Three types of behavioural procedure have traditionally been used to investigate interval timing in humans and other animals: estimation, production and reproduction. In humans, the first two protocols tend to rely on verbal instructions or responses, requiring the participant to translate between performance and a verbal representation of duration, which can lead to confounds. A more reliable approach, which can be used equally well with a wide variety of animal species, is to use a reproduction procedure, in which the subject is presented with a given criterion duration and then required to reproduce this duration (FIG. 2).