Modularity of Mind - Evolutionary Psychology and Massive Modularity

Evolutionary Psychology and Massive Modularity

Other perspectives on modularity come from evolutionary psychology, particularly from the work of Leda Cosmides and John Tooby. 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, when natural selection 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 and/or information processing 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, 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.

In contrast to modular mental structure, some theories posit domain-general processing, 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. Part of this argument is that a successful taxonomy of mental processes has yet to be developed.

Merlin 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)

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. Computer simulations of the evolution of neural nets suggests that modularity evolves because, compared to non-modular networks, connection costs are lower.