Biological Background

The brain is a very expensive organ to maintain. Given the fact that the human brain is three times larger than it would be if humans were apes, we have to ask, Why and how did brain expansion occur in the human lineage? And what were the selection pressures that produced a cognitive capacity that surely far outstripped the day to day practical demands of a hunter-gatherer way of life? Whichever hypotheses proves to be correct, it require the same kind of environmental context: a stable, high-energy food supply, with minimum predation pressure. In being well endowed mentally, humans and other primates are a part of a very clear pattern among vertebrates as a whole. By being mammals, primates are therefore better equipped mentally than any reptile. the brain of Homo sapiens is three times bigger than that of an ape of the same body size.

The need to grow such a large brain has distorted several basic life-history characteristics seen in other primates. human mothers devote a relatively greater quantity of energy and other resources to fetal brain and body development over a standard time than do our closest relative, the great apes. Compared with other altricial species, the rapid postnatal phase (at a fetal rate) of brain growth continues for a relatively longer period in humans. This extension effectively gives humans the equivalent of a 21-month gestation period (9 months in the uterus, and 12 months outside). One important consequence of this secondary altriciality is that human infants are far more helpless, and for a much longer time, than the young of the great apes. This extended period of infant care and subsequent schooling must have had a major impact on the social life of hominins.

Archaeological Evidence

Two types of fossil evidence are related to brain evolution: indications of absolute size, and information about the surface features of the brain. Fossils show that brain expansion had already been established by the time Australopithecus afarensis appeared. Marked brain expansion is seen with the origin of the genus Homo. Very briefly, a brain in which the parietal and temporal lobes predominate is considered humanlike, whereas apelike brains contain much smaller parietal and temporal lobes. In addition, human frontal lobes are considerably more convoluted than in apes. If brain reorganization toward the human configuration began only with the origin of Homo, while the australopithecine brain remained essentially apelike, then it would be consistent with other events in human prehistory. Brains in modern humans are strongly lateralized, that is, in the general population the left hemisphere is larger than the right. Such lateralization is seen in early Homo. This feature is assumed to be associated with tool making and use.

The earliest stone-tool-making hominins, apparently possessed greater cognitive skills than modern chimpanzees. Apparently something changed in the brains of the earliest hominin tool makers to permit the development of this ability. One other insight into how fossil evidence might show expanding brain size, concerns the impact of brain expansion on social organization, specifically in infant care.

primates can predict the consequences of their behavior for others and they understand enough about the motives of others to be able to be capable of deceit and other subtle forms of manipulation. Researches shows that primate species with more complex social interaction have larger cerebral cortexes. individuals that are adept at building and maintaining alliances are also reproductively more successful: making alliances opens up potential mating opportunities. Once a society has reached a certain level of complexity, then new internal pressures must arise which act to increase its complexity still further. By being able to look into one’s own mind and see one’s reactions to things and other individuals, one can more precisely predict how others will react to those same things and individuals. Consciousness builds a better reality a one that is attuned to the highly social world that humans inhabit.

Some Reasoning

The whole process of thinking can be distilled into a proposition: THINKING IS PREDICTION. Thinking evolve to predict, to forecast, to imagine what is going to happen; and after that, what is going to happen “IF”. This “if” is the beginning of reasoning. This “if” gave us initiative, by forcing us to imagine all possible opportunities in the future. But in reality THERE IS NO FUTURE, future does not exist. Future, and what will happen in it, are just our mind’s models and imaginations, out of our fears, expectations and desires.

I purport that every moment that we spend in thinking, we are predicting the possible scenarios to be, in the network of present phenomena of course: “If I am not careful, my hand may overturn that cup of coffee, and its content pour on my book; so I move the cup further away.” The cup does not ruin my book, but I saw this possibility quite clear, because of my past experiences, observations and hearing. By acquiring this ability, we humans, step by step through imagination and sharing our experiences through language, prevent disastrous happenings. By that, we survive and not only survive, but mastering the possibilities in the web of present phenomena.

We use this ability extravagantly to the point that we couldn’t stop it, and take refuge in alcohol, drugs and pleasure to get rid of it for a moment. We teach this maniacal imagination to each other; we communicate through predictions. We drown in thinking. One outcome of this is to be negligent to the present, to what is real. In fact, every time that we start thinking, we lost the moment, and we always think.