Evolution of Intelligence - Shepard essay #2

Continuing with Shepard, today's speculations on the essay On Animal Thinking traces the evolution of intelligence and addresses the anthropocentric tendency to see human intelligence as seperate from the rest of existence. His thesis is that "Progressive intelligence is the evolutionary sharpening of mind due to the interplay between animals." (Shepard, 28) He begins by pointing out that modern life is increasingly devoid of wild animals. A major aspect of Shepard's thinking is that animals play a large role in the ontogeny (development after birth) of human beings. He argues convincingly elsewhere that animals play a role in "...the shaping of personality, identity, and social consciousness" but that is not the main topic of this piece. (Shepard, 22) Its just the presupposition he states to give relevance to the argument to come.

Along with the presupposition noted above, Shepard offers an alternative to the view of evolution as a hierarchical process leading the pinnacle of human intelligence. This flawed notion of transcendent humanity leaves us viewing the others (rest of life on earth) with resentment. The alternative to this ingrained notion is that mind is universal, expressing itself in many forms. Human intelligence emerged from a framework of organs and mechanisms we share with other creatures.

Shepard traces this framework back to flowering plants and insects, whose interaction created the literal ground from which the mammalian mind evolved. This symbiotic relationship (plants as food, insects as pollinators) gave earth the layer of organic soil that is the basis for the complex ecological arrangements to follow. It also produced the nutritious seeds needed for larger life forms to evolve. The diversity of plants is the primary factor in the diversity of ecosystems, the complex nervous systems of later creatures has its basis in the complexity of plant/insect communities. Shepard lists five types of intelligence found in the world at the time of primate evolution. First is the insect, characterized by instinctual behavior based on fine tuned sensory apparati and hive social activity. Second is birds, who possess integrated audio/visual systems. Third and fourth are large predator and prey mammals, and Fourth is primate intelligence. We discussed yesterday how primate intel developed in tropical jungles, but today we will concentrate on the hominid habitat of grasslands and the large mammal predator/prey bond.

The evolution of large mammals and large brains took place most dramatically on grasslands, because there was plenty of available energy to exploit in this ecosystem. Grasslands produce very rich soil which creates plants with plentiful yields of high protein seeds, grain, and vegetable matter readily available for digestion (as opposed forests of trees which require fungi and bacteria to slowly break down woody indigestible matter). Initially brain size increased only to accommodate larger body size. At some point a specialized adaptation of the brain began in carnivores who developed hunting skills like tracking, stalking, and group coordination. Before this they had followed innate reflex, now they used "....combined sensory modalities, memory, experience, and skill." (Shepard, 31)

As predators evolved killed hunting, the pressure of natural selection produced elaborate escaped tactics in herbivore prey such as utilizing geography for protection, acting as decoy to protect most vulnerable, group defensive maneuvering. The result of this is an "....upward spiralling of intelligence..." (Shepard, 32) From our perspective this selection for intel seems an inevitable progression, but there are costs. More brains requires more food and a longer period of infant dependency, and instincts are sometimes better suited than more complex thinking. Only 5 of 20 mammalian orders have gone this route (primates, marine mammals, even and odd toed herbivores, and carnivores). Shepard believes that the number of species with specialized thinking is limited by the number of smaller brained creatures in an ecosystem, a ratio of sorts.

We now concentrate on the type of intelligence found in this predator/prey adaptation. It is defined by a vigilant awareness, an attention to sensory details. The mind places stimulus in the context of past experience, and can cause arousal Arousal in prey releases fear-inducing adrenaline. Arousal in predator releases norepinephrine which causes aggression. This leads us to the omnivores, our selves included, who combine aspects of both mentalities; the cunning of predator and the caution of prey. To find what distinguishes us from other omnivores we need to look at how primates evolved out of nocturnal mammals.

Nocturnal mammals developed heightened hearing and smelling abilities, which were integrated in the mind, forming awareness of time and space (where did that sound or smell come form?When did it occur in relation to other sounds and smells?). This process is known as the "...encephalization...of tissues for storing information" and is characterized by the ability to perceive patterns and create order out of sensory inputs. (Shepard, 39) When this hardware is placed in the context of diurnal arboreal mammals, images could likewise be stored and placed in a spatial/temporal context. This allows the ability to perceive past (recalling image) and future (prediction based on experience), making human consciousness dependent on particular brain adaptations and function that precede primates. Evolution is not as straight forward as it is commonly understood, it involved rewiring older adaptations for new purposes.