Abstract: Whether animacy perception has been embedded as a cognitive mechanism during evolution, as an adaptive outcome of life itself, is one of the central issues in current research on biological motion. The life detector hypothesis (LDH) focuses exclusively on dynamic cues, thereby addressing only a subset of animacy information processing. Given that static cues in the natural world can also elicit animacy perception, it is necessary to extend and substantiate this foundation by proposing and arguing for an animacy detectors hypothesis (ADH). This posits that cognitive agents possess an embedded core cognitive module— a sensory filter attuned to the intrinsic features of living organisms, This filter processes both dynamic and static cues to perceive external objects in the environment as possessing characteristics of biological motion. This mechanism provides the most fundamental and essential cognitive foundation for higher-level social cognition and its development. Converging evidence from ontogeny, comparative psychology, evolutionary biology, intersubjective factors (e.g., experience, development, level of awareness, and cross-modal interactions), and environmental influences (e.g., social interaction and gravitational shaping) has increasingly supported the possibility that the life detector is embedded. However, challenges remain regarding its embedded nature, such as questions concerning the preference for animacy. Future research should place greater emphasis on how the embedded mechanisms of the life detector are acquired, the processing stages involved, the role of multisensory information in animacy perception, and the deeper neural and cognitive mechanisms underlying these processes. Moreover, impairments in animacy perception observed among children with various types of neurodevelopmental disorders may serve as potential biological markers of such conditions.

Key words: biological motion, animacy perception, life detector, animacy detector, embeddedness, core knowledge