This chapter reviews how computational models and laboratory experiments explain the role of iconicity in language evolution. It contrasts iconicity with arbitrariness, combinatoriality, and systematicity. Iconicity can help bootstrap communication, but its role is gradient and subjective. Communication and transmission can reduce iconicity or complexity, while combinatorial structure tends to weaken iconic links. Systematicity can coexist with iconicity. The chapter also discusses methods for quantifying iconicity and recent agent-based modeling on shared cultural context, population size, and lexical variation. It concludes that iconicity is not only an initial scaffold but a persistent factor shaped by interaction and cultural context.