Environmental Contributions to Human Intelligent Development in Early Stage of LifeGeneral intelligence is cognitive ability to learn novel knowledge and skills. It is an important trait for people to achieve educational and occupational success, to maintain social stability and mental and physical health in everyday life. There have been longitudinal studies suggest that intelligence difference highly associate with the genetic causes and environmental contributions1. Some cognitive traits and disorders seem heritable which led some researchers to believe that human intelligence is determined by genetic factors, but understanding of the genetic determinants of variations in intelligence is very uninformative. There is no statistically significant result that shows a single gene or a set of genes are for intelligence2. Genetic influences in general intelligence across life course are also very difficult to replicated. Until now, increasing numbers of studies have suggested that environmental factors have longitudinal impacts on the early human intelligent development3.Environmental influence during prenatal and infancyHuman cognitive development begins from the moment of conception and continues to the moment of natural end. During each stage, body constantly interacts with environmental influence and inevitably changes individual’s cognitive ability. In the prenatal period, mothers experience maternal stress during pregnancy could lead individual’s reading and cognitive disability in childhood4. Child previously exposed to synthetic stress hormone during the prenatal period also showed long-term memory impairment5. During infancy, breastfeeding has long believed that it reduces child mortality and improves child’s immunity. More evidences in recent research showed that breastfeeding does not only have multiple short-term benefits, but also has positive a long-term consequence in the adulthood6. A study conducted in Brazil over thirty years was demonstrated that participants who was breastfed for 12 months or more on average achieved higher IQ score, more years of education, higher monthly income than breastfed for 1 month or less in their adulthood7. Socioeconomic and family impacts on Childhood Social inequity leads to socioeconomic difference which in turn has latent influences on child intelligence growth. One of studies showed IQ in low socioeconomic status (SES) children was differ on average by 6 points from higher SES children in infancy, and the difference in IQ score dramatically increased by triple time at age 168. There are some studies focused on more deep understanding of changes in brain structure along childhood demonstrated SES disparities is linked to age-related cortical thickness which has been believed to contribute to child’s reading development9.ConclusionThe finding on the interactions between environmental factors and intelligence growth described above suggest that early stage of life is more critical for cognitive development. Although there is less agreement on which environmental influences play more significant role in early human intelligence development, it is reasonable to conclude that a list of environmental factors and a set of interactions between genetic environmental factors are involved.