The Elements of Evolution (62) Propelling Human Evolution

Propelling Human Evolution

There is a universal human nature. This universality exists primarily at the level of evolved psychological mechanisms, not of expressed cultural behaviors. ~ American psychologist Leda Cosmides, American anthropologist John Tooby, & Canadian anthropologist Jerome Barkow

Volatile climate greatly affected human descent, notably African aridity and the consequent foraging demands it put upon the genus.

Homo evolved against a background of long periods of habitat unpredictability that were superimposed on the underlying aridity trend. Key factors to the success and expansion of the genus rested on dietary flexibility in unpredictable environments, which, along with cooperative breeding and flexibility in development, allowed range expansion and reduced mortality risks. ~ Susan Antón, Richard Potts, & Leslie Aiello

Major shifts in African climate coincide with 2 moments on the hominin ancestral path, roughly a million years apart, that mark significant changes in our family tree. The 1st evolutionary shake-up happened between 2.9 million and 2.4 million years ago. The 2nd shake-up occurred between 1.9 million and 1.6 million years ago. ~ American geographic environmentalist Peter deMenocal

As with other organisms, viruses propelled hominin evolution. ~30% of adaptive amino acid changes in human proteins came as viral contributions. The human inclination towards addiction via enhanced pleasure stimulation was a viral implant.

There were also other powerful forces at work, including adaptations driven by the mind: sociality and technology. Stone implements chronicle hominins as inveterate tinkerers. This exercise doubtlessly both reflected and impacted mental and social evolution.

Artifacts only hint at the evolution of hominid minds. Insights into hominin mental descent may be gleaned by comparing humans to apes, where there are slight but telling differences.

The working memory of chimps outperforms humans. Superior memory withstanding, humans are better at mental visualization, such as seeing in the mind how objects may align. Nonhuman primates rely more upon haptic contact for problem-solving related to object manipulation. The human skill of using sight rather than touch facilitates tool construction and use. Children develop this ability at 3 years of age.

Many nuanced accounts of human evolution implicitly assume that biological changes must precede cultural changes. This prevailing logic in the field may put the cart before the horse. Take care to distinguish cause from effect. Supposedly momentous changes in our genome may sometimes be a consequence of cultural innovation. ~ English geneticist Simon Fisher