No brain, no problem? New research shows jellyfish can learn

Researchers trained jellyfish to avoid obstacles in a tank
The jellies were able to learn despite not having a centralized brain
The study could change how scientists look at learning and evolution

Updated: Sep 25, 2023 / 02:28 PM CDT

TOPSHOT – This picture taken on August 21, 2019 in Paris, shows jellyfish displayed in a tank at the Aquarium of Paris. – At the Aquarium of Paris, the excrement of roaches, goldfish and sturgeons feed tomatoes and peppers, to the surprise of visitors. Aquaponic systems are closed circuits, where the fish, via their excrement rich in nitrogen, create fertilizer for the plants, which absorb these nitrates and filter the clean water back to the fish. (Photo by BERTRAND GUAY / AFP) (Photo credit should read BERTRAND GUAY/AFP via Getty Images)

(NewsNation) — Jellyfish have surprisingly complex nervous systems capable of learning, according to new research, despite not having a brain.

The research was published in Current Biology and could shed new light on the evolutionary aspect of learning.

Unlike more advanced species, jellyfish don’t have brains and instead have radially distributed
nervous systems. The new findings challenge assumptions that a central brain is needed for advanced learning.

Researchers trained Caribbean box jellyfish, scientifically known as Tripedalia cystophora, to see if the creatures could learn to dodge obstacles. The species of jellyfish used in the study have a complex visual system with 24 eyes which the jellies use to navigate in their natural habitat of mangrove swamps.

Scientists created a round tank with gray and white stripes to mimic mangrove roots. Initially, the jellies swam close to the stripes and bumped into them but over the course of the experiment, the jellyfish quadrupled the number of successful efforts to dodge obstacles.

The results indicate jellyfish can learn using vision and experience, despite not having any kind of centralized brain for processing. Researchers reported the jellies learned very quickly, suggesting some sort of short-term memory, although it’s not clear how long the jellyfish might retain what it’s learned.

Scientists were unable to determine how the jellies processed and coordinated information without a brain. It is one question researchers hope to examine in future studies.