In his book Tightwads and Spendthrifts , marketing professor Scott Rick promises advice for “financial aspects of intimate relationships.”  What got my attention early is that his guidance “is rooted in rigorous behavioral science.”  Applying the scientific method to human interactions is challenging, but it is generally better than relying on opinions.  The book gives useful insights into how people think about spending money. The introduction gives a four-question quiz designed to place the reader on a scale from 4 to 26.  Those at the low end of the scale are called tightwads, and those at the other end are spendthrifts.  Roughly half the respondents fell in the middle third of the range and are called “unconflicted consumers.”  Most of the book deals with tightwads, spendthrifts, and their interactions; little is said about unconflicted consumers. Demographic differences Extensive surveys revealed some interesting demographic differences between tightwa...