ABSTRACT
Diversity of animal behavior is often considered as a sign of intelligence: intelligent animal should exhibit more diverse behaviors, which makes an animal adapt to a wider variety of situations (e.g., Griffin, 2001). However, animals with relatively simple nervous systems can regulate their behaviors according to various situations. Reed (1996) suggested that complex nervous systems are not necessary for adaptive regulation of animals’ behaviors; animals should have acquired this capacity for behavior regulation before their nervous systems had evolved. If this is the case, diversity of animal behavior should be reproducible with a parsimonious model of a mechanism common to animals with any level of complexity of nervous systems. Such a model should be constructed without using the terms of neural network theory, but with the terms of functionalism, e.g., ecological psychology.
