Information theory in vertebrate stress physiology

Information theory has been applied productively across biology, but it has been used minimally in endocrinology. Here, we advocate for the integration of information theory into stress endocrinology. Presently, the majority of models of stress center on the regulation of hormone concentrations, even though what interests most endocrinologists and matters in terms of individual health and evolutionary fitness is the information content of hormones. In neuroscience, the free energy principle, a concept offered to explain how the brain infers current and future states of the environment, could be a guide for resolving how information is instantiated in hormones such as the glucocorticoids. Here, we offer several ideas and promising options for research addressing how hormones encode and cells respond to information in glucocorticoids. Information theory has been applied productively in many biological subdisciplines but it has only just begun to be applied to stress endocrinology.Information theory has been critical to the development of neuroscience as a key subdiscipline and we expect the same for endocrinology.Integrating information theory to stress biology will allow developing fully cohesive, quantitative models of stress focused on relationships among traits, trait categories, and trait–environment interactions.