What is meant by instinct?

Instinct refers to inherent, unlearned behaviors that organisms are born with, which occur naturally in response to specific stimuli. These behaviors are automatic and often crucial for survival, such as a bird building a nest or a baby grasping a finger. This concept aligns closely with the idea of "second nature," as these actions are not typically subject to conscious control or learning processes. Instead, they manifest instinctively, guiding animals and humans in certain situations without needing prior experience or instruction. Other options like a learned behavior, a reflex action, or a conditioned response involve different processes of learning and adaptation, whereas instinct is innate and fundamental to the species' biology.