Can brainless animals think?

Creatures that lack brains, such as jellyfish, sea stars, sea urchins, and sea anemones, can still exhibit complex behaviors like learning and reacting to their environment. While they do not have centralized brains, many of these animals possess diffuse nerve nets, which are interconnected networks of neurons distributed throughout their bodies. These nerve nets can process sensory information and produce coordinated motor responses, enabling them to capture prey, sense danger, and navigate. Experiments have demonstrated that these "brainless" animals can learn from experience. For instance, sea anemones can be trained to associate a light stimulus with a mild shock, causing them to retract at the mere sight of the light. They can also adapt their behavior, such as reducing territorial aggression after repeated encounters with identical neighbors. Box jellyfish have shown the ability to learn to associate visual cues with physical sensations, aiding in obstacle navigation. The question of whether these animals can "think" is complex and depends on the definition used. While basic learning and behavioral changes can be considered forms of cog... download the app to read more