Abstract
There is overwhelming archeological and genetic evidence that modern speech apparatus was acquired by hominins by 600,000 years ago. There is also widespread agreement that behavioral modernity arose around 100,000 years ago. We attempted to answer three crucial questions: (1) what triggered the acquisition of behavioral modernity 100,000 years ago, (2) why there was a long gap between acquisition of modern speech apparatus and behavioral modernity, and (3) what role language might have played in the process. We conclude that the communication system of hominins prior to 100,000 years ago was finite and not-recursive. It may have had thousands of words but was lacking flexible syntax, spatial prepositions, verb tenses, and other features that enable modern recursive language to communicate an infinite number of ideas. We argue that a synergistic confluence of a genetic mutation that dramatically slowed down the prefrontal cortex (PFC) development in monozygotic twins and their spontaneous invention of recursive elements of language, such as spatial prepositions 100,000 years ago resulted in acquisition of special type of PFC-driven constructive imagination (called mental synthesis) and converted the finite communication system of their parents into infinite recursive language.