Final answer:
Differences in average intelligence between groups are primarily driven by environmental factors, although a genetic component exists. The concept of Range of Reaction and numerous studies support the importance of environmental influences, especially during childhood, for cognitive development and intelligence expression.
Step-by-step explanation:
Research suggests that differences in average intelligence between groups, such as ethnicity, are primarily driven by environmental factors. While there is a genetic component to intelligence, evidenced by studies such as Bartels et al. (2002) which note the influence of genetics in setting the level of intelligence, it is the environmental factors that provide stability and opportunities for cognitive abilities to manifest. Cultures and socio-economic environments play crucial roles, impacting the development and display of intelligence. For example, Kishiyama et al. (2009) found that children living in poverty showed reduced prefrontal brain functioning, indicating that stress and lack of resources can negatively impact cognitive development.
The concept of Range of Reaction further supports the significance of environmental stimulation, especially in childhood, in reaching one's full intellectual potential. This is in line with the findings of Csikszentmihalyi & Csikszentmihalyi (1993), where a supportive family environment contributed to happiness and likely better outcomes in individuals who are genetically gifted. The inherent complexity of these issues means that intelligence cannot be meaningfully, or ethically, associated with race—a view supported by current research, which acknowledges the closing of IQ gaps as access to education becomes more equitable (Dickens 2006).