The rapidity of Evolution of human brain as highlighted by the H.Hughes med institute team can be considered as perfectly coinciding with the origin, expansion and diversification of human civilisation. The bipedal posture freed man’s upper limbs, which were put to innumerable uses; the opposable thumb (thanx to the “opponens policis” muscle) gave greater dexterity to the upper limbs. The use of instruments led to safe handling of mankind’s greatest weapon- FIRE. Agricultural practices soon emerged parallel to hunting/gathering.
When survival became highly dependent on “cooperation”, collective practices which later became unwritten codes emerged. This is what we call Civilization.
The “selfish gene” soon shifted its strategies to suit this “culture” thingy. Altruism, which comprises of qualities like “selflessness”, “mutual respect”, “sacrificing for the good of community”, soon became a fad. There is evidence to say that primitive forms of this strategy of “altruism” appeared very early in social animals like insects. Still then, we can confidently say that “altruism” was strongly bound to “culture” with the emergence of Civilisation.
It’s a well known fact that the thalamo-limbic systems along with the basal ganglia constitute the evolutionarily primitive parts of the mammalian brain. The upper most parts especially the cortical regions are phylogenetically recent expansions. The emergence of altruistic traits might have led to emergence of cortical areas, since these areas deal with the faculties of “social behaviour”, “emotional restrain”, “language” etc. also b’coz, the predominant function of these areas is to exert inhibitory effects on “impulsive behaviour” of the thalamo-limbic system.
Primitive modes of communication thru calls & grunts must have given way to advanced “spoken language”. And this offered a whole universe of possibilities…especially, propagation of ideas and ideology…
Thus you can see that all of this is interconnected and everything including marriage and sex can be viewed in this context as derivatives of these “cerebral faculties”. All these cultural developments were within small time frames, so were their genotypic parallels, according to Lahn. The past few decades of human history also proves this hypothesis: sects of humans that made the use of electronic gadgets a part of their culture have seen unbelievable expansions in the IQ of their general populations. Their children are exposed to quests of life that demand better intelligence- computers, calculators, home appliances, video games, intellectual exercises, problem solving etc…at an earlier age. When such pursuits become essentiality it may get embedded in genes too…an example of this kind is the genetic basis of religiosity.
The second aspect of this discovery is about a long forgotten concept put forth by Gould and Eldredge. It’s the concept of SPANDRELS. Literally it refers to the empty space enclosed in the arches and domes of Churches and mosques. Gould assumed that many of the complex organs in animals/ plants as analogous to these spaces, and gave the example of the empty space inside the shell of sea animals. They give nature an opportunity to be modified in a wide variety of ways. Human brain and its faculties may also be thought of as result of modified “spandrels”. For example, it’s difficult to find an evolutionary explanation for “arithmetic” abilities or “musical” ability or “artistic” faculty.
What sort of selection pressures might have resulted in such faculties..?
It’s almost improbable that an environment that particularly favoured Art or Music or Arithmetic abilities might ever have existed in human or animal history. To survive in nature you needn’t be an artist or a singer or a mathematician…it becomes clearer when u think more about it.
That means, these qualities didn’t rise out of natures pressures for a better brain…but rather, they were modifications on some other “not-previously-explored” parts or faculties of the brain. The startling discovery that spoken language is NOT simply an extension of primitive modes of animal communication, points to the above fact. It is therefore highly likely that natural selection might have tinkered with previously dormant areas of the brain to “create” intelligent minds out of animal brains.