Science or religious war?

Are neo-classical and behavioural economics truly irreconcilable? Are the foundations of one of our great sciences crumbling before our eyes? Or, is behavioural economics a useful elaboration on the neo-classical tradition, that enriches rather than wrecks the great neo-classical insights?

My chips are on the enriching rather than wrecking side of the argument. Right here, right now, I clearly am in the minority. The sloppy-thinking chat tends to pit one tradition against the other.

Here is Elizabeth Kolbert, writing in the New Yorker.

"Rational calculators are supposed to consider their options, then pick the one that maximizes the benefit to them. Yet actual economic life, as opposed to the theoretical version, is full of miscalculations, from the gallon jar of mayonnaise purchased at spectacular savings to the billions of dollars Americans will spend this year to service their credit-card debt. The real mystery, it could be argued, isn’t why we make so many poor economic choices but why we persist in accepting economic theory."

Notice the condescension. "The real mystery...why we persist in accepting economic theory." She illustrates this self evident truth - that the assumption of rational economic behaviour is so broken that it is pitiful - with a personal anecdote.

Ms Kolbert was buying a book on Amazon for her work when a message popped up on her screen "add $7.00 to your order to qualify for FREE Shipping". She hesitated. Her nine-year-old twins wanted a Tintin book. She clicked it into the shopping cart and checked out, saving The New Yorker $3.99 and spending $12.91 of her own money.

Then comes the sucker-punch. "From the perspective of neoclassical economics, self-punishing decisions (such as this purchase of a Tintin comic) are difficult to explain." Really?

Neo-classical economics is very comfortable thinking about the Tintin comic as a bundle of information (about prices), services (delivery) and physical product (the comic book itself). Remember complements and substitutes from Econ 101? Amazon reduced the price of that bundle by flashing a free shipping advert on Ms Kolbert's screen, which reduced her tacit search costs, and by waiving the delivery charges. This prompted a purchase which otherwise wouldn't have happened. Lower price, more sales. This is the demand curve from Econ 101. There is no more unsurprising result in neo-classical economics.

Notice that the neo-classical theory makes no claims about the mechanism by which people maximize utility. In the neo-classical view people maximize utility the way a dog catches a frisbee. The calculations a dog needs to make to catch a frisbee are way beyond the scope of what a dog, or human, can consciously perform. Yet, dogs and humans successfully catch millions of frisbees every day.

This is where behavioural economics comes in. It sheds more light on the heuristics that people actually use while maximizing utility. This might prompt governments or businesses to use those heuristic mechanisms. For example, tax collections in America increased when taxes were collected at source. Once the money is in my bank account I am much more reluctant to give it to the government. Brilliant behavioural insight. By Milton Friedman, the godfather of neo-classical economics.

None of this challenges the one thought central to all of neo-classical economics: people respond to incentives. The way in which different people respond to different incentives is infinitely varied, which is why economic life is fascinating to observe.