The recently discovered “UNERTAN SYNDROME” consists of quadrupedal gait, severe mental retardation, and primitive language. This syndrome can be considered as devolution of human being, throwing a light into the transition from quadrupedality to bipedality with co-evolution of human mind. The genetic nature of this syndrome supports the punctuated evolution during transition from quadrupedality to bipedality. In light of Tan’s psychomotor theory, accentuating the major role of the motor system in human mind, a new theory was suggested for the human evolution. Namely, the unique behavioral trait of man, the emergence of the habitual bipedality with Homo erectus (1.6 million and 250.000 tears ago) may be coupled with a resistive mind, which forced man to stand up against the gravitational forces with consequent success in tool making and hunting, using free hands for survival. The second stage in the evolution of modern human beings may be coupled with the emergence of language (circa 40.000 years ago), playing a major role in the origins of human mind.

evolution, quadrupedality, mind, motor system, extensor muscle, human