Stable Randomisation

We design a laboratory experiment to identify whether a preference for randomisation defines a stable type across different choice environments. In games and individual decisions, subjects face 20 simultaneous repetitions of the same choice. Subjects can randomise by making different choices across the repetitions. We find that randomisation does define a type that is predictable across domains. A sizeable fraction of individuals randomise in all domains, even in questions that offer a stochastically dominant option. For some mixers, dominated randomisation is responsive to intervention. We explore theoretical foundations for mixing, and find that most preference-based models are unable to accommodate our results.