Le rôle des influences interpersonnelles dans la détermination des cours boursiers

[fre] The role of interindividu al influences in the determination of stock prices. . Modem economic theory has shown that there is no incompatibility between the assumption of rational behavior and the possibility of speculative bubbles. Nevertheless the theory of rational bubbles is incomplete insofar as it tells us nothing about the kind of rational exploitation of information that gives lise to a bubble. Our idea is that, at the roots of bubbles, we find a rational use of the information contained in the average opinion of the market. Under certain conditions, this use, which follows the bayesian rules, will conduct to a self-validating mimetic contagion. This process converges to, what we have called, a rational mimetic bubble. [eng] The role of interindividu al influences in the determination of stock prices. . Modem economic theory has shown that there is no incompatibility between the assumption of rational behavior and the possibility of speculative bubbles. Nevertheless the theory of rational bubbles is incomplete insofar as it tells us nothing about the kind of rational exploitation of information that gives lise to a bubble. Our idea is that, at the roots of bubbles, we find a rational use of the information contained in the average opinion of the market. Under certain conditions, this use, which follows the bayesian rules, will conduct to a self-validating mimetic contagion. This process converges to, what we have called, a rational mimetic bubble.