Biology 202

2006 Book Commentaries

On Serendip

In the Origins of the Modern Mind, Merlin Donald explains the evolution of modern human mental capabilities as the evolution of increasingly complex memory storage systems. Professor Grobstein, in Neurobiology and Behavior, guided the class through several properties useful for understanding the brain and its role in behavior, concluding with the role and limitations of the I-function, the part of our brain of which we are aware and identify as our selves. Both concepts--memory and I-function--arose from specific observations of the nervous system. Both the book and the class recognize that memory and the I-function are interdependent, delocalized properties, but neither had enough pages or time to connect the two, especially since no one completely understands their relationship.

Origins integrates biological, anthropological, archeological and linguistic findings to propose a series of stages that, given the restraints of evolutionary theory and our knowledge of early hominids, could have led to modern human mental abilities. Each step must be evolutionarily advantageous compared to the previous stage and fit the available archeological and biological time frames. Furthermore, Donald postulates that human cognitive evolution was driven first by increasing group size, specifically social skills, and then by the need to compete against other group members.

To explain current human cognition, Donald proposes four major evolutionary stages. The first stage, episodic culture, is similar to the cognitive capabilities and resultant culture (loosely meaning the set of behaviors held by a group of animals) found in our closest living primate relatives. Great apes and early human ancestors can perceive events made up of complex stimuli and demonstrate the beginnings of self-awareness. Following episodic culture, Donald infers mimetic culture around the time of the missing link. Mimetic skill, the "ability to produce conscious, self-initiated representational acts that are intentional, but not linguistic" (p. 168), is an evolutionary step beyond episodic culture and a foundation for symbolic representation and language.

In contrast, mythic culture requires the use of symbols and mental models, which eventually led to spoken language, but may have first been manifested in gesture. However, language and gesture are not the important adaptations; rather they indicate a change within the brain for symbol use. Communication, mental modeling and complex problem solving are all possible without language. Finally, Donald suggests that theoretic culture, the most recent stage, results from "visiographic invention," the ability to symbolically store memories outside the brain. Writing systems, according to Donald, allow humans to rework models and arguments, a task biologically limited by working memory. Furthermore written language relocates memory, making external symbolic thought available to all who can interpret the symbols.

Because we have an incomplete understanding of the brain and can not know exactly how earlier human species thought, Donald can only fill in the gaps between what we think we know about our brains now and our assumed origins. He uses as much evidence as possible to support his hypothesis and grounds speculation in evolutionary theory. In spite of the inherent uncertainty, the distinction between episodic and mimetic/mythic culture fits neatly with the distinction between procedural and declarative memories that exist within modern human brains. The evolution of the brain provides a biological foundation for learning, cultural evolution, and the passing of knowledge and skills of groups through generations outside of genetic inheritance. This distinction between humans and other animals matches what we intuitively feel.

While most of the conclusions are convincing, Donald's idea of "theoretic culture" is troublesome. The quantitative increase in memory storage from external storage is an interesting and valid point, as is the quantitative increase in the transmission of ideas. However, if the brain can process theory from written language, then preliterate brains of the same species should be equally prepared for theory. The explanation of how preliterate societies are qualitatively different from literate societies is not thorough enough to make the distinction between "myth" and "theory" anything more than ethnocentrism.

The evolution of cognition detailed in Origins highlights some of the same themes covered in Neurobiology and Behavior. First, multiple approaches are necessary for studying the brain and behavior. In Bio 202, we looked at brain morphology, in-class experiments, personal experiences, and quantitative studies. Origins draws its conclusion from fossil and archeological evidence, studies of living primates, every-day human language use, and human brain "abnormalities". Diverse approaches provide a more complete view of complex systems and interactions, difficult to study directly. Donald's emphasis on social interaction skills driving evolution agrees with our framework for experience and behavior cyclically affecting and being affected by the brain. Both the class and the book refuse to look at social and biological factors separately because they are constantly interacting.

Still, the book was more concerned with evolution. In class we talked about the difference between evolution and engineering, but did not emphasize evolution as the driving force behind change nor detail brain evolution explicitly. Additionally, Origins emphasizes memory storage through symbolic modeling systems, which is something that we did not spend as much time on in class. We discussed some aspects of language, but spent little time on memory. We talked about the existence and possible formation through learning of central pattern generators, which are in some ways complex procedural memories, but did not discuss how declarative memories would work. Instead, the class focused much more on the I-function and the sense of self. While the book mentions self-awareness, it is not the emphasis or the target of explanation. Both the I-function and symbolic memory storage are decentralized, interdependent, and interacting properties.

Origins of the Modern Mind examines formalized western education within theoretic culture. Within Donald's analysis, Neurobiology and Behavior is a perfect example of creating theories (stories) to aid social interaction and competition in society. Furthermore the process of story telling and checking stories is similar to Donald's idea of theoretic culture as an opportunity to rework and compare models. Within the framework of the class, the book acts as story (theory) of the brain and behavior from another box (Donald's brain). The book provides another angle for examining the brain and behavior, but the challenge left for the book and the class together would be to relate the concluding stories of both-I function and symbolic memory storage- biologically and behaviorally (possibly through working memory?).


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