Theorists have proposed, and researchers have reported, that intelligence is a set of relatively stable abilities, which change only slowly over time. Although intelligence can be seen as a potential, it does not appear to be an inherent fixed or unalterable characteristic. … Contemporary psychologists and other scientists hold that intelligence results from a complex interaction of environmental and genetic influences. Despite more than one hundred years of research, this interaction remains poorly understood and detailed. Finally, intelligence is neither purely biological nor purely social in its origins. Some authors have suggested that intelligence is whatever intelligence tests measure.
Comprehensive Handbook of Psychological Assessment
Intellectual and Neuropsychological Assessment
edited by Gerald Goldstein and Sue R. Beers
Relations between Intelligence and Achievement Test
by Michael C. Ramsay and Cecil R. Reynolds