Repeated Occurrences of the Baldwin Effect Can Guide Evolution on Rugged Fitness Landscapes

The Baldwin effect is known as a possible scenario of interactions between evolution and learning caused by the balances between benefit and cost of learning. It is still controversial how learning can affect evolution on rugged fitness landscapes because previous studies merely focused on a process in which the population reaches a local optimum through a single occurrence of this effect, even though there exist a lot of local optimums on the landscape. Our purpose is to clarify whether and how learning can facilitate the adaptive evolution of population on rugged fitness landscapes in view of the repeated occurrences of the Baldwin effect. For this purpose, we constructed a simple fitness function that represents a multi-modal fitness landscape in which there is a trade-off between the adaptivity of individual and the strength of the epistatic interactions among its phenotypes. Phenotypic plasticity is introduced into our model, in which whether each phenotype is plastic or not is genetically defined and plastic phenotypes can be adjusted by learning. The evolutionary experiments clearly showed that the Baldwin effect repeatedly occurred through the evolutionary process of the population on this landscape, and facilitated its adaptive evolution as a whole