The consummatory force of an activity is related to the nature of the activity. Instigating force from one activity can also lead to an increase in a related activity. The instigating force to eat might also increase the tendency to drink. This shared instigating force is called displacement and is handled in the simulation through arrays of values from 0-1.0. The total instigating force for an activity is the instigation for that activity plus the partial instigation from all related activities.
Substitution is a bit more complicated than displacement, however.
Only the on-going activity has consummatory force applied to it. Thus, only those activities that are related to the ongoing behavior will have substitute consummatory force applied to decrease the action tendency. Consummatory lags . The consummatory force that is applied to the on-going and dominant behavior is not applied at the instant the behavior is expressed. Instead, a lag period, which is usually from 2-5 time units, causes a delay in decreasing the action tendency due to consummatory force.