The diffusion dynamics of choice: From durable goods markets to fashion first names

Goods, styles, ideologies are adopted by society through various mechanisms. In particular, adoption driven by innovation is extensively studied by marketing economics. Mathematical models are currently used to forecast the sales of innovative goods. Inspired by the theory of diffusion processes developed for marketing economics, we propose, for the first time, a predictive framework for the mechanism of fashion, which we apply to first names. Analyses of French, Dutch and US national databases validate our modelling approach for thousands of first names, covering, on average, more than 50% of the yearly incidence in each database. In these cases, it is thus possible to forecast how popular the first names will become and when they will run out of fashion. Furthermore, we uncover a clear distinction between popularity and fashion: less popular names, typically not included in studies of fashion, may be driven by fashion, as well. INTRODUCTION Understanding how individuals make choices and how these choices interplay is a fundamental problem, common to many sciences. For more than 40 years, marketing economics has been successfully using mathematical models based on the theory of diffusion processes to predict how individual-level choices to purchase innovative goods spread across society [1-3]. Similarly, we propose a mathematical framework to describe individual-level choices to adopt fashion and apply it to the case of first name data. Choosing a baby’s name appears to be a difficult task: advice from friends and family, countless books, websites, and even name consultants are feeding parent’s anxiety to select the right name. These parental concerns are historically recent, as first names were transmitted, rather than chosen, until the beginning of the 19th century [4, 5]. Nowadays, parents explicitly rely on taste-based arguments to explain their choices [5]. Hence, over time, various first names grow into fashion, then peak and go extinct.