Categorical and semantic perception of the meaning of call types in zebra finches

Vocal communication in social animals involves the production and perception of various calls that ethologists categorize into call types based on their acoustical structure and behavioral context. Whether these categories indicate distinct meanings for the animals remains unknown. The zebra finch, a gregarious songbird, uses ~11 call types that are known to communicate hunger, danger, or social conflict and to establish social contact and bonding. Using auditory discrimination tasks, we show that the birds both discriminate and categorize all the call types in their vocal repertoire. In addition, systematic errors were more frequent between call types used in similar behavioral contexts than could be expected from their acoustic similarity. Thus, zebra finches organize their calls into categories and create a mental representation of the meaning of these sounds.