Friday, 20 November 2015

How Your Appetite For Economics Is First Whetted: Why Does Popcorn In Cinemas Cost So Much?

Yesterday I went to the cinema to see the latest pretty average (although beautifully shot) James Bond film Spectre. I didn't have popcorn - in fact, I *never* have popcorn, because the event of watching a film doesn't induce in me the desire to eat something I wouldn't eat at any other time of the year.

However, this did conjure a reminder of what it's like to begin studying economics, because the expensive price of popcorn is one of the standard starter questions you get when you begin your studies. I recall it well, it takes me back to over two decades ago, and having my eyes awoken to how incredible the subject is and was always going to be.

The question of expensive popcorn is asked in part to whet your appetite for what is to come when you study in depth books by the likes of Deirdre McCloskey and David Friedman (Milton's son) on price theory and first learn properly about things like marginal value, marginal utility, indifference curves, price sensitivity, comparative advantage, consumer surplus and opportunity costs, but the other reason it is asked is because the answer to the question isn't anything like as obvious as it first seems.

Unbeknown to me at the time, the question "Why does popcorn in cinemas cost so much?" was a pretty standard question often rolled out for first year students, along with one about the size of shopping trolleys and whether they had got larger to meet demand or to stimulate increased buying. It was enough to get me immediately hooked.

When you're that age you have just naturally been primed to think that if cinemas charged less for a product then demand would increase. What was different about popcorn? Well, obviously once you are in the cinema with a ticket the popcorn is a pretty standard secondary purchase, and you are ostensibly a captive customer, which explains the high mark up price, right? Not quite. (Oh, by the way, cinemas make a fortune on drinks already, because the drinks they serve are about 70-80% ice).

So, the captive customer theory is a tiny proportion of the truth, but in actual fact it's not that much of a driver of popcorn prices. A price, of course, is an exchange rate between different possible goods or services, which is why competition for cinema customers occurs primarily with ticket prices not popcorn prices. In other words, if people are going to be price sensitive they are more likely to be so with the primary purchase, the ticket, not the secondary purchase, the popcorn. For that reason you are unlikely to see a cinema try to be competitive with its popcorn price.

If you lower popcorn prices you have to raise ticket prices. But raised ticket prices will disincentive people who don't want to eat popcorn, where lower ticket prices and higher popcorn prices won't disincentive ticket buyers. So higher priced popcorn enables the cinema owner to extract high sums from price insensitive popcorn eaters while not driving away price sensitive ticket buyers (in particular, families, pensioners and students - hence the pensioner and student discount tickets).

Studying price discrimination basically teaches us all the ways that sellers can attempt to charge different people different prices based on whether they are price sensitive or not (see my blog post here for more on this). But far from being an ignoble tactic worthy of scorn, it actually leads to advantages all round, as prices are more coterminous with how much value people place on the product, but also in making products more affordable to people who don't have so much disposable income.

In terms of mental exhilaration and opening your eyes to a brand new and enriching way of seeing the world, I don't think it would be overstating it if I said that I think price theory (and all its concomitant studies of behaviour, incentives, etc) is one of top 3 or 4 things a human can study. The benefits are accretive and life-changing.