What determines how much a man spends on an engagement ring?

The more money a guy makes and the younger the bride, the more he spends on an engagement ring.

And, no, most guys don’t spend 3 months of salary on it.

Via The Consuming Instinct: What Juicy Burgers, Ferraris, Pornography, and Gift Giving Reveal About Human Nature:

Lee Cronk and Bria Dunham investigated the amount that men spend on engagement rings as well as factors that might affect the amount spent. The average yearly income of the surveyed men was $41,858.20, with the amount spent on engagement rings $3,531.72. In other words, men spent 8.44 percent of their annual incomes on the rings, which is a far cry from the 25 percent norm. The total spent on rings was positively correlated to the annual incomes of both men and women but negatively correlated to women’s ages. 

You also might be curious what size diamond provides the most happiness.