Signal detection, acceptance thresholds and the evolution of animal recognition systems

Nearly every biological interaction requires some kind of recognition. Recognition systems, therefore, play critical roles in discriminating among friends and foes in diverse contexts including self, mate, kin, predator-prey, and host-parasite interactions. Evolution should favour stringent recognition when mistakes are costly. Yet, both acceptance errors (e.g., accepting a parasitic cuckoo’s mimetic egg) and rejection errors (eliminating your own egg instead) are common. To examine how individuals balance these error-costs, behavioural ecologists have extensively applied a Signal Detection Theory framework. The central aim of our special issue was to bring together diverse biological perspectives, research themes, and participants to highlight accomplishments, to underline shortcomings, and to point towards future work in signal detection based concepts of recognition system theory and data.