If you have a great psychology book that you recommend, please let me know.  As frequent readers of this blog know, I am fascinated with psychology experiments.

In a recent blog from fivethirtyeight.com, the author tackles the question of whether people eat more when they know they are splitting a dinner check. Does it Make Sense to Split The Check at a Restaurant?

Here’s an excerpt:

In 2004, a study in The Economic Journal, a publication of the Royal Economic Society, …the researchers told four groups of diners (always three men and three women) to split the bill equally among them. They told another four groups to pay for what they had ordered. Lastly, they told two lucky groups that they would get their meals for free…

Those who were getting a free meal spent the most … Those who were splitting the bill spent less, and those who were paying individually spent the least…

Any time you make a decision that affects someone else without considering how it might affect that person, whether positively or negatively, you create an externality — it’s basically a fancy way of saying “indirect effect.” There are positive externalities (e.g. when you decide to get a flu shot, other people benefit) and negative externalities (e.g. when you decide to fart, other people suffer).

The unscrupulous diner’s dilemma reveals how negative externalities — and even the mere threat of negative externalities — affect our behavior. Participants in the bill-splitting experiment expected the others to order more, so they tried to maximize what they could get out of the situation by ordering more themselves.

Bottomline: It is fascinating to me how something as simple as splitting a bill may encourage someone to order a lot more.

Related blog posts:

• Don’t miss the gorilla! | gutsandgrowth
• Psychology of obesity and food addiction | gutsandgrowth
• Lunchroom Makeover | gutsandgrowth
• Bystander effect –Genovese syndrome | gutsandgrowth