Central to our American mythology is the belief a person can rise to the pinnacle of success from the depths of poverty. While this does happen, poverty presents an undeniable obstacle to success. Tales within this myth of success present an inconsistent view of poverty:  the hero is praised for overcoming the incredible obstacle of poverty while it is also claimed that anyone with gumption should be able to succeed. The achievement is thus claimed to be heroic yet easy and expected.

Outside of myths, poverty is difficult to overcome. There are the obvious challenges of poverty. For example, a person born into poverty will not have the same educational opportunities as the affluent. As another example, they will have less access to technology such as computers and high-speed internet. As a third example, there are the impacts of diet and health care. These necessities are expensive, and the poor have less access to good food and good care. There is also research by scientists such as Kimberly G. Noble  that suggests a link between poverty and brain development.

While the most direct way to study the impact of poverty and the brain is by imagining the brain, this is expensive. However, research shows a correlation between family income and the size of some surface areas of the cortex. For children whose families make under $50,000 per year, there is a strong correlation between income and the surface area of the cortex. While greater income is correlated with greater cortical surface area, the apparent impact is reduced once the income exceeds $50,000 a year. This suggests, but does not prove, that poverty has a negative impact on the development of the cortex and this impact is proportional to the degree of poverty.

Because of the cost of direct research on the brain, most research focuses on cognitive tests that indirectly test the brain. Children from lower income families perform worse than their more affluent peers in their language skills, memory, self-control and focus. This performance disparity cuts across ethnicity and gender.

As would be expected, there are individuals who do not conform to this general correlation and there are children from disadvantaged families who perform well on the tests and children from advantaged families who do poorly. Knowing the economic class of a child does not automatically reveal what their individual capabilities are. However, there is a correlation in terms of populations rather than individuals. This needs to be remembered when assessing anecdotes of successful rising from poverty. As with all appeals to anecdotal evidence, they do not outweigh statistical evidence.

To use an analogy, boys tend to be stronger than girls but knowing that Sally is a girl does not mean that Sally is certainly weaker than Bob the boy. An anecdote about how Sally is stronger than Bob also does not show that girls are stronger than boys; it just shows that Sally is unusual in her strength. Likewise, if Sally lives in poverty but does exceptionally well on the cognitive tests and has a normal cortex, this does not prove that poverty does not have a negative impact on the brain. This leads to the question as to whether poverty is a causal factor in brain development.

As the saying goes, correlation is not causation. To infer that because there is a correlation between poverty and cognitive abilities then there must be a causal connection would be to fall victim to a causal fallacy. One possibility is that the correlation is a mere coincidence and there is no causal connection. Another possibility is that there is a third factor that is causing both and poverty and the cognitive abilities are both effects.

There is also the possibility that the causal connection has been reversed. That is, it is not poverty that increases the chances a person has less cortical surface (and corresponding capabilities). Rather, it is having less cortical surface area that is a causal factor in poverty.

This view does have some appeal. As noted above, children in poverty tend to do worse on tests for language skills, memory, self-control and focus. These are the capabilities that are useful for success, and people who are less capable will tend to be less successful. Unless, of course, they are simply born into “success.” To use an analogy, there is a correlation between running speed and success in track races. It is not losing races that makes a person slow. It is being slow that causes a person to lose races.

Despite the appeal of this interpretation, to rush to the conclusion that it is cognitive abilities that cause poverty would be as much a fallacy as just rushing to the conclusion that poverty must influence brain development. Both views appear plausible, and it is possible that causation is going in both directions. The challenge is to sort the causation. The obvious approach is to conduct the controlled experiment suggested by Noble: providing an experimental group of low-income families with an income supplement and providing the control group with a relatively tiny supplement. If the experiment is conducted properly and the sample size is large enough, the results would be statistically significant and provide an answer to the question of the causal connection.

Intuitively, it makes sense that an adequate family income would have a positive impact on the development of children. After all, adequate income would allow access to adequate food, care and education. It would also tend to have a positive impact on family conditions, such as emotional stress. This is not to say that just “throwing money at poverty” is a cure all; but reducing poverty is a worthwhile goal regardless of its connection to brain development. If it does turn out that poverty does have a negative impact on development, then those who claim to be concerned with the well-being of children should be motivated to combat poverty. It would also serve to undercut another American myth, that the poor are stuck in poverty simply because they are lazy. If poverty has the damaging impact on the brain it seems to have, then this would help explain why poverty is such a trap.