In answering this question, I will assume that “low-class background” refers to a low socioeconomic background.
The good news for anyone from a low socioeconomic background is that your intellectual potential is determined to a large extent by the genes you inherit. In 2011, a large group of researchers published a paper stating: (See: Davies, G., A. et al., 2011. “Genome-wide association studies establish that human intelligence is highly heritable and polygenic.” Molecular Psychiatry. 16. pp. 996–1005.) They reported:
Our results unequivocally confirm that a substantial proportion of individual differences in human intelligence is due to genetic variation, and are consistent with many genes of small effects underlying the additive genetic influences on intelligence. … [Furthermore] purely genetic (SNP) information can be used to predict intelligence.
This research estimated the heritability of IQ to be about 0.5, confirming the results of the studies involving twins. Its conclusion that general intelligence is polygenic, i.e., it derives from a combination of many genes supports the concept of intelligence as a multi-faceted characteristic.
The genes you inherit come from your parents, each contributing an allele that comprises that gene. However, you could inherit genes that make you more or less intelligent than your parents. For example, imagine that each of your parents has n alleles that combine at your conception to form your intellectual potential. Think of these alleles as a hand of n playing cards, of which about one-third are face cards if your parents are of average intelligence. During your conception n/2 cards are drawn from each parent. If the cards you draw from both parents are mainly face cards, you will have more intellectual potential than either parent and your potential IQ would be much greater than theirs. If you inherited their “pip” cards, your intelligence would be less than theirs.
So, the inherited component of your intelligence depends to some extent on the number of face cards (or strong-intelligence genes) possessed by your parents. Children from highly intelligent parents are drawing their genes from decks rich in face cards, but regression to the mean (i.e., the rules of probability) suggest that they will be more intelligent than average but not as intelligent as their parents. Similarly, children from low intelligence parents will likely have lower than average intelligence, but will be more intelligent than their parents.
So why do so many highly intelligent people come from parents of medium or high socioeconomic status (SES)? People of high intelligence are more likely (though not always) to be educated, have higher incomes and therefore have higher SES. Therefore those of higher SES status are more likely to have children who are more intelligent than average. For the same reason, those of low SES status are more likely to have children of lower than average SES. Added to this is the fact that children growing up in an environment that values learning and education are more likely to experience the cognitive stimulation in their early youth that is needed to enhance neural growth.
Of course, all of these factors follow the rules of probability, so there are many highly intelligent people who come from low SES environments and many intellectually mediocre people from the high SES families. Many children in gifted programs come from homes that have very modest income. Earlier this week I included in my post the story of Chris Langan, advertised as “the smartest man in America,” who has a very high IQ but came from an economically-challenged single-parent family. Brilliant minds emerge from all kinds of SES environments, but the probabilities dictate that there is a correlation between intelligence and SES status.
Amid all the discussions about intelligence and IQ, I am always subliminally aware of a pervading comment from my Grade 10 math teacher many moons ago, “You have as many brains as you use.”
