The Molds of Intelligence

5 min readAug 1, 2021

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By Anwesha Banerjee (JB Scholar 2019)

Beauty and intelligence in unexpected forms- a few of the numerous slime mold species (Image credit: New York Times)¹

If someone asked me, ‘What makes us intelligent?’, I probably would have answered, ‘A developed brain’. Had the questioner been a protist, I would have been shocked at such an outrageous question from such a seemingly underdeveloped species. They don’t even have two cells, let alone a brain, and there they speak of intelligence! As a matter of fact, I was asked this question by a protist, one rainy afternoon when I came across slime molds — and was entranced by their beauty, elegance, intelligence and experience instantly. Digging deeper, every word I read redefined the question we really should be asking ourselves now,

Why are we intelligent? How and when did we become intelligent?

Introducing the slime molds

Earlier thought to be fungi due to their life cycles, slime molds (kingdom Protista, phylum Myxomycetes) have diverged from the evolutionary tree long before plants and animals — approximately 600 million to 1 billion years ago (whereas, the oldest known plant fossils date back to 420 million years ago). They have been classified into three groups: Myxogastria (plasmodial, or acellular molds), Dictyosteliida (cellular molds) and Protosteloids (amoeboid molds).

To researchers, they are one of the best model organisms, their morphology, metabolic functions, locomotory abilities, have been under study for more than three decades but not their intelligence.

Image 1: The Blob *(P. polycephalum)* at Paris Zoo exhibit, opened to the public on 19th October 2019 (Image credit: CNN)²

The first study on their intelligence was published in 2008, on acellular slime mold Physarum polycephalum and they have been doling out surprises ever since. Image 1 shows P. polycephalum (better known as the Blob), growing in peace at the Paris Zoo exhibit.

Fun Fact: Dictyostelium discoideum a species of cellular slime mold, farm their own food by seeding their choice of bacteria inside spore containing capsules and dispersing them when there is food shortage. Their ancestors are considered to be the first farmers, and colonisers of dry land.³

What can they (not) do?

Physarum exist as super-cellular, decentralized organisms (as multinucleate single cells) in forest beds and decaying plant matter, with over 720 sexes that can interbreed.⁴ They can reform if the cell body is torn apart, or exist independently as newly separated entities, or fuse separate cells to form one cell. They show a plethora of abilities — sensing light, smell, temperature, memorizing food locations by leaving venous slime tracks, figuring out the shortest paths to the food source, adapting to stress conditions like bright light, salt and high temperature (if exposed to over time) and can teach other non-exposed molds to adapt to those stress conditions as well. They have specific, ‘healthy’ food choices with optimum (1:2) carbohydrate and protein ratio.⁵

Image 2: The Tokyo railway map by *P. polycephalum* (Image credit: AAAS)⁸

They have an innate ability to learn, decide and adapt — as observed by ecologist and entomologist Tanya Latty, from Australia. In her experiments, Physarum chose food sources of varying qualities kept in different conditions of light and temperature, in a pattern suggestive of our decision making — an acute weighing of the pros and cons.⁶ They have solved mazes connecting as many as 37 points, with increasing efficiency in each attempt — exemplifying how fast they learn.⁷ The fact that their intelligence measures close to ours, if not more, came through when they mapped the transport systems of Tokyo, Canada, USA with their residual slime, within days, when oat flakes were placed on relative locations corresponding to big cities.⁸ They designed these networks faster than any human ever, that too without a nervous system. Image 2 shows the mapping of the Tokyo railway map by P. polycephalum.

Why we need them, but they don’t need us

“Plasmodial slime molds are superorganisms, meaning that their self-interest is inseparable from their collective interest. The same is true of us humans, only our society doesn’t realize it yet.”- Jonathon Keats ¹⁰

From evolutionary research to unbiased decision making for increasingly complex problems to bio processor powered artificial intelligence (as creative processors or memristors which are resistors with memory)⁹, slime molds are the resource we cannot make do without. They are legends who have survived every evolutionary obstacle and in the unique abilities scattered all across the phylum we have proof enough, even though we have just scratched the surface of their prowess yet. Whereas we, with our developed brains have been here for just 300,000 years, and are destroying every bit of this planet to survive.

Digging deeper, every word I read redefined the question we really should be asking ourselves now,

Why are we intelligent? How and when did we become intelligent?

References

To know more

there are lots and lots of others too!