When choices are made sequentially, agents may rely on whatever information they have obtained via observation of others’ actions. This influence resulting from rational processing of information gained by observing others is called social learning. Social learning can help explain why people tend to converge on similar behavior, in what is known as "herding". In the literature, phenomena of social learning which lead to collective imitation have also been called "information cascades" (for a survey, see Bikhchandani, Hirshleifer, and Welch (1998)). An information cascade can be defined as a choice sequence in which some agents act as if they ignored their private information and followed the choices made earlier in the sequence by other agents. Anderson and Holt (1997) designed experiments, inspired by a specific parametric model taken from Bikhchandani, Hirshleifer, and Welch (1992), to study empirically the emergence of information cascades. In their different treatments, subjects held private signals and were invited to guess publicly the content of an urn, in an exogenously given order. In this paper, we extended the experimental design of Anderson and Holt (1997) in order to allow for endogenous timing of predictions. In this respect, subjects are endowed with different quality private signals. Besides the predictions subjects report their beliefs about possible states of the world. They are encouraged to do this seriously and truthfully by the payoff generated by a scoring rule. Substantial cascades are observed and our results indicate that people learn by imitating successful others.