Cardiac response of domestic chickens to hawk and goose models

The response of precocial birds to configurational stimuli has been a source of controversy for decades. In this experiment we measured cardiac response of domestic chicks to "hawk" and "goose" silhouettes. The chicks' heart rates varied more in response to the hawk model than to the goose model, suggesting that the hawk silhouette is a more fearful stimulus than that of the goose. Our data document the recognition of a configurational stimulus without prior, pertinent experience.