top of page

Slime Mold Learning

“Neither animal nor plant, the slime mold Physarum polycephalum is a large-scale single-celled organism that lives in damp forests. At a glance it may look like a splash of paint, but patient observation reveals it creeping across surfaces by oozing forward in fingerlike projections.

"Even though it doesn’t have a brain, the slime mold exhibits a simple form of learning by changing its behavior based on past experience. It also can pass what it learns to another slime mold simply by fusing with it for a couple of hours.



“Scientists discovered this by giving different slime molds a chance to creep across a tiny bridge made of salt (which they usually avoid) to reach a food reward. A group of slime molds was taught to cross a bridge without salt. Next, half of those slime molds were exposed to a bridge with salt. They were repelled at first, but eventually crossed anyway. The other half were not exposed to a salt bridge.

“When both groups were later given a chance to cross a salt bridge, the slime molds that had experience with a salt bridge traveled across the “yuck” to get to the “yum” more quickly than the others. Then, when a slime mold that had learned to tolerate the salt in order to reach the treat merged with another slime mold, the second slime mold also readily crossed the salt bridge—even after being separated from its partner—as long as the two had been together longer than an hour and had formed a connecting structure between them.

Is there a lesson for humans in slime mold learning? An hour of being together led to a transfer of knowledge and a beneficial choice based on that knowledge.


Might you talk for an hour with a friend who denies climate change about your understanding of climate change? Might this change your friend’s understanding and behavior as well as confirm your commitment to sharing what you know with others?

bottom of page