The GAP is the cognitive intelligence gap (inherited) , and ambition gap (environmental)
The Bell Curve: Intelligence and Class Structure in American Life is a 1994 book by psychologist Richard J. Herrnstein and political scientist Charles Murray, in which the authors argue that human intelligence is substantially influenced by both inherited and environmental factors and that it is a better predictor of many personal outcomes, including financial income, job performance, birth out of wedlock, and involvement in crime than are an individual’s parental socioeconomic status. They also argue that those with high intelligence, the “cognitive elite”, are becoming separated from those of average and below-average intelligence.
The book was and remains highly controversial, especially where the authors discussed purported connections between race and intelligence and suggested policy implications based on these purported connections. Shortly after its publication, many people rallied both in criticism and in defense of the book. A number of critical texts were written in response to it.