How did Konrad Lorenz describe fixed action patterns?

Konrad Lorenz, a founder of ethology, defined fixed action patterns as a distinct type of innate, genetically determined behavior. He maintained that these patterns possess all the essential attributes of instinct.1

According to Lorenz, a fixed action pattern is characterized by the following:

• Stereotyped: It occurs in a highly similar fashion each time it is performed.12
• Species-specific: It is possessed by all members of at least one sex of a species.12
• Innate: It is genetically inherited and unlearned.1
• Internally controlled: Once triggered, the behavior runs its course without requiring further peripheral stimulation.1
• Triggered by specific stimuli: It is initiated by a specific external stimulus, known as a "sign stimulus" or "releaser".12

To explain the motivation behind these acts, Lorenz postulated the continuous internal generation of "action-specific energy." He suggested that this energy accumulates between performances and, upon reaching a certain threshold, drives the animal to perform the behavior. While his work was foundational, it faced criticism from other scientists, including Nikolaas Tinbergen, who questioned the model of distinct energy for each pattern.1