  In this paper, we examine the solvability of a functional equation in a
Lipschitz space. As an application, we use our result to determine the
existence and uniqueness of solutions to an equation describing a specific type
of choice behavior model for the learning process of the paradise fish.
Finally, we present some concrete examples where, using numerical techniques,
we obtain approximations to the solution of the functional equation. As the
straightforward Picard's iteration can be very expensive, we show that an
analytical suboptimal least-squares approximation can be chosen in practice,
resulting in very good accuracy.
