Consistent with our model, advertised preferences for gender, age, height and beauty all become less prevalent as job skill requirements rise.

Early last week, Ms. Stone said, she received a call from Sidney Toledano, the chief executive of Dior, which hired the actress for beauty advertisements in 2005.

Vivendi, a telecoms and media group, for instance, found Aliza Jabès, the glamorous founder of NUXE, a beauty-products firm, having used her in an ad campaign for its corporate mobile-phone products.