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takyon [soylentnews.org] writes:

This Brainless, Single-Celled Blob Can Make Complex 'Decisions' [livescience.com]

Tiny, brainless blobs might be able to make decisions: A single-celled organism can "change its mind" to avoid going near an irritating substance, according to new findings.

Over a century ago, American zoologist Herbert Spencer Jennings conducted an experiment on a relatively large, trumpet-shaped, single-celled organism called Stentor roeselii. When Jennings released an irritating carmine powder around the organisms, he observed that they responded in a predictable pattern, he wrote in his findings, which he published in a text called "Behavior of the Lower Organisms" in 1906.

[...] In the decades that followed, however, other experiments failed to replicate these findings, and so they were discredited. But recently, a group of researchers at Harvard University decided to re-create the old experiment as a side project. "It was a completely off-the-books, skunkworks project," senior author Jeremy Gunawardena, a systems biologist at Harvard, said in a statement [harvard.edu]. "It wasn't anyone's day job."

[...] "They do the simple things first, but if you keep stimulating, they 'decide' to try something else," Gunawardena said. "S. roeselii has no brain, but there seems to be some mechanism that, in effect, lets it 'change its mind' once it feels like the irritation has gone on too long."

A Complex Hierarchy of Avoidance Behaviors in a Single-Cell Eukaryote [cell.com] (open, DOI: 10.1016/j.cub.2019.10.059) (DX [doi.org])

Original Submission