Why is it difficult to identify unlearned behaviors in highly evolved animals?

Identifying unlearned behaviors in highly evolved animals is difficult because the traditional dichotomy between "innate" (genetically programmed) and "learned" (experience-based) behavior is largely considered an oversimplification. In reality, all behaviors result from a complex, continuous interaction between an animal's genes and its environment.123

Several factors contribute to this complexity:

• Instinctive Learning: Many animals are genetically predisposed to acquire specific information at precise times, a phenomenon often called "instinctive learning". Because genes steer an animal to develop behaviors in certain ways, it is difficult to isolate what is purely unlearned versus what is an innate predisposition to learn.12
• Adaptive Specialization: Animals possess specialized learning mechanisms shaped by natural selection to solve specific environmental problems. These mechanisms are often so efficient and "machinelike" that they can be mistaken for blind instinct.14
• Developmental Interaction: An animal’s experiences during development can influence how its genes are activated, which in turn shapes subsequent behavior. Consequently, even behaviors that appear automatic or "fixed" often involve subtle modifications based on early environmental inputs or developmental stages.234

Ultimately, because genes and experience are inextricably linked, it is rarely possible to categorize a behavior as strictly innate or entirely learned.23