Time estimation in young children: an initial force rule governing time production.

Children aged 3 and 5 1/2 years were asked to carry out a response duration task in two sessions under "minimal", "temporal" and "force" instructions. In session 1, they were told to press "long enough" for the temporal instructions and "hard enough" for the force instructions. In session 2, they were asked to press "longer" or "harder" than in the previous session. Results showed that the force instructions, but not the temporal instructions, improved the 3-year-olds' timing accuracy. Furthermore, when instructed to press harder, 3-year-olds pressed longer. In contrast, 5 1/2-year-olds were more accurate with the temporal than with the force instructions; and when asked to press harder, they did not press longer. These findings suggest that 3-year-olds rely on a certain amount of force to produce correct response durations. The marked dissociation between force and duration only emerges between the ages of 3 and 5 1/2.