems differ radically from those of
backboned animals. Vertebrates such as mammals, birds, reptiles and
fish have shown a fairly high degree of intellect that varies
according to each species. The same is true with arthropods.
g factor in non-humans
Main article: g Factor in Non-Humans
Evidence of a general factor of intelligence has been observed in
non-human animals. The general factor of intelligence, or g factor, is
a psychometric construct that summarizes the correlations observed
between an individual’s scores on a wide range of cognitive
abilities. First described in humans, the g factor has since been
identified in a number of non-human species.
Cognitive ability and intelligence cannot be measured using the same,
largely verbally dependent, scales developed for humans. Instead,
intelligence is measured using a variety of interactive and
observational tools focusing on innovation, habit reversal, social
learning, and responses to novelty. Studies have shown that g is
responsible for 47% of the individual variance in cognitive ability
measures in primates and between 55% and 60% of the variance in
mice (Locurto, Locurto). These values are similar to the accepted
variance in IQ explained by g in humans (40-50%).
Main article: Plant intelligence
It has been argued that plants should also be classified as
intelligent based on their ability to sense and model external and
internal environments and adjust their morphology, physiology and
phenotype accordingly to ensure self-preservation and
A counter argument is that intelligence is commonly understood to
involve the creation and use of persistent memories as opposed to
computation that does not involve learning. If this is accepted as
definitive of intelligence, then it includes the artificial
intelligence of robots capable of "machine learning", but excludes
those purely autonomic sense-reaction responses that can be observed
in many plants. Plants are not limited to automated sensory-motor
responses, however, they are capable of discriminating positive and
negative experiences and of 'learning' (registering memories) from
their past experiences. They are also capable of communication,
accurately computing their circumstances, using sophisticated
cost–benefit analysis and taking tightly controlled actions to
mitigate and control the diverse environmental stressors.
Main article: Artificial intelligence
Artificial intelligence (or AI) is both the intelligence of machines
and the branch of computer science which aims to create it, through
"the study and design of intelligent agents" or "rational agents",
where an intelligent agent is a system that perceives its environment
and takes actions which maximize its chances of success.
Achievements in artificial intelligence include constrained and
well-defined problems such as games, crossword-solving and optical
character recognition and a few more general problems such as
autonomous cars. General intelligence or strong AI has not yet
been achieved and is a long-term goal of AI research.
Among the traits that researchers hope machines will exhibit are
reasoning, knowledge, planning, learning, communication, perception,
and the ability to move and to manipulate objects. In the
field of artificial intelligence there is no consensus on how closely
the brain should be simulated.
Neuroscience and intelligence
Outline of human intelligence
Self-test of Intelligence
Theory of multiple intelligences
^ Maich, Aloysius (1995). "A Hobbes Dictionary". Blackwell: 305
^ Nidditch, Peter. "Foreword". An Essay Concerning Human
Understanding. Oxford University Press. p. xxii
^ English Archived 11 March 2014 at the Wayback Machine., and Latin
version Archived 5 November 2013 at the Wayback Machine..
^ This paragraph almost verbatim from Goldstein, Sam; Princiotta,
Dana; Naglieri, Jack A., Eds. (2015). Handbook of Intelligence:
Evolutionary Theory, Historical Perspective, and Current Concepts. New
York, Heidelberg, Dordrecht, London: Springer. p. 3.
^ a b S. Legg; M. Hutter. "A Collection of Definitions of
Intelligence". 157: 17–24.
^ Gottfredson & 1997777, pp. 17–20
^ Gottfredson, Linda S. (1997). "Mainstream Science on Intelligence
(editorial)" (PDF). Intelligence. 24: 13–23.
doi:10.1016/s0160-2896(97)90011-8. ISSN 0160-2896. Archived (PDF)
from the original on 22 December 2014.
^ Neisser, Ulrich; Boodoo, Gwyneth; Bouchard, Thomas J.; Boykin, A.
Wade; Brody, Nathan; Ceci, Stephen J.; Halpern, Diane F.; Loehlin,
John C.; Perloff, Robert; Sternberg, Robert J.; Urbina, Susana (1996).
"Intelligence: Knowns and unknowns" (PDF). American Psychologist. 51:
77–101. doi:10.1037/0003-066x.51.2.77. ISSN 0003-066X. Archived
(PDF) from the original on 28 March 2016. Retrieved 9 October
^ Binet, Alfred (1916) . "New methods for the diagnosis of the
intellectual level of subnormals". The development of intelligence in
children: The Binet-Simon Scale. E.S. Kite (Trans.). Baltimore:
Williams & Wilkins. pp. 37–90. Retrieved 10 July 2010.
originally published as Méthodes nouvelles pour le diagnostic du
niveau intellectuel des anormaux. L'Année Psychologique, 11,
^ Wechsler, D (1944). The measurement of adult intelligence.
Baltimore: Williams & Wilkins. ISBN 0-19-502296-3.
OCLC 219871557. ASIN = B000UG9J7E
^ Humphreys, L. G. (1979). "The construct of general intelligence".
Intelligence. 3 (2): 105–120.
^ Frames of mind: The theory of multiple intelligences. New York:
Basic Books. 1993. ISBN 0-465-02510-2. OCLC 221932479.
^ Gottfredson, L. (1998). "The General
Intelligence Factor" (pdf).
Scientific American Presents. 9 (4): 24–29. Archived (PDF) from the
original on 7 March 2008. Retrieved 18 March 2008.
^ Sternberg RJ; Salter W (1982). Handbook of human intelligence.
Cambridge, UK: Cambridge University Press. ISBN 0-521-29687-0.
^ Feuerstein, R., Feuerstein, S., Falik, L & Rand, Y. (1979;
2002). Dynamic assessments of cognitive modifiability. ICELP Press,
Jerusalem: Israel; Feuerstein, R. (1990). The theory of structural
modifiability. In B. Presseisen (Ed.),
Learning and thinking styles:
Classroom interaction. Washington, DC: National Education Associations
^ S. Legg; M. Hutter (2007). "Universal Intelligence: A
Machine Intelligence". Minds & Machines. 17 (4): 391–444.
^ "TED Speaker: Alex Wissner-Gross: A new equation for intelligence".
TED.com. Archived from the original on 4 September 2016. Retrieved 7
^ Tirri, Nokelainen. Measuring Multiple Intelligences and Moral
Sensitivities in Education. Springer. ISBN 978-94-6091-758-5.
Archived from the original on 2 August 2017.
^ Coren, Stanley (1995). The
Intelligence of Dogs. Bantam Books.
ISBN 0-553-37452-4. OCLC 30700778.
^ a b Reader, S. M., Hager, Y., & Laland, K. N. (2011). The
evolution of primate general and cultural intelligence. Philosophical
Transactions of the Royal Society B: Biological Sciences, 366(1567),
^ Kamphaus, R. W. (2005). Clinical assessment of child and adolescent
intelligence. Springer Science & Business Media.
^ Trewavas, Anthony (September 2005). "Green plants as intelligent
organisms". Trends in Plant Science. 10 (9): 413–419.
doi:10.1016/j.tplants.2005.07.005. PMID 16054860.
^ Trewavas, A. (2002). "Mindless mastery". Nature. 415 (6874): 841.
doi:10.1038/415841a. PMID 11859344.
^ Goh, C. H.; Nam, H. G.; Park, Y. S. (2003). "Stress memory in
plants: A negative regulation of stomatal response and transient
induction of rd22 gene to light in abscisic acid-entrained Arabidopsis
plants". The Plant Journal. 36 (2): 240–255.
doi:10.1046/j.1365-313X.2003.01872.x. PMID 14535888.
^ Volkov, A. G.; Carrell, H.; Baldwin, A.; Markin, V. S. (2009).
"Electrical memory in Venus flytrap". Bioelectrochemistry. 75 (2):
^ Rensing, L.; Koch, M.; Becker, A. (2009). "A comparative approach to
the principal mechanisms of different memory systems".
Naturwissenschaften. 96 (12): 1373–1384.
^ a b Goebel, Randy; Poole, David L.; Mackworth, Alan K. (1997).
Computational intelligence: A logical approach (pdf). Oxford
[Oxfordshire]: Oxford University Press. p. 1.
ISBN 0-19-510270-3. Archived (PDF) from the original on 7 March
^ a b Russell, Stuart J.; Norvig, Peter (2003). Artificial
intelligence: A modern approach. Englewood Cliffs, N.J.: Prentice
Hall. ISBN 0-13-790395-2. OCLC 51325314.
Binet, Alfred; Simon, Th. (1916). The development of intelligence in
children: The Binet-Simon Scale. Publications of the Training School
at Vineland New Jersey Department of Research No. 11. E. S. Kite
(Trans.). Baltimore: Williams & Wilkins. Retrieved 18 July
Terman, Lewis Madison; Merrill, Maude A. (1937). Measuring
intelligence: A guide to the administration of the new revised
Stanford-Binet tests of intelligence. Riverside textbooks in
education. Boston (MA): Houghton Mifflin. OCLC 964301.
Wolman, Benjamin B., ed. (1985). Handbook of Intelligence. consulting
editors: Douglas K. Detterman, Alan S. Kaufman, Joseph D. Matarazzo.
New York (NY): Wiley. ISBN 978-0-471-89738-5. This handbook
includes chapters by Paul B. Baltes, Ann E. Boehm, Thomas J. Bouchard,
Jr., Nathan Brody, Valerie J. Cook, Roger A. Dixon, Gerald E. Gruen,
J. P. Guilford, David O. Herman, John L. Horn, Lloyd G. Humphreys,
George W. Hynd, Randy W. Kamphaus, Robert M. Kaplan, Alan S. Kaufman,
Nadeen L. Kaufman, Deirdre A. Kramer, Roger T. Lennon, Michael Lewis,
Joseph D. Matarazzo, Damian McShane, Mary N. Meeker, Kazuo Nihira,
Thomas Oakland, Ronald Parmelee, Cecil R. Reynolds, Nancy L. Segal,
Robert J. Sternberg, Margaret Wolan Sullivan, Steven G. Vandenberg,
George P. Vogler, W. Grant Willis, Benjamin B. Wolman, James W.
Soo-Sam, and Irla Lee Zimmerman.
Bock, Gregory; Goode, Jamie; Webb, Kate, eds. (2000). The Nature of
Intelligence. Novartis Foundation Symposium 233. Chichester: Wiley.
doi:10.1002/0470870850. ISBN 978-0471494348. Retrieved 16 July
2010. Lay summary (16 May 2013).
Blakeslee, Sandra; Hawkins, Jeff (2004). On intelligence. New York:
Times Books. ISBN 0-8050-7456-2. OCLC 55510125. CS1
maint: Multiple names: authors list (link)
Stanovich, Keith (2009). What
Intelligence Tests Miss: The Psychology
of Rational Thought. New Haven (CT): Yale University Press.
ISBN 978-0-300-12385-2. Lay summary (6 November 2013).
Flynn, James R. (2009). What Is Intelligence: Beyond the Flynn Effect
(expanded paperback ed.). Cambridge: Cambridge University Press.
ISBN 978-0-521-74147-7. Lay summary (18 July 2010).
Mackintosh, N. J. (2011). IQ and
Intelligence (second ed.).
Oxford: Oxford University Press. ISBN 978-0-19-958559-5. Lay
summary (9 February 2012).
Sternberg, Robert J.; Kaufman, Scott Barry, eds. (2011). The Cambridge
Handbook of Intelligence. Cambridge: Cambridge University Press.
ISBN 9780521739115. Lay summary (22 July 2013). The
Cambridge Handbook includes chapters by N. J. Mackintosh, Susana
Urbina, John O. Willis, Ron Dumont, Alan S. Kaufman, Janet E.
Davidson, Iris A. Kemp, Samuel D. Mandelman, Elena L. Grigorenko,
Raymond S. Nickerson, Joseph F. Fagan, L. Todd Rose, Kurt Fischer,
Christopher Hertzog, Robert M. Hodapp, Megan M. Griffin, Meghan M.
Burke, Marisa H. Fisher, David Henry Feldman, Martha J. Morelock,
Sally M. Reis, Joseph S. Renzulli, Diane F. Halpern, Anna S. Beninger,
Carli A. Straight, Lisa A. Suzuki, Ellen L. Short, Christina S. Lee,
Christine E. Daley, Anthony J. Onwuegbuzie, Thomas R. Zentall, Liane
Gabora, Anne Russon, Richard J. Haier, Ted Nettelbeck, Andrew R. A.
Conway, Sarah Getz, Brooke Macnamara, Pascale M. J. Engel de Abreu,
David F. Lohman, Joni M. Lakin, Keith E. Stanovich, Richard F. West,
Maggie E. Toplak, Scott Barry Kaufman, Ashok K. Goel, Jim Davies,
Katie Davis, Joanna Christodoulou, Scott Seider, Howard Gardner,
Robert J. Sternberg, John D. Mayer, Peter Salovey, David Caruso,
Lillia Cherkasskiy, Richard K. Wagner, John F. Kihlstrom, Nancy
Cantor, Soon Ang, Linn Van Dyne, Mei Ling Tan, Glenn Geher, Weihua
Niu, Jillian Brass, James R. Flynn, Susan M. Barnett, Heiner
Rindermann, Wendy M. Williams, Stephen J. Ceci, Ian J. Deary, G. David
Batty, Colin DeYoung, Richard E. Mayer, Priyanka B. Carr, Carol S.
Dweck, James C. Kaufman, Jonathan A. Plucker, Ursula M. Staudinger,
Judith Glück, Phillip L. Ackerman, and Earl Hunt.
Wikimedia Commons has media related to Intelligence.
Look up intelligence in Wiktionary, the free dictionary.
Wikiquote has quotations related to: Intelligence
Intelligence on In Our Time at the BBC.
History of Influences in the Development of
Intelligence Theory and
Testing - Developed by Jonathan Plucker at Indiana University
The Limits of Intelligence: The laws of physics may well prevent the
human brain from evolving into an ever more powerful thinking machine
by Douglas Fox in Scientific American, June 14, 2011.
A Collection of Definitions of Intelligence
Scholarly journals and societies
Intelligence (journal homepage)
International Society for
Intelligence Research (homepage)
Philosophy of mind
Concept and object
Hard problem of consciousness
Language of thought
Problem of other minds
Philosophy of artificial intelligence / information /
perception / self
Human intelligence topics
Fluid and crystallized intelligence
Models and theories
Fluid and crystallized intelligence
Areas of research
Evolution of human intelligence
Heritability of IQ
Intelligence and environment / health / longevity /
neuroscience / race
Outline of human intelligence / thought