Daniel Lende captions the above chart, "The percentage of children with serious mental or behavioral difficulties is shown as a percentage on the left. The drop-off as income rises is dramatic." He excerpts the summary of the full report:
This study was designed to examine the possible association between household family income and the hippocampus, a brain region central to many important cognitive and emotional processes. … Taken together, these findings suggest that differences in the hippocampus, perhaps due to stress tied to growing up in poverty, might partially explain differences in long-tern memory, learning, control of neuroendocrine functions, and modulation of emotional behavior.
The Dish 