SSRN-Where Does it Go? Spending by the Financially Constrained by Shawn Allen Cole, John Thompson, Peter Tufano:
"Those selecting earlier settlement options pay higher fees and interest, therefore revealing the level of credit constraints or impatience. We find that more credit constrained or impatient individuals spend their monies more quickly. The mix of cash and merchant transactions is similar between more and less constrained groups. Finally, the primary merchant uses of refunds are to pay for necessities (grocery stores, gas stations, etc.), and the fraction of the refund spending devoted to these necessities is higher for those with greater revealed credit constraints."So if we focus on the last sentence, I guess the need for food and basic necessities trumps financial theory.