Contribution of the stochastic force to the first moment of a system due to the interaction with another system

There are stochastic systems in which the stochastic force is not involved in the first moment description. However, interaction with another system may make the stochastic force contribute to the description of the first moment. The contribution to the first moment may still be appreciable even for a small interaction parameter value. Two coupled modified Verhulst population growth models are employed to show that the first moment may still be appreciable even for small interaction parameter values.