Is the Human Mind Massively Modular?

The modularity of mind debate centers around whether human minds consist of discrete neural units with distinct functions. A central arena for the debate is evolutionary psychology and “massive modularity”. This essay gives a brief history of our attempts to map the brain to function, critically appraises some key ideas, including Fodorian modularity, while offering empirical evidence to address some criticisms of evolutionary psychology’s modularity.

It is important to acknowledge some shameful aspects of early attempts to map the brain to function, including “phrenology”; the racist and sexist pseudoscience of measuring bumps on the skull to ‘’localise’’ mental traits, which was used to peddle myths about inherent intelligence differences between sexes and races (Gall, 1884). Despite misguided origins and some critics even labelling it as “the new phrenology” (Uttal, 2001), ‘’localisation of function’’ has some merit. Early lesion studies show that some regions of the brain are associated with specific functions, such as “Wernicke’s area” associated with understanding language and “Broca’s area” associated with speech production (Broca, 1861; Wernicke, 1885). Findings like these, coupled with technological developments such as Functional Magnetic Resonance Imaging (fMRI), informing on which areas of the brain are using oxygen at different times, further illuminate links between specific parts of the brain and their functions, although not to the comprehensive degree the technology initially appeared to promise (Aue et al., 2009).

Alternative approaches point to more general-purpose mechanisms and a degree of neocortical plasticity, the idea that neural networks can reorganise structurally and functionally, for example, in response to injury (Ferreira et al., 2014; Panksepp & Panksepp, 2000). Evolutionary psychology is considered extreme in its endorsement of “massive modularity”: the idea that human minds evolved modularly like all other complex biological systems, and are almost entirely made up of different functional adaptations (Bechtel, 2003; Samuels, 2000; Carruthers, 2006; Machery, 2007). Evolutionary psychology contends that the ultimate conditioning of the “environments of evolutionary adaptedness” shaped us with problem-solving modules that act like organs of the mind (Tooby & Cosmides, 1990).

Evolutionary psychology coincides well with cognitive psychology in understanding the brain as an organic “wet computer” with carbon-based neurons specialised in the…