Some years ago I was leading a marketing project using large newspaper advertisements to solicit eager responses from readers. I consulted the experts, and I found that there was an established, comprehensive set of rules known to achieve the best results. It covered everything from choice of words to pictures to layout. It was emphasised that the product needed a sponsor of credibility whose photograph appeared prominently. While it was preferable, if expensive, to bribe the goodwill of a well-known person, it was sufficient that he or she simply appeared trustworthy. So how much weight do we put on appearances?