This is the first in a series of posts using research directly from our new book Psychology Sorted. The study we’re looking at today is Luby et al. (2013) on how children’s brain development and therefore their cognitive development are affected by poverty. The researchers found that exposure to poverty in early childhood impacts cognitive development by school age. However, the effect is mediated positively by good caregiving and negatively by stressful life events.
This is highly relevant in light of reports from the UK, USA and South-East Asia of the large, and in some cases growing, number of children living in poverty. This research can be used as an example of both localization and neuroplasticity within the Biological Approach, and to illustrate the influence of poverty/socio-economic status on cognitive development, for those studying the Developmental Psychology option.
This was a longitudinal study of 145 children from a sample of children already enrolled in a 10-year study of preschool depression who, prior to being scanned by MRI, had undergone regular testing. Once a year (for a duration of 3-6 years) the children had taken part in a series of tests aimed at measuring their cognitive, emotional and social aptitudes. The involvement of significant adults in their lives was also recorded (e.g. how close they were to their caregivers) as well as the occurrence of any negative and stressful events in their lives. Once this collection of information had been amassed, each child underwent two MRI scans – one of the whole brain and one of the hippocampus and amygdala only. This study can therefore also act as an example of the use of brain-imaging technology as a technique used to study the brain in relation to behaviour.
Both the hippocampus and the amygdala showed less white and grey matter in the MRI scans of the poorer children in this study, with a positive correlation between income/needs being met and brain volume. While both the hippocampus and amygdala showed less development in poverty-affected children the researchers found that in cases where the child experienced positive care there was less negative effect on the hippocampus. Difficult and stressful life events only affected the left hippocampus.
Of course, students and teachers need to evaluate the use of this research as well: how valid is the study as an illustration of both localization and neuroplasticity? This was a relatively small sample of pre-schoolchildren from the USA who exhibited symptoms of depression. Moreover, attempting to measure complex variables (e.g. the nature of caregiving and behavioural responses) is beset with difficulties as these variables are not exact and may lack construct validity. Nonetheless, there was triangulation of methods, with the background data from cognitive testing providing a rich backdrop for the results of the scans, and this research is supported by other studies, such as that by Duval et al. (2017).
Encourage your student to find and read media and academic examples of evidence and counter-evidence, and to engage in critical thinking and evaluation. For example, some poor families often cannot afford pre-school kindergartens for their children, who may be raised to some extent in isolation as well as in poverty. This could be a confounding variable. Are there others? The student who is thinking like this is well on the way to writing a good argumentative essay on the effects of poverty on childhood cognitive development.