Results

As you know, animals with at least minimally developed mental abilities can easily associate a stimulus with a response and change their behavior. For example, if you find that touching a hot stove causes pain, you will likely change your behavior in the future to prevent this from happening again.

The ability to remember such things is believed to occur during the development of the nervous system, which regulates the strength and plasticity of synapses in the brain. But not all animals have brains. Sea anemones and jellyfish have a decentralized neural network.

• During the experiment, the authors of the new study lightly shocked the sea anemone with the current while turning on the light.
• In response to a painful stimulus, sea anemones retract their tentacles.
• Pretty quickly, sea anemones learned to retract their tentacles only in response to turning on the light.
• If this is a fairly obvious response for more complex organisms, then something different can be expected from intestinal worms – such a reaction has puzzled scientists.

It is still unclear whether sea anemones have the same kinds of neuromodulators (such as serotonin or dopamine) that we do, or whether their ability to produce behavior in response to stimuli has evolved independently.

Professor Simon Sprecher of the University of Freiburg, who worked on the research, says this has led to more research on brainless animals and the phenomenon of brainless learning in general.