Is Jeremy Corbyn leader of the Labour party for the same reason that DFS is always having sales?

I ask because of a new paper by Markus Dertwinkel-Kalt of the University of Cologne and Gerhard Riener of Mannheim University. They show that, when faced with a choice between products with different types of rewards, consumers often focus (pdf) upon one eye-grabbing feature and underweight others - a decision which isn't always rational. This is closely related to the theory (pdf) that "consumers attach disproportionately high weight to salient attributes." And it's consistent with Michael Porter's advice that companies should offer customers either low prices or high quality but not be stuck in the middle.

This explains a lot of behaviour:

- DFS always has a sale because "50% off" is a more salient offer to customers than a reasonable settee at a fair price.

- The cliché for years has been that mid-market supermarkets such as Sainsbury and Tesco have lost out to those offering more salience - either Lidl's low prices or Waitrose's quality.

- Easyjet offer low air fares and then sting travellers for everything because low headline ticket prices are eye-grabbing.

Corbyn's popularity with Labour members fits this pattern. When faced with two or three candidates who were much of a mushy muchness, they plumped for the more salient option.

I suspect a similar thing might be true for the Brexit referendum. Voters' decisions will be swayed by them attaching lots of weight to a particular outstanding feature: for me, this is the short-term uncertainty that Brexit would cause.

You might wonder how all this can be consistent with the compromise effect - our tendency to choose mid-ranged options, such as middlingly-priced items on a restaurant menu.

Simple. The compromise effect works by exploiting the contrast effect, thus making the offered product more salient. The average-priced dish looks good value when contrasted to the expensive one: the modest home looks nice contrasted to the hovel. In this sense, the compromise effect and the focusing effect are compatible: both say that we choose the salient option.

This is true in politics too. An appeal to the "centre ground" succeeds if a party can credibly say: "they are extremists; we are moderates." But the claim "we are more moderate than them" often fails - as many unemployed Lib Dem ex-MPs would testify.

Herein lies a nice paradox. Corbyn, more than most politicians, is innocent of marketing tricks, behavioural economics and the darker arts of persuasion. And yet he benefited from the focusing and salience effects whilst his supposedly more PR-savvy rivals failed. Perhaps this is one more data-point in favour of John Kay's theory of obliquity - that our goals are often best achieved when pursued indirectly.