Comparison of the developmental stages experienced by both primates and humans has provided invaluable information regarding the evolution of both species. This information has allowed anthropologists and biologists to understand how humans successfully combined the features brought on by neoteny such as extended childhood, delayed reproduction capability, short duration breastfeeding, and adolescent growth spurt to contribute toward their survival.
One of the most obvious similarities between primates and humans is their development of a period of juvenile growth and behavior between infancy and adulthood. Although this period is greatly extended in humans, primates, like most other highly social mammals, such as wolves, dogs, and elephants postpone puberty and insert this juvenile period. Such period provides offspring with additional time to learn life skills from their parents and thereby be better prepared for life as an adult. During this period in both primates and humans, the juveniles are capable of limited self sufficiency but remain dependent on their parents for protection and, on occasion, feeding. In the juvenile period both primates and humans enjoy an acceleration in soft tissue growth. This growth contributes to both species becoming stronger during this period and increasing their agility. One of the divergences that distinguish the two species also occurs at this point as humans also enjoy rapid bone growth while the primate bone growth is much less significant. Primates and humans also demonstrate a pattern of brain growth...
These similarities include the formation of forelimbs from buds, gill slits, and other anatomical features. It is not until the very latest stages of fetal development that primates and humans begin to demonstrate any significant differences. This is consistent with the general theory that the more similar a species is to each other the longer differences begin to manifest themselves in the fetal stage. Until shortly before birth there is little difference between the development of the primates and humans which is a strong indication of their evolutionary connection.
The nuances of human development can be quite confusing. To the practical mind it does not make sense that humans actually gained on the survival scale by not developing certain abilities but the process of neoteny demonstrates that this is precisely what occurred. While the primates were shortening their own period of maturation among their offspring humans were extending it. The result was that humans became adaptive to the more complex society that they were developing while the primates became stalled in their development.
References
Bjorklund, D.F. (1997). The Role of Immaturity in Human Development. Psychological Bulletin, 153-169.
Boyd, R. (2009). How Humans Evolved. New York: W.W. Norton & Company.
Human Development
