Brittle starfish are very shy, small starfish. They have no brain but they do have nerve cords that are in each of their five arms which join a nerve ring near their mouth. The lead researcher, Julia Notar, at the Sönke Johnsen’s lab at Duke University discovered that these starfish can learn using classical conditioning. Each nerve cord acts independently but work together as a committee according to Notar.

The starfish were kept in an aquarium and fed their favorite food, shrimp, only when the lights were dimmed. The starfish learned to come out of hiding as soon as the lights were dimmed, even before they were fed when there was no evidence of food in the aquarium.

Notar pointed out, “They’re potentially able to expect and avoid predators or anticipate food because they’re learning about their environment.”

Sue’s Note: The fact that they can learn about their environment means that they have the ability to remember as well as learn, if you cannot remember, you cannot learn. There has been evidence for many years that people who receive organ transplants sometimes show evidence of the behavior, likes and dislikes of the donor as a result of cell memory in the organ. This seems to be connected to learning without a brain.  (https://pubmed.ncbi.nlm.nih.gov/31739081/)

Journal Reference:

1. Julia C. Notar, Madeline C. Go, Sönke Johnsen. Learning without a brain: classical conditioning in the ophiuroid Ophiocoma echinata. Behavioral Ecology and Sociobiology, 2023; 77 (11) DOI: 10.1007/s00265-023-03402-x

Cite This Page:

Duke University. “Brittle stars can learn just fine — even without a brain.” ScienceDaily. ScienceDaily, 29 November 2023. <www.sciencedaily.com/releases/2023/11/231129174214.htm>.