Voices without words: the spectrum of nonverbal vocalisations

Nonverbal vocalisations are a fundamental part of human life. Here, we use Tinbergen's ethological framework to examine the functions, ontogenetic trajectories, evolutionary history, and underlying mechanisms of five types of vocalisations: cries, laughter, moans, screams, and sighs. Integrating insights from evolutionary biology and social psychology, we demonstrate how biological functions and social factors shape vocalisations. Tracing the development of vocalisations from infancy to adulthood emphasises the role of innate tendencies, as well as delineating processes of social learning. For each vocalisation type, we map their distinct nature and communicative potential: cries are crucial for survival and caregiving responses; laughter fosters social bonding and group cohesion; moans convey a wide range of internal states from pleasure to discomfort; screams serve as urgent alarms in critical situations; and sighs regulate emotions and signal shifts in emotional states. We conclude that both biological and social factors must be considered to understand nonverbal vocalisations.