ECONOMIST PATIENCE, PATIENCE
By Tim Harford
Wednesday, December 06, 2006
One of my young daughter's favourite bedtime stories is A Birthday for Frances by Russell Hoban. I like it too, for the charming illustrations, hilarious dialogue and instruction in cutting-edge behavioural economics.
Frances, the story's young heroine, secures an advance on her pocket money in order to buy bubblegum and a Chompo bar as a birthday present for her little sister, Gloria. Yet as she returns with her father from the sweet shop, Chompo bar in hand, Frances begins to think of all kinds of reasons why she, not Gloria, should eat the chocolate.
"You would not eat Gloria's Chompo bar, would you?" asks her father, anxiously. "It is not Gloria's yet," replies Frances, but the reply is muffled because she is already chewing on Gloria's bubblegum.
Traditional economists would read Frances's behaviour as purely Machiavellian: she lied to her parents to get her hands on chocolate that she never dreamed of giving to her sister. Most normal people would take a kinder view of Frances's failings: she intended to give the candy to Gloria but when it was actually in her hands, the temptation to eat it herself became overwhelming.
Mainstream economics has no way to describe Frances's behaviour because it describes people as being impatient in a consistent way: if I would rather have £110 on January 6 than £100 on January 5, then logically I would always be happy to wait a day for a gain of 10 per cent, and I would rather have £110 tomorrow than £100 now.
Most people do not actually behave like this... The "now" has a strong pull, and almost everybody says they are happy to wait a day at some future time, but not today. They would prefer £100 today than £110 tomorrow, and while they say they would prefer £110 on January 6, come January 5 if you ask them again they will change their minds, just as Frances did.
It is possible to formulate such preferences in economic models - in fact, this year's Nobel laureate, Edmund Phelps, did so in a paper with Robert Pollak in 1968 - but they have only recently flowered into a full set of explorations and calibrations by economists such as David Laibson of Harvard, and Matthew Rabin.
One of the results is that we have a sense of just how strong the pull of the "now" actually is. The answer is that anything on offer right now is worth half as much again as it would otherwise be; that also means that any immediate cost, such as the pain of going to the gym, is similarly inflated. Of course the costs will vary across people and across temptations, but that seems to be a consistent finding.
These insights can be used to help people make better decisions. For example, the economist Richard Thaler has proposed a plan called "Save More Tomorrow", in which employees make commitments to contribute to their pensions not now, but later. Early trials show dramatic success in increasing contributions.
In that particular case it seems obvious that Professor Thaler helps people make the decisions they really want to make. But not all such pre-commitment devices are as successful: just think of the people who subscribe to gyms and never exercise, or highbrow journals they never read.
So we are still far from understanding how much sophisticated people will or should plan to deal with their own likely failings. Frances was perhaps too young to realise that when the Chompo bar was in her hand, she would submit to temptation. Sometimes the rest of us do better; sometimes not.
