Vaughan Bell remembers Black Magic chocolates, familiar to British shoppers and "produced by Rowntree’s who were a pioneer in using empirical psychology to design products." He excerpts a fascinating article on the marketing scheme:
The National Institute of Industrial Psychology interviewed 7,000 people over six months on their conception of the perfect chocolate assortment. In another survey, 3,000 preferences for hard, soft, and nut centres exactly determined the proportions of chocolate types in the assortment. Retailers were consulted and their recommendations on margins and price maintenance were followed carefully. Shopkeepers, moreover, supplied information on buying behavior, and it was discovered that most assortments were purchased by men for women and that they were influenced entirely by value rather than fancy boxes. The now familiar, simple black-and-white box was distinctive and chosen from fifty similar designs.
The marketing was then focussed not on the qualities of the product, but on its potential use in developing relationships.