Los cerebros por venir.
Aunque la evolución cerebral humana simula haberse detenido, es posible visibilizar su continua evolución si realizamos abstracciones y mediciones. a) En principio existe la posibilidad de liberar al cerebro a temprana edad de su calota craneana, a fin de facilitar una mayor expansión. b) Asimismo, si se lograran implementar sistemas neoténicos humanos (detención prolongada de la adolescencia), se lograrían aprendizajes más extensos, con lo que a la larga se promoverian cerebros más grandes o,mas arborizados. c) Finalmente, podria promoverse un mayor enterramiento de los pliegues cerebrales, si se somete a ciertos hombres a estreses continuos (deportes de alto riesgo, oficios y profesiones riesgosas, altamente remuneradas, etc), como aquellas en las que se tenga una sola posibilidad de salir con vida.
The brains to come.
We know that the first Homo habilis - vigorous homínids, early forgers of líthics utensils -, that inhabited Africa, between the 2,9-1,6 million years (Ma), a.C., exhibited in average: 654 cm3 of craneal capacity, a smallness in comparison to the present 1500 cm3, so that the cerebral evolution continues,it does not admit doubts.
For Christopher Ruff and collaborator, the increase of the cerebral size of the Homo sort, occurred in two stages: 1) an extremely slow one, that went from the Homo habilis to the first african Homo ergaster (1,8-0,6 Ma), with its 900 cm3 of craneal capacity. The main stimulus for the cerebral growth in this stage, was the pressing necessity to have effective prensils hands, stereoscopic vision and adjustment to dense arboreal habitát and 2)another faster and remarkable which went from 600 000 (it includes brain of Neardentales), to the 150 000 years a.C.(emergence of Homo sapiens sapiens), in which cerebral growth reached 1800 cm3. Agreed with the same Ruff, the Neardentales got to have great brains, and also got to measure a 30%, more than the present men. The great size of its brains is supposed to be developed during its migrations by cold areas and of greater latitude.
However other causal hypotheses exist that explain the increase of the cerebral size. So we knows that certain primates, derive an important amount of corporal energy, to its cerebral requirements. That is to say, promoting high metabolic demands, great brains are obtained, which accessoryly requires of diets of greater quality (animal meat). Aiello and Martin are the propulsive of the hypothesis of the "tissue of elevated cost", that is to say, high cerebral metabolic rate, to expenses of a concomitant reduction of the intestinal metabolic rate.
Although human the cerebral evolution simulates to have prisoner, it is possible to see its continuous evolution if we made abstractions and measurements. a) In principle the possibility exists of releasing to the brain at an early age of its craneal bone vault, in order to facilitate a greater expansion. b) Also, if they were managed to implement human neoténics systems (prolonged halting of the adolescence), more extensive learnings, with which in the long run brains greater or, but arborized would be obtained. c) Finally, it would be possible to promote a greater brain size if some persons are put under certain continuous stresses (sports of high risk, offices and risky professions, highly remunerated, etc), like those in which a single possibility is had of leaving with life.
The previous reflections, I hope serve as introduction, to the interesting study of Lahn and collaborator http://www.genes.uchicago.edu/fri/lahnres.html, which appeared yesterday in the NYorkTimes, that maintains that human cerebral evolution continues, showing the identified and mapping emergency (in the last 60 000 years), of two alelles: the microcephaline and the ASPM, related to increases and decrements of the cerebral size. Of another side, the found different frequencies for these two alelles, in all the world, suggests that stresses that fomented the cerebral development, were different according to habitáts and different challenges that our ancestors had to face.
As I indicate in my article: "Human brains and computers. Bio-inorganic Coevolutión ".01/30/05, the cerebral evolution has not stopped. The present cerebral evolution, is enriched by the pressures and challenges of the modern society. I suspect that in the outpost of this evolution the brains of certain: top sport human groups1 , great industralists, boss of the Mafia or, top criminals, lead politics, leaders of different die, scientifics, musicians, all kind of creators, etc. However a very numerous special human group exists, that are in accelerated form more than the others, implementing its cerebral evolution, they are the children who practice tthe different types of videogames. Like the videogames, demand high concentration, they implanted in the children very fast different automatizations, reflexes: eye hand, etc.See my articlee "Prohibited Games".07/27/05.
In these human groups, they are estan unconsciously making at the moment a series of cerebral adaptations. In the course of several generations one hopes that these adaptations will be transformed into permanent geneticos changes (generation of new aleles). However, this time the cerebral evolutionary changes will not need 60 000 years. This time will be enough 2000 or 3000 years, to much. The futurist tendency is to have greater brains, few teeth, very great eyes and extremely fine hands and feet. So, as we are losing molars by lack of use, so maybe more ahead and by necessity, we will add at our hands 1 or, 2 fingers (natural or artificial).