Modularity of mind
Modularity of mind is the notion that a mind
The concept of mind is understood in many different ways by many different traditions, ranging from panpsychism and animism to traditional and organized religious views, as well as secular and materialist philosophies. Most agree that minds are constituted by conscious experience and intelligent...

 may, at least in part, be composed of separate innate structures which have established evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

arily developed functional purposes. Somewhat different definitions of "module" have been proposed by different authorities.

Early investigations

Historically, questions regarding the functional architecture of the mind have been divided into two different theories of the nature of the faculties. The first can be characterized as a horizontal view because it refers to mental processes as if they are interactions between faculties such as memory, imagination, judgement, and perception, which are not domain specific
Domain specificity
Domain specificity is a theoretical position in cognitive science that argues that many aspects of cognition are supported by specialized, presumably evolutionarily specified, learning devices...

 (e.g., a judgement remains a judgement whether it refers to a perceptual experience or to the comprehension of language). The second can be characterized as a vertical view because it claims that the mental faculties are differentiated on the basis of domain specificity, are genetically determined, are associated with distinct neurological structures, and are computationally autonomous.

The vertical vision goes back to the 19th century movement called phrenology
Phrenology is a pseudoscience primarily focused on measurements of the human skull, based on the concept that the brain is the organ of the mind, and that certain brain areas have localized, specific functions or modules...

 and its founder Franz Joseph Gall
Franz Joseph Gall
Franz Joseph Gall was a neuroanatomist, physiologist, and pioneer in the study of the localization of mental functions in the brain.- Life :...

, who claimed that the individual mental faculties could be associated precisely, in a sort of one to one correspondence, with specific physical areas of the brain. Hence, someone's level of intelligence, for example, could be literally "read off" from the size of a particular bump on his posterior parietal lobe. This simplistic view of modularity has been disproven over the course of the last century.

Fodor's Modularity of Mind

In the 1980s, however, Jerry Fodor
Jerry Fodor
Jerry Alan Fodor is an American philosopher and cognitive scientist. He holds the position of State of New Jersey Professor of Philosophy at Rutgers University and is the author of many works in the fields of philosophy of mind and cognitive science, in which he has laid the groundwork for the...

 revived the idea of the modularity of mind, although without the notion of precise physical localizability. Drawing from Noam Chomsky
Noam Chomsky
Avram Noam Chomsky is an American linguist, philosopher, cognitive scientist, and activist. He is an Institute Professor and Professor in the Department of Linguistics & Philosophy at MIT, where he has worked for over 50 years. Chomsky has been described as the "father of modern linguistics" and...

's idea of the language acquisition device
Language acquisition device
The Language Acquisition Device is a postulated "organ" of the brain that is supposed to function as a congenital device for learning symbolic language . First proposed by Noam Chomsky, the LAD concept is an instinctive mental capacity which enables an infant to acquire and produce language. It is...

 and other work in linguistics
Linguistics is the scientific study of human language. Linguistics can be broadly broken into three categories or subfields of study: language form, language meaning, and language in context....

 as well as from the philosophy of mind
Philosophy of mind
Philosophy of mind is a branch of philosophy that studies the nature of the mind, mental events, mental functions, mental properties, consciousness and their relationship to the physical body, particularly the brain. The mind-body problem, i.e...

 and the implications of optical illusion
Optical illusion
An optical illusion is characterized by visually perceived images that differ from objective reality. The information gathered by the eye is processed in the brain to give a perception that does not tally with a physical measurement of the stimulus source...

s, he became one of its most articulate proponents with the 1983 publication of Modularity of Mind.

According to Fodor, a module falls somewhere between the behaviorist and cognitivist views of lower-level processes.

Behaviorism , also called the learning perspective , is a philosophy of psychology based on the proposition that all things that organisms do—including acting, thinking, and feeling—can and should be regarded as behaviors, and that psychological disorders are best treated by altering behavior...

 tried to replace the mind with reflexes which Fodor describes as encapsulated (cognitively impenetrable or unaffected by other cognitive domains) and non-inferential (straight pathways with no information added). Low level processes are unlike reflexes in that they are inferential. This can be demonstrated by poverty of the stimulus arguments in which the proximate stimulus, that which is initially received by the brain (such as the 2D image received by the retina), cannot account for the resulting output (for example, our 3D perception of the world), thus necessitating some form of computation.

In contrast, cognitivists
Cognitivism (psychology)
In psychology, cognitivism is a theoretical framework for understanding the mind that came into usage in the 1950s. The movement was a response to behaviorism, which cognitivists said neglected to explain cognition...

 saw lower level processes as continuous with higher level processes, being inferential and cognitively penetrable (influenced by other cognitive domains, such as beliefs). The latter has been shown to be untrue in some cases, such as with many visual illusions (ex. Müller-Lyer illusion), which can persist despite a person's awareness of their existence. This is taken to indicate that other domains, including one's beliefs, cannot influence such processes.

Fodor arrives at the conclusion that such processes are inferential like higher order processes and encapsulated in the same sense as reflexes.

Although he argued for the modularity of "lower level" cognitive processes in Modularity of Mind he also argued that higher level cognitive processes are not modular since they have dissimilar properties. The Mind Doesn't Work That Way, a reaction to Steven Pinker
Steven Pinker
Steven Arthur Pinker is a Canadian-American experimental psychologist, cognitive scientist, linguist and popular science author...

's How the Mind Works
How the Mind Works
How the Mind Works is a book by Canadian-American cognitive scientist Steven Pinker, published in 1997. The book attempts to explain some of the human mind's poorly understood functions and quirks in evolutionary terms...

, is devoted to this subject.

Fodor (1983) states that modular systems must—at least to "some interesting extent"—fulfill certain properties:
  1. Domain specificity, modules only operate on certain kinds of inputs—they are specialised
  2. Informational encapsulation, modules need not refer to other psychological systems in order to operate
  3. Obligatory firing, modules process in a mandatory manner
  4. Fast speed, probably due to the fact that they are encapsulated (thereby needing only to consult a restricted database) and mandatory (time need not be wasted in determining whether or not to process incoming input)
  5. Shallow outputs, the output of modules is very simple
  6. Limited accessibility
  7. Characteristic ontogeny
    Ontogeny is the origin and the development of an organism – for example: from the fertilized egg to mature form. It covers in essence, the study of an organism's lifespan...

    , there is a regularity of development
  8. Fixed neural architecture.

Pylyshyn (1999) has argued that while these properties tend to occur with modules, one stands out as being the real signature of a module; that is the encapsulation of the processes inside the module from both cognitive influence and from cognitive access. This is referred to as "information encapsulation". One example is that conscious awareness of the Müller-Lyer illusion being an illusion does not correct the visual processing.

Evolutionary psychology and Massive Modularity

Other perspectives on modularity come from evolutionary psychology
Evolutionary psychology
Evolutionary psychology is an approach in the social and natural sciences that examines psychological traits such as memory, perception, and language from a modern evolutionary perspective. It seeks to identify which human psychological traits are evolved adaptations, that is, the functional...

, particularly from the work of Leda Cosmides
Leda Cosmides
Leda Cosmides, is an American psychologist, who, together with anthropologist husband John Tooby, helped develop the field of evolutionary psychology....

 and John Tooby
John Tooby
John Tooby is an American anthropologist, who, together with psychologist wife Leda Cosmides, helped pioneer the field of evolutionary psychology....

. This perspective suggests that modules are units of mental processing that evolved in response to selection pressures. On this view, much modern human psychological activity is rooted in adaptations that occurred earlier in human evolution
Human evolution
Human evolution refers to the evolutionary history of the genus Homo, including the emergence of Homo sapiens as a distinct species and as a unique category of hominids and mammals...

, when natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....

 was forming the modern human species.

Evolutionary psychologists propose that the mind is made up of genetically influenced and domain-specific, mental algorithms or computational modules, designed to solve specific evolutionary problems of the past. Cosmides and Tooby also state in a brief "primer" on their website,, that “…the brain is a physical system. It functions like a computer,” “…the brain’s function is to process information,” “different neural circuits are specialized for solving different adaptive problems,” and “our modern skulls house a stone age mind.”

The definition of module has caused confusion and dispute. J. A. Fodor initially defined module as "functionally specialized cognitive systems" that have nine features but not necessarily all at the same time. In his views modules can be found in peripheral processing such as low-level visual processing but not in central processing. Later he narrowed the two essential features to domain-specificity and information encapsulation. Frankenhuis and Ploeger write that domain-specificity means that "a given cognitive mechanism accepts, or is specialized to operate on, only a specific class of information". Information encapsulation means that information processing in the module cannot be affected by information in the rest of the brain. One example being awareness that certain optical illusion, caused by low level processing, are false not preventing the illusions from persisting.

Evolutionary pscyhologists instead usually define modules as functionally specialized cognitive systems that are domain-specific and may also contain innate knowledge about the class of information processed. Modules can be found also for central processing. This theory is sometimes referred to as Massive Modularity.

Several groups of critics, including psychologists working within evolutionary frameworks, argue that the massively modular theory of mind does little to explain adaptive psychological traits. Proponents of other models of the mind argue that the computational theory of mind is no better at explaining human behavior than a theory with mind entirely a product of the environment. Even within evolutionary psychology there is discussion about the degree of modularity, either as a few generalist modules or as many highly specific modules.

Wallace (2010) observes that the evolutionary psychologists' definition of 'mind' have been heavily influenced by cognitivism
Cognitivism (psychology)
In psychology, cognitivism is a theoretical framework for understanding the mind that came into usage in the 1950s. The movement was a response to behaviorism, which cognitivists said neglected to explain cognition...

 and/or information processing
Information processing
Information processing is the change of information in any manner detectable by an observer. As such, it is a process which describes everything which happens in the universe, from the falling of a rock to the printing of a text file from a digital computer system...

 definitions of the mind Critics point out that these assumptions underlying Evolutionary Psychologists’ hypotheses are controversial and have been contested by some psychologists, philosophers, and neuroscientists. For example, Jaak Panksepp
Jaak Panksepp
Jaak Panksepp is an Estonian-born American psychologist, a psychobiologist, a neuroscientist, the Baily Endowed Chair of Animal Well-Being Science for the Department of Veterinary and Comparative Anatomy, Pharmacology, and Physiology at Washington State University's College of Veterinary Medicine,...

, an affective neuroscientist, point to the "remarkable degree of neocortical plasticity within the human brain, especially during development" and states that "the developmental interactions among ancient special-purpose circuits and more recent general-purpose brain mechanisms can generate many of the ‘modularized’ human abilities that evolutionary psychology has entertained."

Philosopher David Buller agrees with the general argument that the human mind has evolved over time but disagree with the specific claims evolutionary psychologists make. Buller has argued that the contention that the mind consists of thousands of modules, including sexually dimorphic jealousy and parental investment modules, are unsupported by the available empirical evidence. However, Buller has also stated that even if massive modularity is false this does not necessarily have broad implications for evolutionary psychology. Evolution may create innate motives even without innate knowledge.

There are alternatives to the "massively modular" view of the mind. Donald argues that over evolutionary time the mind has gained adaptive advantage from being a general problem solver. The mind, as described by Donald, includes module-like "central" mechanisms, in addition to more recently evolved "domain-general" mechanisms.

A 2010 review by evolutionary psychologists stated that a theory of one or a few domain-general mechanisms such as "rationality" has several problem: 1. Evolutionary theories using the idea of numerous domain-specific adaptions have produced testable predictions that have been empirically confirmed; the theory of domain-general rational thought has produced no such predictions or confirmations. 2. The rapidity of responses such as jealousy due to infidelity indicates a domain-specific dedicated module rather than a general, deliberate, rational calculation of consequences. 3. Reactions may occur instinctively (consistent with innate knowledge) even if a person have not learned such knowledge. One example being that in the ancestral environment it is unlikely that males during development learn that infidelity (usually secret) may cause paternal uncertainty (from observing the phenotypes of children born many months later and making a statistical conclusion from the phenotype dissimilarity to the cuckolded fathers).

For some research done to address these criticisms, see Daly and Wilson's response to Buller's criticism above, and Bryant (2006) On Hasty Generalization About Evolutionary Psychology

With respect to general purpose problem solvers, see Barkow, Cosmides, and Tooby (1992) The Adapted Mind: Evolutionary Psychology and The Generation of Culture for their argument that a purely general problem solving mechanism is impossible to build due to the frame problem
Frame problem
In artificial intelligence, the frame problem was initially formulated as the problem of expressing a dynamical domain in logic without explicitly specifying which conditions are not affected by an action. John McCarthy and Patrick J. Hayes defined this problem in their 1969 article, Some...


Arguments against modularity

In contrast to modular mental structure, some theories posit domain-general processing
Domain-general learning
Domain-general learning theories of development hold that we develop a global knowledge structure which contains cohesive, whole knowledge internalized from experience...

, in which mental activity is distributed across the brain and cannot be decomposed, even abstractly, into independent units. A staunch defender of this view is William Uttal, who argues in The New Phrenology (2003) that there are serious philosophical, theoretical, and methodological problems with the entire enterprise of trying to localise cognitive processes in the brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

. Part of this argument is that a successful taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...

 of mental processes has yet to be developed.

See also

  • Modularity
    Modularity is a general systems concept, typically defined as a continuum describing the degree to which a system’s components may be separated and recombined. It refers to both the tightness of coupling between components, and the degree to which the “rules” of the system architecture enable the...

  • Language module
    Language module
    Language module refers to a hypothesized structure in the human brain or cognitive system that some psycholinguists claim contains innate capacities for language...

  • Visual modularity
    Visual modularity
    In cognitive neuroscience, visual modularity is an organizational concept concerning how vision works. The way in which the primate visual system operates is currently under intense scientific scrutiny...

  • Society of Mind
    Society of Mind
    The Society of Mind is both the title of a book and the name of a theory of natural intelligence as written and developed by Marvin Minsky.-Minsky's model:...

     which proposes the mind is made up of agents
  • Jerry Fodor on mental architecture
    Jerry Fodor on mental architecture
    Jerry Fodor is notable for his important and influential ideas on a hypothesized "structure" of the mind or, what has often been called mental architecture.-Fodor and Chomsky:...

  • Neuroplasticity
    Neuroplasticity is a non-specific neuroscience term referring to the ability of the brain and nervous system in all species to change structurally and functionally as a result of input from the environment. Plasticity occurs on a variety of levels, ranging from cellular changes involved in...

Further reading

  • Barrett, H.C., and Kurzban, R. (2006). Modularity in cognition: Framing the debate. Psychological Review
    Psychological Review
    Psychological Review is a scientific journal that publishes articles on psychological theory. It was founded by Princeton psychologist James Mark Baldwin and Columbia psychologist James McKeen Cattell in 1894 as a publication vehicle for psychologists not connected with the Clark laboratory of G....

    , 113,
    628-647. Full text
  • Pylyshyn, Z.W. (1984). Computation and cognition: Toward a foundation for cognitive science. Cambridge, MA: MIT Press (Also available through CogNet).
  • Animal Minds : Beyond Cognition to Consciousness Donald R. Griffin, University of Chicago Press, 2001 (ISBN 0226308650)

Online videos

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