In neural system, the nociceptor normally exhibits important characteristics such as pain threshold, memory of prior injury, and sensitization/desensitization. [7,8] Pain perception usually includes nociceptive sensation, pain intensity, pain unpleasantness, and cognitive behavior, which is an unconditional driving force for the behavioral response to stop pain. [9] Humans may adopt pain-related fears, psychological distress, and other physical responses to avoid the potential dangers. Therefore, the exploration of novel artificial nociceptors is of great importance for nextgeneration intelligence equipment. In the past few years, nociceptor have been emulated by the emerging devices with two-terminal or three-terminal structures. [10][11][12] Although these works are very promising, this artificial nociceptor equipment usually receive electric signals or light signals caused by damaging forms of energy from the environment. At present, an artificial nociceptor with strong sensitization characteristics is still lacking.Interestingly, several reports have revealed that the pain conditioning phenomenon triggered by Pavlovian training is the basis of more advanced pain-perceptual behaviors, including how the brain learns, subsequently detects, and responds to threats. [13,14] Moreover, Pavlovian fear conditioning is an important mechanism for learning from the pain stimulus and protecting themselves from the outside dangers. [15][16][17][18] Therefore, the realization of a neuromorphic device with the strong pain-to-fear perceptual abilities by Pavlov's learning rule may open a new avenue in the emerging bionic applications. However, such a device still remains to be explored till now.In this paper, a pain-to-fear perceptual device can be successfully demonstrated using organic-inorganic hybrid electrolyte-gated MoS 2 transistor. Based on the unique ion migration mechanism in polymer electrolyte, our bionic transistor can realize several key features of pain perception, such as pain threshold, sensitization, desensitization, and so on. Moreover, a clear transition from pain-to-fear recognition by Pavlovian training can be finally achieved. Our organic-inorganic hybrid transistor cannot only achieve the classical pain perception but also exhibit a recognition transition from pain to fear. Consequently, this designed pain-perceptual device may be very promising for the next generation of intelligence cognitive electronics.The pain perception system is of great importance for the human body to perceive noxious stimuli in external environment and make an appropriate reaction. Therefore, the hardware realization of nociceptors using emerging solid-state device is of great importance toward the next-generation intelligent electronic devices. However, at present, the pain recognition with threshold regulation is still very lacking by using the solid-state device. Herein, a novel pain-perceptual device based on organic-inorganic hybrid MoS 2 transistor is fabricated by using polyvinyl alcohol-based electrolyte. The key char...