In a groundbreaking study, brainless creatures like brittle stars exhibit a remarkable ability to learn through experience, navigating their environment swiftly for survival. Lead researcher Julia Notar unveils their unique anatomy, emphasizing the absence of a traditional processing center.
(Photo : Duke University)
This time-lapse video shows a classical conditioning experiment Duke researchers conducted to see if brittle stars – which don’t have brains – could learn.
Functioning Without Brains
A recent study reveals that brainless creatures like brittle stars, devoid of a central processing unit, can acquire knowledge through experience. Interesting Engineering reported that this unique ability enables them to swiftly navigate their surroundings for escaping predators or locating food.
Lead author Julia Notar, conducting the research as part of her biology Ph.D. at Duke University under Professor Sönke Johnsen's supervision, explains the absence of a traditional processing center in these animals.
Rather than a conventional brain, these marine creatures possess nerve cords extending down each of their five flexible arms, ultimately converging to form a nerve ring near their mouth. The study suggests that this neural network is adequate for learning through associative mechanisms.
The independent functionality of each nerve cord, operating akin to a committee rather than a central authority, is a notable aspect of this learning process.
This mechanism involves classical conditioning, a concept introduced by Russian physiologist Ivan Pavlov in the late 19th and early 20th centuries. In classical conditioning, a neutral stimulus is paired with an unconditioned stimulus to produce a conditioned response.
Bridging the Gap
Over time, classical conditioning has evolved as a fundamental principle in behavioral psychology, providing valuable insights into both human and animal behavior. It serves as a comprehensive framework for understanding how associations between stimuli and responses develop through experiential learning.
Previous experiments with starfish had demonstrated the applicability of classical conditioning principles to their behavior. However, the majority of echinoderms, encompassing creatures like brittle stars, brainless sea urchins, and sea cucumbers, remained unstudied.
To bridge this scientific gap, researchers from Duke University conducted extensive studies involving 16 black brittle stars over a 10-month period. Half of the brittle stars underwent training where the lights were dimmed for 30 minutes before feeding, while the other half were exclusively fed under well-lit conditions.
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Initially, when the lights dimmed early in the experiment, all the animals, without exception, remained concealed. However, with time, the group of animals trained to feed in the dark established a robust connection between the absence of light and the availability of meals.
This behavioral shift occurred even before any food was introduced into the tanks, indicating their learned anticipation of meals during darkness.
According to Notar, this discovery challenges the perception of brittle stars as mere automated scavengers, likening them to little Roombas cleaning the ocean floor. Instead, they demonstrate the potential to anticipate and avoid predators or predict food availability, showcasing their ability to learn and adapt to their environment.
As published in Behavioral Ecology and Sociobiology, Notar aspires to unravel the mysteries of how these brainless creatures acquire and retain knowledge using a neurological system vastly different from our own.
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