5.2 Modularity and Evolutionary Psychology

In previous chapters, I noted that brains—as well as organisms in general—

are hierarchically organized structures composed of components. These

components are engaged in specialized processes that form subsystems,

and these subsystems interact with one another at various levels in the

organismic hierarchy, producing particularized and generalized homeostasis.

Also, I endorsed the idea that these processes and subsystems function

the way they do because of their role in the organization of the whole organism and the fact that they were selected for in their evolutionary

past. From these realities of the brain concerning its hierarchical organization,

specialized processing, and evolution, we can infer at least three

things about human psychology.

First, psychological states are emergent properties that are the results of

brain states; they may not be reducible to brain states, but they are certainly

dependent upon brain state processes (Baars & Newman, 2001;

Bisiach, 1999; Kim, 2000). If there is any doubt about this, one need only

peruse any textbook or journal devoted to the human brain’s workings and

read about the effects of brain damage upon the psychology of a person.

For example, without the normal functioning of the prefrontal cortex,

individuals are not able to make plans, nor are they able to carry out the

behavior necessary to fulfi ll those plans (Fuster, 1997; Passingham, 1993).

Also, as Finke (1980) has demonstrated, damage to the prefrontal cortex

causes a person to be unable to store short-term memories. Further, damage

to the limbic system can cause certain autisms and other emotional dysfunctions

(Bauman & Kemper, 1994).

Concerning my endorsement of psychological states as emergent properties

of the brain, as I stated in the third chapter, just as the components

at various levels of neurobiological and biological hierarchies—such as

organelles, cells, tissues, and organs—cannot be reduced to the physicochemical

parts of which they are composed, so too, various forms of visual

cognition, although dependent upon neurobiological processes, are not

reducible to such processes. Again, the main reason why psychological

phenomena are nonreducible to neurobiological phenomena is the same

reason why neurobiological and biological components are nonreducible

to the physicochemical parts of which they are composed, namely, such

components and phenomena emerge as a result of the way in which they

are organized to do something directly related to generalized homeostasis

of the organism. The psychological dimension associated with the brain’s

activities can be considered as another level of emergent phenomena

added to the hierarchy. This is so because cognition appears to be organized

in such a way as to aid an animal in discriminating information in

environments so as to fi ght, fl ee, feast, forage, and so forth. However, the

kind of end result or end product of cognition—although similar to other

activities in the animal’s hierarchy in having generalized homeostasis as

the goal—is different in that such a product is a psychological phenomenon

that aids in generalized homeostasis.

Second, given the localization and massive, specialized parallel processing

of the brain, we can infer that there are a variety of specialized psyScenario chological states that are dependent upon these processes as well. Damage

to certain areas of the brain yield specifi c psychological defi cits. For

example, damage to Wernicke’s area causes one to be unable to comprehend

language, damage to V5 causes one to be unable to perceive depth

accurately, and damage to the IT cortex causes one to be unable to recognize

faces. It may not be the case that all motor and cognitive abilities are

localized, but we have evidence that many neurobiological processes, and

the psychological phenomena that emerge from them, are dependent

upon specifi c areas of the brain.

Third, given that the brain is an organ, it is subject to the same evolutionary

principles as any other biological entity. The brain functions the

way it does because of fortunate genetic mutations, in combination with

environments, that occasioned its selection as a trait most fi t for the

animal. By inference, if psychological states are the results of brain states,

and brain states are subject to evolutionary principles, then it is likely

that psychological states are subject to evolutionary principles. The three

points just mentioned are signifi cant to the science of evolutionary

psychology.

All evolutionary psychologists posit that evolution is responsible not

only for human physiology and anatomy but also for certain human psychological

and behavioral characteristics that evolved in our past to solve

specifi c problems of survival (Buss, 1999; Cosmides & Tooby, 1992, 1994;

Pinker, 1994, 2002; Shettleworth, 2000; Gardner, 1993; Sternberg, 1988;

Wilson, 2003; Scher & Rauscher, 2003; Plotkin, 1997; Palmer & Palmer,

2002; also see the relevant papers in Arp & Ayala, 2008; Arp & Rosenberg,

2008). The logic here is straightforward and is consistent with the defi nition

of function as a recent evolutionary development I endorsed in the

second chapter, as well as with the evolutionary principles of genetic variability

and natural selection mentioned in the previous chapter. Traits

(e.g., organs, capacities, or behaviors) develop in evolutionary history to

function as a result of chance mutations and the natural selection of the

trait that is most fi t, given the environment in which the trait exists. For

example, eyes developed in order to see food, prey, mate, or predator;

webbed appendages developed to allow an organism to swim more effi -

ciently; and physiological systems in the body developed to serve each

specifi c end—digestion, circulation, and so forth—with the greater and

overall end of survival and reproduction. Just as other traits developed

functions in some specifi ed evolutionary history, so too, the human brain

has developed the certain functions it performs in simply reacting to the

information presented to it in an environment, as well as giving rise to a conscious feature that interprets, integrates, and makes decisions with

respect to this information.

The brain, then, is envisioned as having evolved certain psychological

modules (Fodor, 1983; Pinker, 1997, 2002), intelligences (Gardner, 1993), or

domains (Cosmides & Tooby, 1992, 1994; Hirschfeld & Gelman, 1994) that,

in the words of Cosmides & Tooby (1992, p. 34), are “specialized for solving

evolutionary long-enduring adaptive problems and . . . these mechanisms

have content-specialized representational formats, procedures, cues, and

so on.” Some of these mental modules, like those associated with rudimentary

phoneme and object recognition, are considered domain specifi c, since

they are devoted to solving one particular kind of adaptive problem. Other

modules—or possibly, just one huge module—are considered domaingeneral,

since they are devoted to solving any number of adaptive problems.

General intelligence is the term used most often to describe the

domain-general feature of the mind. According to Wheeler & Atkinson

(2001, p. 242), adaptive problems are “problems that are specifi able in terms

of evolutionary selection pressures, i.e., recurring environmental conditions

that affect, or have affected, the reproductive success of individual

organisms.” Thus, Pinker (1997, p. 27) claims that the mind “is not a single

organ but a system of organs, which we can think of as psychological faculties

or mental modules . . . intelligent behavior is learned successfully

because we have innate systems that do the learning”—such systems

having evolved to deal with adaptive problems in our early hominin

past.

These psychological modules/domains/intelligences are caused by, but

not wholly reducible to, modules or areas of the brain. Here, we must

keep in mind the distinction between a psychological or mental module

that is caused by, but not reducible to, a neurophysiological or brain-process

module or area. Thankfully, researchers will use the term area when specifi

cally referring to a neurophysiological process, as opposed to a psychological

process (Hermer & Spelke, 1996; Kaas, 1993; Karmiloff-Smith,

1992; Shallice, 1997; Bruno & Cutting, 1988).

According to evolutionary psychologists, the brain is represented as a

host of modules, some of which are located in a single area (e.g., Broca’s

area for grammar–usage), while others are dispersed over the entire cortex.

Brain-process modules can be viewed as nested within hierarchies, whereby

larger modules coordinate information from smaller modules, which

themselves coordinate information from still smaller modules, and so

forth. The what system I spoke about in the third chapter works this way.

We can think of this system as one big module made up of smaller modules; V1 is the smaller module responsible for initial visual processing,

V2 is the smaller module responsible for stereo vision, and V4 is the smaller

module responsible for color. In this way, as Marr (1983) intimates, early

vision is a distinct capital-M module made up of smaller-m modules.

It is at the higher ends of certain brain-process modular hierarchies—for

example, the dorsolateral prefrontal cortex, which integrates multimodal

sensory information and is involved in the generation of hypotheses,

planning, goal direction, and the deployment of strategies—where the

psychological modules clearly have emerged. Because of brain-process and

psychological modules interacting with environments for thousands—

perhaps even millions—of years, evolutionary psychologists think that

psychological modules specialized in their particular performances to deal

with the various challenges posed by the environments in which our

hominin ancestors lived.

In previous chapters, I noted that brains—as well as organisms in general—

are hierarchically organized structures composed of components. These

components are engaged in specialized processes that form subsystems,

and these subsystems interact with one another at various levels in the

organismic hierarchy, producing particularized and generalized homeostasis.

Also, I endorsed the idea that these processes and subsystems function

the way they do because of their role in the organization of the whole organism and the fact that they were selected for in their evolutionary

past. From these realities of the brain concerning its hierarchical organization,

specialized processing, and evolution, we can infer at least three

things about human psychology.

First, psychological states are emergent properties that are the results of

brain states; they may not be reducible to brain states, but they are certainly

dependent upon brain state processes (Baars & Newman, 2001;

Bisiach, 1999; Kim, 2000). If there is any doubt about this, one need only

peruse any textbook or journal devoted to the human brain’s workings and

read about the effects of brain damage upon the psychology of a person.

For example, without the normal functioning of the prefrontal cortex,

individuals are not able to make plans, nor are they able to carry out the

behavior necessary to fulfi ll those plans (Fuster, 1997; Passingham, 1993).

Also, as Finke (1980) has demonstrated, damage to the prefrontal cortex

causes a person to be unable to store short-term memories. Further, damage

to the limbic system can cause certain autisms and other emotional dysfunctions

(Bauman & Kemper, 1994).

Concerning my endorsement of psychological states as emergent properties

of the brain, as I stated in the third chapter, just as the components

at various levels of neurobiological and biological hierarchies—such as

organelles, cells, tissues, and organs—cannot be reduced to the physicochemical

parts of which they are composed, so too, various forms of visual

cognition, although dependent upon neurobiological processes, are not

reducible to such processes. Again, the main reason why psychological

phenomena are nonreducible to neurobiological phenomena is the same

reason why neurobiological and biological components are nonreducible

to the physicochemical parts of which they are composed, namely, such

components and phenomena emerge as a result of the way in which they

are organized to do something directly related to generalized homeostasis

of the organism. The psychological dimension associated with the brain’s

activities can be considered as another level of emergent phenomena

added to the hierarchy. This is so because cognition appears to be organized

in such a way as to aid an animal in discriminating information in

environments so as to fi ght, fl ee, feast, forage, and so forth. However, the

kind of end result or end product of cognition—although similar to other

activities in the animal’s hierarchy in having generalized homeostasis as

the goal—is different in that such a product is a psychological phenomenon

that aids in generalized homeostasis.

Second, given the localization and massive, specialized parallel processing

of the brain, we can infer that there are a variety of specialized psyScenario chological states that are dependent upon these processes as well. Damage

to certain areas of the brain yield specifi c psychological defi cits. For

example, damage to Wernicke’s area causes one to be unable to comprehend

language, damage to V5 causes one to be unable to perceive depth

accurately, and damage to the IT cortex causes one to be unable to recognize

faces. It may not be the case that all motor and cognitive abilities are

localized, but we have evidence that many neurobiological processes, and

the psychological phenomena that emerge from them, are dependent

upon specifi c areas of the brain.

Third, given that the brain is an organ, it is subject to the same evolutionary

principles as any other biological entity. The brain functions the

way it does because of fortunate genetic mutations, in combination with

environments, that occasioned its selection as a trait most fi t for the

animal. By inference, if psychological states are the results of brain states,

and brain states are subject to evolutionary principles, then it is likely

that psychological states are subject to evolutionary principles. The three

points just mentioned are signifi cant to the science of evolutionary

psychology.

All evolutionary psychologists posit that evolution is responsible not

only for human physiology and anatomy but also for certain human psychological

and behavioral characteristics that evolved in our past to solve

specifi c problems of survival (Buss, 1999; Cosmides & Tooby, 1992, 1994;

Pinker, 1994, 2002; Shettleworth, 2000; Gardner, 1993; Sternberg, 1988;

Wilson, 2003; Scher & Rauscher, 2003; Plotkin, 1997; Palmer & Palmer,

2002; also see the relevant papers in Arp & Ayala, 2008; Arp & Rosenberg,

2008). The logic here is straightforward and is consistent with the defi nition

of function as a recent evolutionary development I endorsed in the

second chapter, as well as with the evolutionary principles of genetic variability

and natural selection mentioned in the previous chapter. Traits

(e.g., organs, capacities, or behaviors) develop in evolutionary history to

function as a result of chance mutations and the natural selection of the

trait that is most fi t, given the environment in which the trait exists. For

example, eyes developed in order to see food, prey, mate, or predator;

webbed appendages developed to allow an organism to swim more effi -

ciently; and physiological systems in the body developed to serve each

specifi c end—digestion, circulation, and so forth—with the greater and

overall end of survival and reproduction. Just as other traits developed

functions in some specifi ed evolutionary history, so too, the human brain

has developed the certain functions it performs in simply reacting to the

information presented to it in an environment, as well as giving rise to a conscious feature that interprets, integrates, and makes decisions with

respect to this information.

The brain, then, is envisioned as having evolved certain psychological

modules (Fodor, 1983; Pinker, 1997, 2002), intelligences (Gardner, 1993), or

domains (Cosmides & Tooby, 1992, 1994; Hirschfeld & Gelman, 1994) that,

in the words of Cosmides & Tooby (1992, p. 34), are “specialized for solving

evolutionary long-enduring adaptive problems and . . . these mechanisms

have content-specialized representational formats, procedures, cues, and

so on.” Some of these mental modules, like those associated with rudimentary

phoneme and object recognition, are considered domain specifi c, since

they are devoted to solving one particular kind of adaptive problem. Other

modules—or possibly, just one huge module—are considered domaingeneral,

since they are devoted to solving any number of adaptive problems.

General intelligence is the term used most often to describe the

domain-general feature of the mind. According to Wheeler & Atkinson

(2001, p. 242), adaptive problems are “problems that are specifi able in terms

of evolutionary selection pressures, i.e., recurring environmental conditions

that affect, or have affected, the reproductive success of individual

organisms.” Thus, Pinker (1997, p. 27) claims that the mind “is not a single

organ but a system of organs, which we can think of as psychological faculties

or mental modules . . . intelligent behavior is learned successfully

because we have innate systems that do the learning”—such systems

having evolved to deal with adaptive problems in our early hominin

past.

These psychological modules/domains/intelligences are caused by, but

not wholly reducible to, modules or areas of the brain. Here, we must

keep in mind the distinction between a psychological or mental module

that is caused by, but not reducible to, a neurophysiological or brain-process

module or area. Thankfully, researchers will use the term area when specifi

cally referring to a neurophysiological process, as opposed to a psychological

process (Hermer & Spelke, 1996; Kaas, 1993; Karmiloff-Smith,

1992; Shallice, 1997; Bruno & Cutting, 1988).

According to evolutionary psychologists, the brain is represented as a

host of modules, some of which are located in a single area (e.g., Broca’s

area for grammar–usage), while others are dispersed over the entire cortex.

Brain-process modules can be viewed as nested within hierarchies, whereby

larger modules coordinate information from smaller modules, which

themselves coordinate information from still smaller modules, and so

forth. The what system I spoke about in the third chapter works this way.

We can think of this system as one big module made up of smaller modules; V1 is the smaller module responsible for initial visual processing,

V2 is the smaller module responsible for stereo vision, and V4 is the smaller

module responsible for color. In this way, as Marr (1983) intimates, early

vision is a distinct capital-M module made up of smaller-m modules.

It is at the higher ends of certain brain-process modular hierarchies—for

example, the dorsolateral prefrontal cortex, which integrates multimodal

sensory information and is involved in the generation of hypotheses,

planning, goal direction, and the deployment of strategies—where the

psychological modules clearly have emerged. Because of brain-process and

psychological modules interacting with environments for thousands—

perhaps even millions—of years, evolutionary psychologists think that

psychological modules specialized in their particular performances to deal

with the various challenges posed by the environments in which our

hominin ancestors lived.