The goal of this research is to study learning and
forgetting in operations where each repetition is followed by a break. The
objective is to predict the learning parameters of relatively long tasks with
no breaks and then, to predict the behavior of the learning slope of these
tasks with respect to various break lengths between consecutive repetitions.
A few experiments were conducted in order to test the
research hypotheses. The experiments were meant to simulate the case of breaks
between consecutive repetitions. Forgetting was measured for two types of
tasks: a combined cognitive and motor task and a cognitive task.
The results revealed that the learning slope of a
combined cognitive and motor task changes when moving from the transient state
to the steady state.
A questionnaire was developed in order to predict the
learning slope of tasks and revealed a good predictive ability.
In order to predict the time to execute the first
repetition of the task, a method that uses a graph of the dimensionless ratio
between the execution time of the first unit and the standard time of the task,
as a function of the learning slope, was used and resulted in a good accuracy.
A mathematical procedure is proposed for summing
several learning curves into a single learning curve. This procedure resulted
in a very good prediction.
It was found that forgetting takes place for the
combined cognitive and motor task, but there is no forgetting for the cognitive
task. A model for finding the learning slope taking forgetting into account is
suggested and tested to show very accurate predictions.