In February last year, we described how BMW is getting inside the heads of its potential customers, by investigating "neuromarketing". This is effectively trying to measure exactly how the decision-making cogwheels in our brains spin when we decide we want to buy a Beemer. Or, indeed, why we might decide we'd really rather drive something less pushy instead.

BMW's big rival Mercedes-Benz is not to be left out in this pursuit of the customer's innermost reflexes. Mercedes Customer Research has enlisted the help of the Fraunhofer Institute in Rostock and the Munich Technical University to measure the driver's emotional response to piloting a three-pointed star.

MB's method, seemingly based on the Voight-Kampff test dreamed up by author Philip K Dick, combined voice analysis, facial-expression recognition and psychological questioning. Test subjects were strapped into cars and, presumably, asked to recite only the good things about their mother while trying not to crash.

To ensure they were able to establish different emotional benchmarks, the German boffins took eight drivers aged between 33 and 53 - a mix of men and women - and made them drive two different cars: a brand new C-Class and an old Mercedes-Benz 190E from 1983. Of course if it had been really sincere in plumbing the depths of negative emotions it should really have given them a Mk 1 A-Class - complete with rock-hide ride, low-rent interior, squat driving position and artic-obscuring screen-pillars. And then it could have shooed some livestock onto the test track.

"The drivers had a joyful smile on their faces more often and for longer when driving the new C-Class as opposed to the Mercedes-Benz 190E," the company reports, in a shock result for science. The firm was brave enough, however, to divulge that enjoyment varied: "The more experienced motorists also enjoyed driving the older car. For example, they smiled when the rear end drifted slightly on the tight bends of the handling course." Part of that joy, of course, might have been explained by the fact that someone else would be paying for any repair bills should everything get a little too sideways.

"The pilot study showed that driving pleasure can be measured," the company concludes. No excuse, then, for another A-Class-style clunker.