There is an excellent book by a woman named Ruby Payne titled Poverty. She makes the point that it takes more than money to change a person's social status. We are raised a certain way, and those thoughts continue with us throughout life. If a child is raised in a poor environment with a poor attitude toward education, it will determine what he thinks his future holds, and how he plans to get there. I have had very smart students tell me that "I'll never go to college, so what difference does it make?" It is hard to change an ingrained message like that and "it takes a village" to do it. If a student thinks there is nothing at the end of all this work, why should he try. Also, he usually does not have the cognitive stimuli at home that other children have. His parents are usually uneducated and cannot stimulate higher order thinking. They usually work long hours and do not have time to spend with their children. If they are at home, the conversations are generally about basic survival. Also many of their home environments are not condusive to learning --- 6-7 people in a one bedroom house, sharing a room with 2-3 siblings etc. The elements of poverty work together to inhibit cognitive development.
All of these posts have provided adequate information. I would also add that unfortunately, I just saw a news segment stating the the number of American children living in poverty has risen. Not only that, many of the children have parents who are married and parents who have a college education. Many of the parents also have full time jobs. We all know that the cost of living is rising tremendously, but wages are not.
It is interesting that #4, in focusing on the various social aspects of poverty, also describes elements of a different kind of poverty, that is time poor. To be honest, I teach and have taught very many students who hardly spend any time with their parents, but not because of their poverty but because of their wealth. They are so focused on their careers that the children come a definite second. Clearly, one of the crucial elements of a child's development is the amount of time parents are able to devote to them.
I agree with the 4th post. After working in Haiti for humanitarian aid several times, I have to say that motivation for intellectual stimulation becomes less when it appears that there is not a chance to receive a formal education. For some of these people, they are plenty happy without further forced cognitive development. Now this is not always the case. Some living in the poverty-stricken conditions of Haiti choose to think and relate with others causing great stimulation and growth. When you see the same failure over and over, you believe that failure is the only option.
There are so many ways poverty can affect a child's development. It begins in the womb, with the general health of the mother likely to suffer and the lack of prenatal treatment and nutrition. This is also true early in the child's life. The child is not likely to get proper preventative medical treatment, is more likely to be malnurished, and is more at risk for serious health problems like obesity from an improper diet. There are also environmental risks, such as lead poisoning and pollution.
Poverty always restricts nutrition and often restricts restful sleep. Nutrition is essential to cognitive development and function, as is restful sleep. The diet must contain enough of the right things in the right quantities for cognition to function. Some are glucose, fatty-acids, triglycerides, minerals (including electrolytes) and vitamins. Adequate restful sleep must be available nightly. Without these--without even one of these--the brain cannot and will not function properly.
Because of the largely dysfunctional way in which schools are funded in the United States, the quality of the school systems and the schools themselves often mirror the socio-economics of the districts they are in. That is, poor districts tend to have lower quality facilities and schools. They pay less, and attract, on average, less qualified and motivated teachers (although to be fair, some are highly qualified and motivated).
So a lack of access to quality, safe and meaningful education often negatively affects cognitive development, along with lack of proper nutrition and medical care, safe environments to grow up in, and access to normal socialization.
The above posts look more at physical implications of poverty. I would choose, instead, to look at the social implications.
People living in poverty tend to be less able to present their children with a variety of "intellectual" stimuli. They are not as able to give their children lots of books and to spend a great deal of time interacting with them. They are not as able to expose them to a variety of environments by doing things like going on trips with them. Because they are unable to do things like this, they are less able to provide their children with experiences that make for better cognitive development.
Getting proper nutrition is imperative for good cognitive development! Poverty often goes hand-in-hand with poor nutrition and even vitamin deficiency. Even if starvation isn't a factor, fast foods with low nutritional value are often in play.
Malnutrition develops when the body does not get the proper amount of energy (calories), proteins, carbohydrates, fats, vitamins, minerals and other nutrients required to keep the organs and tissues healthy and functioning well. A child or adult can be malnourished by being undernourished or overnourished. http://www.factsforlifeglobal.org/05/
Further, this same malnutrition can lead to other factors that can, in turn, lead to cognitive development problems. Illness for example is a general blanket term for so many things that can happen in the body due to malnutrition, ... and any number of illnesses (apart from teh manutrition that caused them) can cause a lag in cognitive development. In this way, malnutrition can also be an indirect cause of delay.
Living in impoverished conditions can affect a child's cognitive development in many ways. Inadequate diet may stunt physical growth and can impact mental and intellectual development. Substandard housing conditions may contribute to more frequent illness and/or more severe health problems related to lack of heat or cooling, lead paint chips ingested by young children, vermin spreading disease, etc. Opportunities for exercise and outdoor activities may be limited, which can affect development of coordination that supports many areas of learning. Children in families living below the poverty line may not receive the benefits of quality interaction time with supportive adults, which can impact language development, acquisition of social skills, and readiness to learn basic concepts in academic areas.