The Modularity of the Human Mind

A basic assumption regarding the three modalities described in this chapter is that experiences can and frequently are encoded in memory using all three modalities. That is, experiences are stored or encoded as three dimensional "packets." This modularity assumption is quite consistent with current brain theory. Anderson (1995) refers to these modular encoding of experience as "records." The concept that the brain has a modular structure has received a great deal of attention over the last two decades. Gazzaniga (1985) describes the modularity of the brain in the following way:

By modularity, I mean that the brain is organized into relatively independent functioning units that work in parallel. The mind is not an indivisible whole operating in a single way to solve all problems . . . the vast and rich information impinging on our brain is broken into parts . . . (p. 4) In his book The Modular Brain (1994), Richard Restak details the historical development of the concept of brain modularity, noting that over time it replaced the theory that the brain has a strict hierarchic organization. Restak credits Johns Hopkins neuroscientist  Vernon Mountcastle as the primary architect of the modern modular theory. He cites Mountcastle as saying:

. . . Most people don’t think hierarchically anymore; they shy away from saying "This function resides here." Instead, we now believe the brain is arranged according to a distributed system composed of large numbers of modular elements linked together. That means the information flow through such a system may follow a number of different pathways, and the dominance of one path or another is a dynamic and changing property of the system. (Restak, 1994, p. 35) 

The discussion of modularity by Restak, Mountcastle, and Gazzaniga addresses the physical architecture of the brain. Here I refer to the psychological structure of the mind & the structure of stored experience. As discussed previously, a basic assumption of the theory presented in this book is that human experiences are stored in three dimensional modules. For example, if a person goes to a football game, the experience will be encoded as mental pictures, smells, tastes, sounds, and kinesthetic sensations & all forms of non linguistic representation. The individual might also store emotions associated with the game such as anger or joy & forms of the affective modality. Finally, the individual will encode the experience as deep-structure propositions describing what occurred & forms of the linguistic modality. Some psychologists believe that, over time, the linguistic modality becomes the dominant mode of processing. "The behaviors that these separate systems emit are monitored by the one system we come to use more and more, namely the verbal natural language system" (Gazzaniga and LeDoux, 1978, p. 150). The primacy of language was demonstrated in a study by Mandler and Ritchey (1977). Subjects were shown ten pictures, one right after another. Pictures contained fairly common scenes like a teacher at a blackboard with a student working at a desk. After viewing eight such pictures for ten seconds each, subjects were presented with a series of pictures and asked to identify which ones they had seen. The series contained the exact pictures they had studied as well as distraction pictures. Two types of distractors were used, token distractors and semantic changes. Token distractor pictures changed details of the target pictures like the pattern in the teacher’s dress. Pictures that contained semantic changes altered some element that was at a high level of importance in terms of the propositional network representing the picture. For example, a semantic change might change the teacher from a male to a female. There was no systematic difference in the amount of physical change in the pictures between token changes and semantic changes. Subjects recognized the original pictures 77 percent of the time, rejected the token distractors only 60 percent of the time, but rejected the semantic distractors 94 percent of the time. In short, subjects had encoded each picture as a linguistically-based set of abstract propositions with an accompanying visual representation. It was the propositional changes in the picture that were best recognized, not the changes in the nonlinguistic aspects of the information.

Conversely, arguments are also made that the emotional system is the primary representational modality. Specifically, a good case can be made for the assertion that the affective modality exerts the most influence over human thought and experience. This case is well articulated in LeDoux’s The Emotional Brain: The Mysterious Underpinnings of Emotional Life (1996). Among other things, as a result of his analysis of the research on emotions, LeDoux concludes that human beings 1) have little direct control over their emotional reactions, and 2) once emotions occur, they become powerful motivators of future behavior. Relative to humans’ lack of control over emotions LeDoux notes:

Anyone who has tried to fake an emotion, or who has been the recipient of a faked one, knows all too well the futility of the attempt. While conscious control over emotions is weak, emotions can flood consciousness. This is so because the wiring of the brain at this point in our evolutionary history is such that connections from the emotional systems to the cognitive systems are stronger than connections from the cognitive systems to the emotional systems. (p. 19)

Relative to the power of emotions once they occur, Le Doux explains:

They chart the course of moment-to-moment action as well as set the sails toward long-term achievements. But our emotions can also get us into trouble. When fear becomes anxiety, desire gives way to greed, or annoyance turns to anger, anger to hatred, friendship to envy, love to obsession, or pleasure to addiction, our emotions start working against us. Mental health is maintained by emotional hygiene, and mental problems, to a large extent, reflect a breakdown of emotional order. Emotions can have both useful and pathological consequences. (pp. 19-20) For LeDoux, then, emotions are primary motivators that often outstrip an individual’s system of values and beliefs relative to their influence on human behavior. This was demonstrated in a study by Nisbett and Wilson (1977) who found that people are often mistaken about internal causes of their actions and feelings. The researchers noted that individuals always provide reasons for their actions. However, when reasoned and plausible reasons are not available, people make up reasons and believe them. As described by LeDoux, this illustrates that the forces that drive human behavior cannot be attributed to the rational conclusions generated by our linguistic mind, but are functions of the inner workings of our emotional mind.