To me, the old adage that you get what you pay for always felt too simplistic when applied to something as ephemeral as wine.

The notion of a linear correlation between price and quality becomes increasingly flaky the more you spend. By the time you reach "seriously pricey", external factors from marketing hype to the ego of the winemaker often drown out what's in the bottle.

Yet there have been plenty of studies where people given the same wine in different bottles with supposedly different prices have repeatedly claimed that the more expensive ones are more enjoyable. Proof of man's innate gullibility you might say, but not according to a recent report from the University of Bonn.

Volunteers were wired up to a brain scan and offered five bottles which they were told cost from £3 to £55. In fact only three wines were involved, two of them priced the same. The higher the cost the more the brain's pleasure receptors lit up with glee. It is as though we swallow a wine and its price tag at the same time and judge it accordingly. In other words if we think it's cheap it will taste cheap, and the converse is true.

According to the economist Mike Veseth, the wine buyer's biggest mistake is to confuse price and quality. In his forthcoming book Money, Taste and Wine he explains how retailers exploit this tendency by, among other things, pumping up the price only to discount it. Maybe some naïve part of the brain thinks it's enjoying a £10 bottle even though we paid its true value of a fiver.

Scientists call this the placebo effect where preconceptions influence our experience. The US journal that reported the Bonn study saw all kinds of exciting implications for the wine trade, and wrote: "Marketing actions can change the very biological processes underlying a purchasing decision, making the effect very powerful indeed."

If they want to mess with our minds, the best defence is to acquire some knowledge. To quote the drinks writer, Jonah Lehrer: "If the only story we can tell about wine is its price, then our pleasure will always be linked to cost, even though this link doesn't exist in most taste tests." Knowledge is not only better, it's free. On which note Great Grog are holding their spring wine fair in Edinburgh next Friday.

www.greatgrog.co.uk/events