Mark D. White
Last month, The Economist published an article (based on research published in Journal of Marketing) on consumers' irrationality when compared discounts and added content:
Consumers often struggle to realise, for example, that a 50% increase in quantity is the same as a 33% discount in price. They overwhelmingly assume the former is better value. In an experiment, the researchers sold 73% more hand lotion when it was offered in a bonus pack than when it carried an equivalent discount (even after all other effects, such as a desire to stockpile, were controlled for).
In a recent issue, the magazine printed a letter by Rory Sutherland of Ogilvy & Mather UK, succinctly and humorously pointing out the problem with attributing irrationality to such consumers:
You mentioned research which revealed that shoppers often prefer “50% extra free” to a notionally more generous 30% reduction in price, and you cited this as evidence of irrationality or poor mathematical ability on the part of consumers. I think you may be wrong and consumers may be right.
There is, as the advertising sage Jeremy Bullmore observed, a significant difference between a bonus and a bribe. A price tells you much more about a product than merely what it costs. A price cut may be sensibly perceived as a mark of mild desperation on the part of the seller and it is not unreasonable to infer from a price cut that a product is an inferior good. Charging the full price but adding something extra does not convey the same desperation. In any case this whole debate is silly.
If people value 50% extra free more highly than 33% off, then that is an end of the matter. Since all value is subjective, what you are doing by offering the former is simply creating more perceived value at a lower cost. Whether or not the resulting behaviour conforms to some autistic neoclassical idea of rationality is irrelevant.
If the sole purpose of life was to be rational, we would have banned golf years ago.
Mr. Sutherland said it better than I ever could--and I've tried, in many places and many contexts, including previous posts (such as here), book chapters, and my forthcoming book, The Manipulation of Choice: Ethics and Libertarian Paternalism. Economists--of both mainstream and behavioral varieties--all too often see irrationalities where none exist because they insist on interpreting choice through the lens of their narrow understand of decision-makers and the overly simplistic choices they assume on consumers' parts.
The factors that consumers take into consideration when make choices are much more complicated than economists recognize--as Mr. Sutherland points out. And while behavioral economists are making headway in identifying some of these factors, they still don't account for qualitative ones like principles and ideals. Nor do they consider the complex and subjective interests of consumers (and all decision-makers), choosing instead to assume simple unitary goals like wealth-maximization. Until they take these common influences on choice into account, they will see irrationalities wherever they look--which reflects more on the shortcoming of their models than on the decision-makers themselves.