no brain smarts

Physarum Polycephalum can learn even without a brain !

1 of 6 : slime mold helps to reveal threads of cosmic web

What is intelligence? The definitions vary, but all infer the use of grey matter, whether in a cat or a human, to learn from experience. Researchers from Belgium and France sought to demonstrate "habituation learning" in a brainless organism. A slime made up of independent, single cells, they found, can "learn" to avoid irritants despite having no central nervous system. "Tantalizing results suggest that the hallmarks for learning can occur at the level of single cells," the team wrote in a paper published in the journal Proceedings of the Royal Society B.

Updated: March 19th 2020: Astronomer Joseph Burchett and computer scientist Oskar Elek, both of the University of California, Santa Cruz
(Go Slugs!) and colleagues just last week adapted a computer method for producing slime mold–like patterns so that, instead of food sources, it could connect more than 37,000 known galaxies sprinkled throughout space. Surprisingly, that technique reproduced the kinds of structures seen in computer simulations of the cosmic web, scientists report March 10 in the Astrophysical Journal Letters.
( side note: Banana Slugs have no Known Predators! )

Slime mould takes no chances, it creates backup routes to its food supply forming a better United States interstate system.

Slime molds look gross and... not smart, but they definitely seem to communicate and plan even without neurons.

ARE SLIME MOULDS LIVING MEMRISTORS?

https://arxiv.org/abs/1306.3414

People knew resistor, capacitor and inductor for more than 200 years. However mathematician Leon Chua predicted the need for another fundamental circuit element called memristor in 1960. Despite the efforts of may scientists and engineers this device remain unrealizable for decades.

Finally in 2006, R. Stanley and his team from HP research lab crack the mystery.

What Is A Memristor? Alex Nugent gives a quick explanation of what a memristor is by first explaining what resistance and conductance is. He then talks about Dr. Chua's "if it's pinched it's a memristor" and shows what a typical hysteresis loop looks like.