Slate columnist Matthew Ygelsias:
A study published last week in the journal Science shows that the stress of worrying about finances can impair cognitive functions in a meaningful way. The authors gathered evidence from both low-income Americans (at a New Jersey shopping mall) and the global poor (looking at farmers in Tamil Nadu, India) and found that just contemplating a projected financial decision impacted performance on spatial and reasoning tests.
Perhpas more importantly, as Matthew Yglesias notes, this research suggests current eligibility tests for help may be completely wrong-headed and even damaging:
This paternalistic notion that we should be relatively stingy with help, and make sure to attach it to complicated eligibility requirements and tests, may itself be contributing to the problem of poverty. At home or abroad, the strain of constantly worrying about money is a substantial barrier to the smart decision-making that people in tough circumstances need to succeed. One of the best ways to help the poor help themselves, in other words, is to simply make them less poor.
See also: Poverty Impedes Cognitive Function