Early researchers referred to predictable behaviors displayed by species as what?

The term "fixed action patterns" refers to predictable, instinctive responses exhibited by animals in certain situations. These behaviors are often consistent and species-specific, meaning that nearly all members of a species will display them in similar contexts, regardless of learning or environmental influence. Fixed action patterns typically occur in response to specific stimuli, leading to a routine sequence of actions that are hardwired into an animal's biology.

For example, a classic illustration of a fixed action pattern is the clutching reflex in birds, where a chick instinctively responds to a certain movement near the nest by pecking, whether the movement is from the parent or an object that mimics it.

While the other terms hold relevance in behavioral studies, such as habits (which are learned behaviors) and instincts (which refer broadly to inherent inclinations), fixed action patterns distinctly capture the idea of automatic and predictable behaviors that occur without prior learning, driven purely by the organism's genetic programming. This specificity aligns with the definitions and understanding of behavior in the field of ethology.