This is an interesting article in Fortune magazine. It connects fMRI study of reward with 'Why It's So Hard to Save for Retirement'. An excerpt: "When researchers set up a table of 30 different jams in front of a gourmet market in California, 3% of the shoppers who stopped at the table bought a jar. When they displayed only six jams, 30% bought. In jam selection, as with 401(ks)s, too much choice can cause brainlock."
If you want to check out one of Cohen's papers, we've linked one below that looks at factors influencing reward-based decision-making.
Why It's So Hard to Save For Retirement - FORTUNE
Brain Reward Mechanisms Makes Decisions Within Context