Quantitative Research Synthesis Essay

Intelligence based functioning is one of the most powerful forces that influences all areas of any given person’s life; driving not only education and professional successes but more importantly the individuals life style and further goal oriented aspirations. Yet, while intelligence within itself is one the most important or influential components reinforcing an individual’s outlook on life and behavior, the ways in which intelligence is measured and develops throughout a person’s life is a little bit more misunderstood and challenging to pinpoint. Intelligence, and furthermore a person’s IQ as defined by various testable measures, has been subject to controversy for decades; raising significant questions about the neurology of the brain to

For example, displayed by an experiment with rat subjects by Rosenzweig and Bennett (1996), the thickness of the prefrontal cortex of the adult rats were affected by the relationship between its development and early “enriching”, and stimulating environments that the rats were exposed to. Suggesting that intelligence is also at the mercy of environmental factors: healthy, detrimental or otherwise; and is imperative for childhood development. While the prenatal or “maternal” environments affect more of the heritability of the individual rather than the classical external environment; the “in-utero” environment has shown another possible explanation for intelligence development. Devlin, Daniels and Roeder (1997) illustrate that, “There is substantial brain growth in utero, and the brain has 70% of its final mass within the first year of birth”. Additionally, birth weight has been indicated to be positively correlated to intelligence or IQ (Churchill 1965; Lynn and Hattori 1990). In fact, individuals born as twins generally weigh less than their non-twin counterparts; “averaging 4-7 points lower on IQ tests” (Husen 1963). Twins, on average, have a striking correlation between their IQ’s thought to be due to their shared maternal environment (Devlin, Daniels and Roeder 1997). Further suggesting that genetics and heritability are important determining factors in the development of intelligence in children, especially twin born