Piero Scaruffi(Copyright © 2013 Piero Scaruffi | Legal restrictions )
These are excerpts and elaborations from my book "The Nature of Consciousness"
The Prehistory of Brain
In the 1940s the British anthropologist Kenneth Oakley speculated that there may be three levels of consciousness, corresponding to the three evolutionary layers of the brain: awareness, controlled by the older part of the brain and related only to conditioning; consciousness, controlled by the cortex and the hippocampus, and related to the internal representation of the world; and self-awareness, due to the most recent layer of the brain and related to the internal representation of one's internal representation.
John Eccles speculated that consciousness arose with the advent of the mammalian neocortex, about 200 million years ago, the biologist Lynn
The US paleo-neurologist Harry Jerison looked at the fossil record for clues on the selection pressures that led to increases in the size of the primate brain.
Mammals evolved about 200 million years ago as the “nocturnal” reptiles. Unlike reptiles (such as dinosaurs), whose cognitive life was based on stimulus-response, mammals were capable of using sound to create a cognitive map of their environment. When the big reptiles disappeared 70 million years ago, vision too became a major source of information for the mammal brain, which evolved accordingly. In particular, the size of the brain increased dramatically. The brain of mammals was flooded with sensory inputs, and had to develop the ability to recognize an object that could be defined by many (virtually infinitely many) different sets of inputs. The solution was to develop a way to represent the perceptual world and use that representation to recognize objects. Thus the mammalian brain developed the ability to process stimuli by means of a “conscious” perceptual world, as opposed to the reflexes of the reptilian brain.
The function of consciousness was therefore to create the perception of the object, regardless of what sets of inputs originated the recognition.
The reptilian brain was simply “reacting” to stimuli, without any awareness of what those stimuli “meant”. The mammalian brain was capable of transforming the stimuli into an “object” existing in time and space, and then “act” accordingly.
Jerison speculates that the human brain is, first and foremost, a marvel of integration. The brain is flooded with sensory data. If the brain had to analyze them one by one in isolation, it would be virtually impossible to cope with the number of sensory data. Jerison believes that the nervous system constructs a model of the world, and then uses that model to “understand” sensory data. The key to constructing the model of the world is to integrate all the sensory data themselves. As the model gets refined, it also gets easier to recognize sensory data for what they are. A sensory datum is not recognized in isolation, but it is recognized as part of a scene. That scene, in turn, represents the integration of all the data that have been perceived.
The implication is that we are conscious of something that is not necessarily the real world, but is simply the world that we created. The “world” that we perceive is nothing more than the model that we have created. That model is not necessarily the world as it is: it is a plausible model of the world, given what we have learned so far about it.
The Prehistory Of Mind
The British archeologist Steven Mithen found evidence in ancient history that "cognitive fluidity" caused the modern mind to arise.
First came social intelligence, the ability to deal with other humans; then came natural-history intelligence, the ability to deal with the environment, and tool-using intelligence; last, language. Once the ability to fully connect all these faculties developed, the modern mind was born. Crucial for the development of the human mind was language. In particular, metaphor and analogy are the fundamental features that allowed the human mind to develop as it is.
Homo Sapiens Sapiens appeared 100,000 years ago and initially behaved like Neanderthals, showing little intelligence. Two momentous transformations in human behavior occurred with art and technology (60,000 years ago) and with farming (10,000 years ago).
In order to explain these breakthroughs, Mithen resorts to Jerry Fodor's modular model of the mind. Initially, human minds were dominated by a general-purpose form of intelligence. Then a module appeared that was specialized for socializing. The social-intelligence module was shared with other primates so it must have predated humans. Then other modules, each specific to one domain, were born around the main general-purpose module. The modules evolved separately. Eventually, Mithen admits four types of intelligence (four modules in the mind): social, technical (tool-making, house building), natural-history (e.g., animal behavior) and linguistic. These modules were not connected, these “intelligences” were not communicating.
Mithen can thus explain why there is no archeological evidence of social life when (judging from brain size) social intelligence must have been already quite developed: a cognitive barrier between social and technical intelligence made it impossible for humans to conceive of tools for social interaction. Originally, humans were hunters and gatherers (the transition to farming occurred in the Middle East only about 10,000 years ago). The hunter-gatherers of our pre-history were experts in many domains, but those different kinds of expertise did not mix, precisely because the minds of those humans could not mix different types of intelligence.
"Cognitive fluidity" (mixing different kinds of intelligence) changed that and caused the cultural explosion of art, technology, religion. Suddenly, humans acquired minds in which modules had been connected. For example, tools started being used to transform nature. Religion was a by-product of mixing these intelligences, because mixing intelligences one can produce supernatural beings.
Farming was also a product of cognitive fluidity and in turn caused a redefining of intelligences (emergence of new intelligences, disappearance of old ones).
The factor that contributed or caused cognitive fluidity may have been the dawning of consciousness. Self-awareness may have integrated intelligences that for thousands of years had been kept separate.
Mithen's evolutionary theory mirrors in many ways the theory of child development advanced by British psychologist Annette Karmiloff-Smith.
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