Poverty and development

The economist Paul Krugman commented in the New York Times on findings from neuroscientists. Children growing up in very poor families, with low social status, experience high levels of stress hormones that may impair brain development and cognitive functioning. 17.4 percent of children in the US live below the poverty line. Based on these statistics, Krugman argued that children born to the poorest parents have an almost 50 percent risk of remaining in that position. Because of poor development, they miss social and economic opportunities.

Cognitive researchers have found that poverty is one of the major risk factors in a child’s cognitive development. Factors such as poor nutrition, poverty-related health problems, home environment, parenting practices, and living in poor neighbourhoods with high levels of crime and unemployment, are all factors that may impact cognitive development in children.

Risk factors as a result of living in poverty
Stress over meeting basic needs of food, shelter and safety
Substance abuse in the community
Exposure to environmental toxins - according to one report, one in six American children has toxic levels of lead in his or her blood; 55% of African American children living in poverty have toxic levels of lead in their blood.
Trauma caused by insecurity in their community and a lack of safety
Higher than average levels of physical and sexual abuse
Lack of educational opportunities
Less stimulation in their environment

Noble et al (2005) found that children with a lower socioeconomic status (SES) performed worse on all tests of cognitive performance compared to middle SES children. The question is why?

For years psychologists have argued that poverty has an effect on a child’s cognitive development. The problem with this argument, of course, is that there are many aspects of poverty that may be the “cause” of cognitive impairment. One of the variables that has been studied by psychologists is malnutrition.

One argument is that inadequate food intake and an unhealthy diet limits children’s ability to learn. Children who are chronically undernourished become less active and show less interest in their social environment. It is believed, however, that it is not the malnutrition alone that results in cognitive malfunctioning, but rather the combined negative effects of exposure to undernourishment and other consequences of poverty. If children are given appropriate food and stimulation, it can modify cognitive impairment caused by earlier malnutrition.

Children who do not live in poverty have a number of protective factors - that is, factors that help facilitate healthy development.  These include a balanced diet, access to good education, a stimulating environment (for example, exposed to technology and innovation), access to financial support, low stress over basic needs and access to health care.

Kar et al (2008) studied the effect of malnutrition on cognitive performance in a sample of 20 Indian children in two age groups, one from 5 to 7 years old and another between 8 and 10. The data was compared to children in a control group. Malnourished children in both groups scored lower in attention, working memory and visuospatial tasks than the control group. However, older children showed less impairment. Kar posited a theory of delayed cognitive development rather than permanent impairment - that is, a lack of a healthy diet as young children has a temporary effect on development.

ATL:  Critical thinking

Kar et al's study seems like good news.  Nutrition does not have life-long effects on development; development is simply delayed.

But what does this mean for the child who is experiencing delayed development?  Based on the findings of this study, if you were asked to do a presentation for teachers on working with children from low socioeconomic backgrounds, what would be two recommendations that you would make?

Research in psychology: Pollitt et al (1995)

Pollitt carried out a study in four extremely poor villages in central Guatemala for a period of eight years. Because it was thought that protein was the most important nutrient missing from the villagers’ diet, it was decided to give villagers a nutritional supplement. Participants were pregnant women and children under the age of 7. More than 2000 children and mothers participated between 1969 and 1977.

Participants in two of the villages received a high protein supplement called Atole. The inhabitants of the other two villages - who served as the control group - received Fresco, which contained no protein. Both supplements provided vitamins and minerals as well as calories, but Fresco only had one-third of the calories of Atole.

The findings showed a significant drop in infant mortality in both sets of villages, but with a 69% decrease in villages taking Atole and only a 24% decrease in the villages taking Fresco. Children on Fresco suffered a slower rate of growth and a slower rate of recovery from infection. They also learned to crawl and walk slightly later on average. Because these undernourished children remained small for their age, adults may have tended to treat them as if they were younger than their actual age.

A follow-up study was carried out in 1988, eleven years after the completion of the first study. The participants who received Atole in early life performed significantly better on most tests of cognition compared to those who received Fresco. Children from the lowest socio-economic level of the village scored just as high as those in the higher SES of the village. With every additional year of schooling, the differences in achievement between those children who took Atole vs. Fresco increased. However, the children from the villages still performed less well than children from a middle-income household in a more prosperous area of Guatemala.

The research above indicates that there are biological factors that influence the developmental gap between children from low and high SES levels. But could there be other factors?

One of the arguments is that children in poorer families lack environmental stimulation.  If you remember the study by Rosenzweig and Bennett, they found that a lack of stimulation in the environment led to a lack of neural development in the frontal lobe of rats.  But could this also be true in humans?

Farah et al (2008) investigated the relationship between environmental stimulation and parental nurturing on cognitive development. The sample was made up of 110 African American middle-school children.  They were evaluated at ages four and eight through a series of interviews and observations.  The researchers found that there was a positive correlation between environmental stimulation and language development. There was also a correlation between parental nurturing and long-term memory performance.

A final factor that may account for the effect of poverty on development is the role of cognitive load - that is, the total amount of mental effort being used in the working memory. If the cognitive load is too high, then it is not possible to process new information.

Research in psychology: Mani et al (2013)

Participants were from two different groups: people with an average income of roughly 20.000 and 70.000 USD. The aim of the study was to see if making the participants aware of their financial situation would impact their level of cognitive processing.

Participants were presented with four financial scenarios. For example, “Your car is having some trouble and requires $X to fix. You can pay in full, take out a loan or take a chance and not fix the car right now. How would you go about making your decision?”

Within each financial group, the participants were randomly allocated to one of two conditions. In the easy condition, the above scenario would have a value of about $150. In the “hard” condition, the above scenario would have a value of about $1500. The goal of such scenarios was to prime the participants and make their own financial situation more salient.

The participants were given a test of cognitive processing -  the Raven’s Progressive Matrices test. This is a common component of IQ tests. Participants must choose which of several alternatives best fits a space in a sequence of shapes (see the image on the right).

Findings indicated that in the “easy condition”, there was little difference in cognitive performance for either the “rich” or the "poor" participants. However, for the “poor” participants, their scores were much lower under the “hard” conditions - that is, when their financial position was made salient.

Mani argues because worry about financial realities often preoccupies the poor, they have a heavier cognitive load on a day to day basis, making it difficult to focus on more demanding cognitive tasks.

However, this is a rather artificial task, so Mani and his team went out into the “real world” to do some field work.

Field Study

The study examined 464 sugarcane farmers living in 54 villages in Tamil Nadu, India. Each of the farmers earned at least 60% of his income from the sugarcane harvest. This means that prior to the sugarcane harvest, the farmers are poor. After the harvest, they are significantly richer. This is a natural experiment, as the farmers experience cycles of poverty.

As in the lab experiment, the Raven’s Progressive Matrices test was administered both before and after the harvest. In addition, the Stroop Test was administered.

On the Raven's Progressive Matrices test, the farmers scored an average of 5.45 items correct post-harvest, but only 4.35 items correct pre-harvest. On the Stroop test, they took an average of 131 seconds to respond in the "interference condition" post-harvest, as compared to 146 seconds pre-harvest. In addition, the average number of errors the farmers made was higher before the harvest than after - 5.93 versus 5.16. The results of this experiment are significant at p < 0.001.

Once again, it is clear that poverty has an effect on the farmers’ ability to manage the cognitive load demanded by these tasks. This means that the poor are less capable not because of problems in their cognitive or biological development, but because of the context of poverty.

Evaluation of research

According to psychologists, the exact link between socio-economic background and individual development is not yet fully understood. It seems that there is a cumulative effect of positive or negative factors related to socio-economic factors. This means that individuals from more privileged homes have greater educational opportunities, more role models and higher parental expectations than children from less privileged backgrounds. However, early adverse experiences do not necessarily determine the life path of an individual. Werner and Smith (1992) carried out a longitudinal study of high-risk children and found that one-third had adjusted well to adult life. This may mean that dispositional factors rather than situational factors may play a more significant role in a child's development - as we will see in the part of this unit on resilience.

There are also several methodological considerations when discussing research on the effects of poverty.

  • Poverty is a relative term. The definition, except for the poorest of communities, is not absolute.
  • The vast majority of research is correlational in nature. This means that a cause and effect relationship cannot be established.
  • Samples are often not representational and thus the findings of studies are not highly generalizable.
  • It is impossible to isolate the many factors that may influence cognitive development which may be associated with poverty.
  • Applications of findings have improved the lives and opportunities of many individuals - for example, free breakfast programs.

Checking for understanding

Which of the following is not a risk factor for delayed development in poor neighborhoods?



Which of the following is not a limitation of psychological research on poverty?



Kar et al (2008) carried out a study of the effects of malnutrition on cognitive development in Indian children.  Their findings were that



What was the independent variable in Pollitt's 1995 study on nutrition in Guatemala?



Which research method was used in the study by Farah et al (2008) on environmental stimulation and parental nurturing in a sample of 110 African-American middle school students?



The total amount of mental effort being used in the working memory is known as



Mani's field study of sugar cane farmers in Tamil Nadu, India is an example of a(n)



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