Evolution of rhythm as an indicator of mate quality

Abstract

Regular rhythmic repetition is a basic element of music in all human cultures and appears in numerous animal courtship signals. We propose that rhythm can function in courtship displays as an indicator of underlying mate quality. We constructed a model to explore whether regularly repeating patterns can serve as amplifiers of the performer's underlying neural quality. Our co-evolutionary simulation comprises male “songs” and female preferences, represented by bit strings. Males produce songs by copying their inborn template with some noise, depending on their quality. The females in turn assess male quality by comparing the male song to their own template. Our model shows that rhythmic songs enable greater discrimination with regard to quality than non-rhythmic songs under a variety of circumstances, thereby implying that rhythmic signals may evolve as useful mate quality indicators.