The discussion of whether people understand themselves and others by using theories of behaviour (theory theory) or by simulating mental states (simulation theory) lacks conclusive empirical evidence. Nichols et al. (1996) have proposed the Langer effect (Langer, 1975) as a critical test. From people’s inability accurately to predict the difference in the subjective value of lottery tickets in choice and no-choice conditions, they argued that people do not simulate behaviour in such situations. In a series of four experiments, we consistently failed to replicate the original difference between choice and no-choice under the conditions used by Nichols et al. We conclude that the replicability of the effect depends on an unknown combination of factors. As long as the target effect is not better understood and under better experimental control, it is difficult to use it as a yardstick against which the accuracy of simulation can be assessed.