Online research in philosophy

_The emerging discipline of evolutionary developmental biology has opened up many new _ _lines of investigation into morphological evolution. Here I explore how two of the core _ _theoretical concepts in ‘evo-devo’ – modularity and homology – apply to evolutionary _ _psychology. I distinguish three sorts of module - developmental, functional and mental _ _modules and argue that mental modules need only be ‘virtual’ functional modules. _ _Evolutionary psychologists have argued that separate mental modules are solutions to _ _separate evolutionary problems. I argue that the structure of developmental modules in _ _an organism helps determine what counts as a separate evolutionary problem for that _ _organism. I suggest that homology as an organizing principle for research in _ _evolutionary psychology, has been severely neglected in favor of analogy (adaptive _ _function). I consider some arguments suggesting that determining homology is less _ _epistemically demanding than determining adaptive function and argue that _ _psychological categories defined by homology are, in fact, more suitable objects of _ _psychological - and particularly neuropsychological - investigation than categories _ _defined by analogy. _.

In recent years evolutionary psychologists have developed and defended the Massive Modularity Hypothesis, which maintains that our cognitive architecture—including the part that subserves ‘central processing’ —is largely or perhaps even entirely composed of innate, domain-specific computational mechanisms or ‘modules’. In this paper I argue for two claims. First, I show that the two main arguments that evolutionary psychologists have offered for this general architectural thesis fail to provide us with any reason to prefer it to a competing picture of the mind which I call the Library Model of Cognition. Second, I argue that this alternative model is compatible with the central theoretical and methodological commitments of evolutionary psychology. Thus I argue that, at present, the endorsement of the Massive Modularity Hypothesis by evolutionary psychologists is both unwarranted and unmotivated.

It is commonly supposed that evolutionary explanations of cognitive phenomena involve the assumption that the capacities to be explained are both innate and modular. This is understandable: independent selection of a trait requires that it be both heritable and largely decoupled from other `nearby' traits. Cognitive capacities realized as innate modules would certainly satisfy these contraints. A viable evolutionary cognitive psychology, however, requires neither extreme nativism nor modularity, though it is consistent with both. In this paper, we seek to show that rather weak assumptions about innateness and modularity are consistent with evolutionary explanations of cognitive capacities. Evolutionary pressures can affect the degree to which the development of a capacity is canalized by biasing acquisition/ learning in ways that favor development of concepts and capacities that proved adaptive to an organism's ancestors. q 1999 Elsevier Science B.V. All rights reserved.

This commentary discusses the logic of inferring modularity or the lack of modularity from observed patterns of developmental disorders.

Evolutionary developmental biology (“evo-devo”) may provide insights and new methods for studies of cognition and cultural evolution. For example, I propose using cultural selection and individual learning to examine constraints on cultural evolution. Modularity, the idea that traits vary independently, can facilitate evolution (increase “evolvability”), because evolution can act on one trait without disrupting another. I explore links between cognitive modularity, evolutionary modularity, and cultural evolvability. (Published Online November 9 2006).

It is becoming increasingly clear that acquiring cognitive skills is feasible only with significant developmental constraints. However, recent research provides the strongest evidence to date for constructivist development. Here, we examine how these two apparently conflicting perspectives may be reconciled. Specifically, we suggest that subcortical and cortical structures possess divergent developmental strategies, with many subcortical structures satisfying Fodor's criteria for modularity. These structures constitute an early behavioral system that guides the construction of later emerging cortical structures, for which there is little evidence for modularity. Thus, we focus on how the dynamic time course of development itself implicitly constrains the emergence of cortical representations, reducing the requirement for built-in encodings of knowledge in cortical circuits, as on the traditional nativist conception.

This commentary questions the authors’claim that cognitive neuropsychology is defined by modularity and that other theoretical frames, that is, connectionism, are a priori rejected. It also points to the fact that whereas in genetic disorders there are developmental delay and asynchrony, there are few reports of deviant developmental trajectories that are never seen in typical development. It is suggested that the possibility that structure does not equal function in the developing brain, may be a viable option.

There is an argument that has recently been deployed in favor of thinking that the mind is mostly (or even exclusively) composed of cognitive modules; an argument that draws from some ideas and concepts of evolutionary and of developmental biology. In a nutshell, the argument concludes that a mind that is massively composed of cognitive mechanisms that are cognitively modular (henceforth, c-modular) is more evolvable than a mind that is not c-modular (or that is scarcely c-modular), since a cognitive mechanism that is c-modular is likely to be biologically modular (henceforth, b-modular), and b-modular characters are more evolvable (e.g., Sperber 2002, Carruthers 2005). In evolutionary biology, the evolvability of a character in an organism is understood as the “organism’s capacity to facilitate the generation of non-lethal selectable phenotypic variation from random mutation” with respect to that character. Here I will argue that the notion of cognitive modularity needed to make this argument plausible will have to be understood in terms of the biological notion of variational independence; that is, it will have to be understood in such a way that a cognitive feature is c-modular only if few or no other morphological changes (cognitive and not) are significantly correlated with variations of that feature arising in members of the relevant population. I will also argue that all –except for (possibly) one—of the connotations contained in a cluster of notions of cognitive modularity widely accepted in some of the mainstream currents of thought in classical cognitive science, are simply irrelevant to the argument. In order to argue for this, I will have to examine the question as to whether there are any strong theoretical connections between (1) those connotations and (2) notions of modularity accepted in biology, specially in evolutionary and in developmental biology, that are thought to be most relevant to arguments to the effect that biological modularity enhances evolvability.

Evolutionary Psychology is based on the idea that the mind is a set of special purpose thinking devices or modules whose domain-specific structure is an adaptation to ancestral environments. The modular view of the mind is an uncontroversial description of the periphery of the mind, the input-output sensorimotor and affective subsystems. The novelty of EP is the claim that higher order cognitive processes also exhibit a modular structure. Autism is a primary case study here, interpreted as a developmental failure of a module devoted to social intelligence or Theory of Mind. In this article I reappraise the arguments for innate modularity of TOM and argue that they fail. TOM ability is a consequence of domain general development scaffolded by early, innately specified, sensorimotor abilities. The alleged Modularity of TOM results from interpreting the outcome of developmental failures characteristic of autism at too high a level of cognitive abstraction.

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.