BIOLOGY Volume 2 - A Guide to General Biology - 2004

17. COORDINATION AND REGULATION IN ANIMALS

17.8. Innate Behavior

17.8.2. Instincts

Instincts are complex, innate, stereotyped patterns of behavior triggered by specific environmental changes and vital to an Organism's survival. They are species-specific and differ from unconditioned Reflexes by a significantly higher degree of complexity. Nobel laureate Konrad Lorenz, recognized for his foundational contributions to ethology, defined instincts as "innate species-specific action patterns."

Instincts predominate in invertebrates, such as insects, whose short life cycles leave no time for trial-and-error learning. By equipping the organism with a ready-made repertoire of behavioral responses, instincts enable both insects and vertebrates to use Nerve Cells efficiently. These responses are passed down from generation to generation and, having successfully stood the test of natural Selection, clearly contribute to the preservation of species.

However, despite being genetically programmed, instincts—like any other anatomical, biological, physiological, or behavioral traits of an organism—are influenced by the environment and undergo modification in response to environmental changes. Consequently, no behavioral response can be regarded as purely instinctive (innate) or purely acquired (i.e., shaped by life experience); any of the forms of behavior described here, whether seemingly purely instinctive or purely acquired, depend on both factors. Some researchers prefer to use the term species-specific behavior instead of "instinctive," and individually-specific behavior instead of acquired. Regardless of the terminology used, THE PRINCIPLE OF interaction between heredity and environmental conditions remains valid. This was convincingly demonstrated by Professor Thorpe in his studies of chaffinch song. He found that chaffinches raised by their parents in the wild, as well as those raised in isolation from parents or deafened since hatching, produce sounds that the human ear perceives as typical chaffinch song. However, spectrograms revealed that their song is merely rudimentary. The reason is that parent-reared chaffinches listen to the song of their parents and other members of the same population, developing a vocal pattern similar to that of the older birds. In other words, they acquire a specific "local dialect." The songs of deaf or captive-reared birds remained rudimentary, demonstrating that environmental conditions can significantly modify instinctive behavior.