Introduction

The most basic definition of traditions used by biologists is the one given by Fragaszy and Perry in Ch. 1. It states that traditions are enduring behavior patterns that are shared by at least two individuals and that are acquired in part through social learning. Laland, Richerson, and Boyd (1993) distinguished between two forms of social learning. The first involves primarily horizontal information transmission (i.e., between animals of the same generation) in which information is of only transient value, as in the acquisition of foraging information in a highly variable environment. In the second, information is transmitted vertically (between generations) and results in what Laland et al. (1993) call stable traditions. In this definition, socially learned information has to remain in the population for a certain period of time before it can be called a tradition. These two forms appear not to be exclusive but rather are placed at different points on a continuum. However, it is useful to consider the results of social learning in this theoretical framework to demonstrate how social learning in communication systems differs from that in other domains. We will use these concepts to review vocal traditions in mammals and birds.

By definition, every form of learning about communication has to involve another individual since communication involves at least two individuals. The only exception is learning to change the quality of a signal through practicing. However, this can be recognized by observing the performance of an isolated individual as it changes.