An Introduction to Renewed Darwinian Theory of Human Behavior

The Renewed Darwinian (RD) theory of human behavior is a synthesis of the current contributions of all the disciplines shown in the figure  below. The RD theory is built on the foundation of Darwin’s insights about human behavior that he articulated in The Descent of Man. These insights about humans have been largely neglected since Darwin’s time probably because of the overwhelming scope of his theory of natural selection about all life that he set forth in his masterpiece, The Origin of Species.

A fragmentation of the sciences of human behavior occurred around the time of Darwin’s death. Each emerging discipline has, since that time, been pursuing its own agenda with relatively little effort addressed to the development of an integrated scientific theory of human behavior. A wide variety of theories have been developed by the ‘soft’ behavioral disciplines of economics, sociology, psychology and cultural anthropology. But these disciplines have had few methodological tools with which to give their theories the ‘hard’ tests available to the physical sciences. Meanwhile a cluster of other disciplines, archeology, paleontology, physical anthropology and primatology, were steadily developing an understanding of the deep history of the Homo sapiens and predecessor species.

Now the emerging sciences of neuroscience and genomics have provided scientific tools, primarily brain scanning and genetic analysis, that can provide hard tests for the great array of theories that have been developed by the behavioral sciences. These same methods can also serve to test Darwin’s own neglected theories about humans. The new sub-fields of evolutionary psychology and behavioral economics have used these newer tools to start the integrative process, primarily by linking psychology and economics via human biology. The RD theory builds on this recent work in its attempt to draw contributions from all the relevant disciplines into a more unified Renewed Darwinian theory of human behavior.

I will sketch out below some of this theory’s major points. In essence it is a theory about how the human brain makes decisions in regard to all aspects of our lives; in our personal lives, in our face-to-face communities and in our lives in larger scale institutions and societies. It explains how the human brain with this capacity for complex decision making could have evolved from earlier hominid forms by Darwinian mechanisms. The theory offers its own explanation of such hard-to-explain phenomena as ‘free’ will,  morality, conscience, self concept, and consciousness. It provides a lens for interpreting the evolution of basic human institutions in historic times and a set of implications, guidelines for moving forward as a species. The theory cannot be faulted for lack of ambition.

Now for a few key points on how the theory proposes that the human brain works. The theory starts by recasting our understanding of unconscious drives, a task first undertaken by Freud and James. RD theory posits four basic drives, ultimate motives that underlie all human decisions. They are the two ancient ones shared by all animals with some capacity to sense and evaluate its surroundings; the drive to acquire (dA) life-sustaining resources, and the drive to defend (dD) from all life-threatening entities. The two newer drives, that evolved to an independent status in humans, are the drive to bond (dB) in long-term  mutually caring relationships with other humans, and the drive to comprehend (dC), to make sense of the world around us in terms of its multifaceted relations to ourselves. The “independent status” of these two drives means that they are treated as ends themselves and rewarded by the brain & nervous system in the same manner as the dA or dD.

Unsurprisingly, the four independent drives are frequently in conflict with each other in everyday life as we struggle to decide how to behave, how to respond to the immediate circumstances we face. This condition of drive-conflict brings our unique pre-frontal cortex (PFC)(link), into action. This is where our thoughts enter the bright light of higher-level consciousness. Thus, when our immediate environment, as signaled by our sense organs, is evaluated by the drive modules as presenting conflicting opportunities and hazards in terms of fulfilling the four drives, these signals are sent to our PFC. This part of the brain, when faced with drive-conflict, has the capacity to call on all the resources of the rest of the cortex to search for a response that satisfices all four drives. The resources the rest of the cortex can supply are amazing. They are all the different aspects of our cognitive brain. They are the multiple skills that we have inherited and also elaborated and honed with culturally-carried techniques, as well as with remembered personal experiences.  

Our language skills are a primary example. These elements offer a vast storehouse of alternative ways to respond to the here-and-now that the PFC juggles and analyzes to generate action options. The alternative action scenarios are recycled to the drive modules to be reevaluated until reasonable, pragmatic action plans are chosen for execution. This complex decision process is what provides humans with our unique capacity to be so flexible, so highly adaptive to all kinds of complex and varied circumstances. For, as Darwin said long ago, “It is not the strongest of the species that survives, nor the most intelligent. It is the one most adaptable to change.”

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