Tonight is the first night of Hanukkah, which is, as Adam Sandler has correctly noted, a rather unsatisfying holiday. It’s typically sold to impressionable Jewish kids as being better than Christmas, since there are eight days of presents, and not just one climactic morning. But as one soon discovers, those eight days are a bit deceiving. The way Hanukkah typically works – at least in my family – is that all the good presents arrive on the first night (the new bike, the big Lego set, etc.) followed by seven days of diminishing returns. In my childhood, the last night of Hanukkah was usually reserved for mechanical pencils and other “gifts” that were actually school supplies.
I know what you’re thinking: what an ungrateful brat! Besides, isn’t a new mechanical pencil better than nothing? If humans were rational creatures, the answer would be yes. Alas, Hanukkah doesn’t take place in an economics textbook, and that mechanical pencil actually devalues the shiny bike of seven days earlier. This is known as the peak-end rule, and it has important implications for the distribution of gifts over Hanukkah.
Let me explain. In the mid-1990’s, the psychologists Donald Redelmeier and Daniel Kahneman came up with a brilliant research project. They studied two groups of patients undergoing colonscopies. One group received a standard colonoscopy. The second group received the same treatment, except that at the very end of the procedure the doctors let the instrument sit in place for a few extra minutes. (This is relatively painless, at least when compared to the probing that comes before.)
Which group experienced less pain? At first glance, the answer seems obvious: the first group should report less overall pain, since their procedure was a few minutes shorter. But this isn’t what happened. The second group experienced significantly less discomfort. Of course, this is a completely counterintuitive reaction, since it implies that the way to make a medical procedure less painful is to make it last longer. According to Kahneman, the only trick is to make the additional minutes represent a relative decrease in the intensity of pain. When doctors listened to Kahneman’s advice, patients were more likely to return for a follow-up colonoscopy.
How did the psychologists explain this counter-intuitive result? According to Kahneman, people judge their sensory experience relative to a reference point, which in this case was the painful sensation of a camera probing their intestine. As a result, when the probe stopped moving, what the subjects perceived was a relative decrease in pain, which felt nice. The happy ending made up for the overall increase in painful moments. (This is known as the peak-end rule.) As Kahneman observes, “A general property of perceptual systems is that they are designed to enhance the accessibility of changes and differences. All perception is reference-dependent.”
The lesson is clear: if you want to improve Hanukkah, simply improve the final night, and save some big gift for that last lighting of the menorah. The happy ending will conveniently erase all those memories of mechanical pencils.