Final answer:
Intelligence-testing scores can drop due to socioeconomic factors such as poverty, which affects brain development and function. Cultural biases in intelligence tests also contribute to discrepancies in scoring among different demographic groups. Nutrition and environmental stimulation during early childhood crucially influence intelligence levels.
Step-by-step explanation:
Intelligence-testing scores tend to drop in children who come from low-income households. This can be attributed to several factors, including limited resources, higher stress levels related to daily survival, and less exposure to enriching experiences that foster cognitive development. Children in poverty often experience pervasive stress, which can negatively impact brain function and development, leading to lower performance on standardized tests and IQ measures. Furthermore, children from disadvantaged backgrounds might also be exposed to bias in testing methods, as seen in cases such as Larry P. v. Riles, which highlighted cultural unfairness in tests normed on White children. This resulted in the misclassification of African American children. It is also important to note that food insecurity can play a role, as evidenced by children performing worse in school when they have less access to food towards the end of the month.
Additionally, early childhood conditions play a significant role in intelligence development. A child's environment, including the level of stimulation and opportunities for learning, drastically shapes their intellectual growth. Historical longitudinal studies, such as Lewis Terman's study of children with high IQs, have shown that social and environmental factors, not just genetics, contribute to the development of intelligence.