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).