Illegitimacy, Child Abuse and Neglect, and Cognitive Development
This study explored the relationship between illegitimate birth and cognitive development among 513 boys on probation. Prior research has shown that being part of a single-parent household leads to diminished verbal capacities and often puts a child in greater danger of abuse and neglect. Frequent abuse is thought to lead to the enhancement of visual and spatial skills relative to verbal skills through a process of “frozen watchfulness”. I hypothesized that illegitimate boys from one-parent homes would have greater verbal-performance discrepancy scores than would boys from other combinations of birth status and family structure. These boys had the lowest verbal IQ and highest performance IQ scores and, hence, the largest discrepancy. These boys also suffered the highest degree of abuse and neglect of all four birth status/family structure combinations studied.
Walsh, Anthony. (1990). "Illegitimacy, Child Abuse and Neglect, and Cognitive Development". The Journal of Genetic Psychology, 151(3), 279-285. http://dx.doi.org/10.1080/00221325.1990.9914617