Online research in philosophy

What are the elements from which the human mind is composed? What structures make up our _cognitive architecture?_ One of the most recent and intriguing answers to this question comes from the newly emerging interdisciplinary field of evolutionary psychology. Evolutionary psychologists defend a _massively modular_ conception of mental architecture which views the mind –including those parts responsible for such ‘central processes’ as belief revision and reasoning— as composed largely or perhaps even entirely of innate, special-purpose computational mechanisms or ‘modules’ that have been shaped by natural selection to handle the sorts of recurrent information processing problems that confronted our hunter-gatherer forebears (Cosmides and Tooby,192; Sperber, 1994; Samuels, 1998a).

Peter Carruthers, a leading philosopher of mind, provides a comprehensive development and defense of one of the guiding assumptions of evolutionary psychology: that the human mind is composed of a large number of semi-independent modules. Written with unusual clarity and directness, and surveying an extensive range of research in cognitive science, it will be essential reading for anyone with an interest in the nature and organization of the mind.

Two prevailing accounts of the structure of the mind have been provided, respectively, by the Dual System Theory and by the Massive Modularity Hypothesis. It has been claimed, however, that they cannot both be true at the same time, i.e., that they are incompatible and, thus, that one of them must be abandoned. I will offer some arguments to challenge this claim. I will show that a plausible understanding of each theory makes it possible for them both to be true at the same time. Moreover, I will argue that by appealing to each other they can offer a more complete and detailed account of the architecture of the mind.

Evolutionary psychologists claim that the mind contains “hundreds or thousands” of “genetically specified” modules, which are evolutionary adaptations for their cognitive functions. We argue that, while the adult human mind/brain typically contains a degree of modularization, its “modules” are neither genetically specified nor evolutionary adaptations. Rather, they result from the brain’s developmental plasticity, which allows environmental task demands a large role in shaping the brain’s information-processing structures. The brain’s developmental plasticity is our fundamental psychological adaptation, and the “modules” that result from it are adaptive responses to local conditions, not past evolutionary environments. If different individuals share common environ- ments, however, they may develop similar “modules,” and this process can mimic the development of genetically specified modules in the evolutionary psychologist’s sense.

This paper will sketch a model of the human mind according to which the mind’s structure is massively, but by no means wholly, modular. Modularity views in general will be motivated, elucidated, and defended, before the thesis of moderately massive modularity is explained and elaborated.

In the past few decades, research in the psychology of emotion has benefited greatly from being located in a firm evolutionary framework. It is argued that research in the psychology of mood might attain equal rigour by taking a similar approach. An evolutionary framework for mood research would be based on evolutionary psychology, the main thesis of which is the Massive Modularity Hypothesis. Translating the folk-psychological language of moods into the scientific language of modules might clarify many theoretical questions and provide a sound basis for empirical research. It is argued that such an evolutionary approach would reveal mood to be a much more heterogeneous category than emotion. While the six basic emotions identified by Paul Ekman are probably each subserved by a single module, prototypical moods such as elation, depression, anxiety and irritability are likely to be subserved by a wide range of modules. An evolutionary approach to mood might therefore lead to the elimination of the concept of mood from scientific psychology altogether.

This chapter investigates the extent to which claims of massive modular organization of the mind (espoused by some members of the evolutionary psychology research program) are consistent with the main elements of the simple heuristics research program. A number of potential sources of conflict between the two programs are investigated and defused. However, the simple heuristics program turns out to undermine one of the main arguments offered in support of massive modularity, at least as the latter is generally understood by philosophers. So one result of the argument will be to force us to re-examine the way in which the notion of modularity in cognitive science should best be characterized, if the thesis of massive modularity isn’t to be abandoned altogether. What is at stake in this discussion, is whether there is a well-motivated notion of ‘module’ such that we have good reason to think that the human mind must be massively modular in its organization. I shall be arguing (in the end) that there is.

The development of evolutionary approaches to psychology from Classical Ethology through Sociobiology to Evolutionary Psychology is outlined and the main tenets of today's Evolutionary Psychology briefly examined: the heuristic value of evolutionary thinking for psychology, the massive modularity thesis and the monomorphic mind thesis.

Evolutionary psychologists tend to view the mind as a large collection of evolved, functionally specialized mechanisms, or modules. Cosmides and Tooby (1994) have presented four arguments in favor of this model of the mind: the engineering argument, the error argument, the poverty of the stimulus argument, and combinatorial explosion. Fodor (2000) has discussed each of these four arguments and rejected them all. In the present paper, we present and discuss the arguments for and against the massive modularity hypothesis. We conclude that Cosmides and Tooby's arguments have considerable force and are too easily dismissed by Fodor.

Quartz (2002) argues that some recent findings about the evolution of the brain (Finlay & Darlington, 1995) are inconsistent with evolutionary psychologists’ massive modularity hypothesis. In substance, Quartz contends that since the volume of the neocortex evolved in a concerted manner, natural selection did not act on neocortical systems independently of each other, which is a necessary condition for the massive modularity of our cognition to be true. I argue however that Quartz’s argument fails to undermine the massive modularity hypothesis.