Аннотация:This paper investigates how such a trivial device as a shopping cart may surprisingly contribute to shaping exchanges in supermarkets. First, the shopping cart completely modifies consumers' calculations. It does so by leading them to accomplish particular gestures, by transforming a budgetary constraint into a volumetric one, and by providing them with true calculative tools. Second, shopping with a cart also implies some `planned' cognitive processes. These processes concern interplay between family needs, selection equipment (such as a shopping list) and market information (packaging, for example). The combination of these elements moves the consumer from mere calculation (price-based computing) to `qualculation' (i.e. quality-based rational judgements). Third, and in particular, since it favours the transformation of the individual consumer into a collective one (or `cluster', i.e. a small group of people gathering around the same device), a shopping cart functions as a scene or as a frame for collective `calqulation' (from the French verb `calquer', i.e. adjusting one's standpoint to that of another, and vice versa).
