Are You Smarter Than A Slime Mold?

[music playing] This is a pretty simple maze.

It shouldn't be too hard for you to solve.

Of course, you're pretty smart.

You've got 86 billion neurons at your disposal.

You're a member of the most intelligent species on the planet.

[bam] But what if you were a pulsating wad of yellow goo?

I'm going to let my friend, Amy from Deep Look introduce you.

AMY: This is physarum polycephalum, a slime mold, which sounds like something you might find on stale bread.

But it's not a fungus.

It's a jelly-like protist.

You can think of it like one big cell holding millions of nuclei.

And they might not seem like much, but slime molds are smarter than they look.

Just watch.

JOE HANSON: This slime mold can solve mazes.

It does so by first exploring every path.

And then when it's found the food at either end it retracts any paths that don't connect the points.

Solving a maze involves remembering where you've been.

Where does a single celled ball of goo hold memories?

Physarum does this by leaving chemical trails to mark dead ends.

So it can remember where it's already explored.

When slime molds are presented with a maze that has more than one solution they'll even figure out the shortest one.

No matter the shape they'll almost always connect distributed food sources by the shortest path.

If that doesn't impress you, realize that once you start adding points mapping efficient networks is an incredibly complex problem that humans need big computers and complex math to solve.

This living ooze is redefining what it means to be intelligent.

They've even been able to map the rail system of Tokyo and the major highways of the United Kingdom.

Another kind of slime mold shows a different kind of smarts.

This is dictyostelium, a cellular slime mold.

Now instead of a creeping blob this slime mold lives most of its life as single free-living amoeba gulping up bacteria.

But when it runs out of food something amazing .

Happens AMY: One cell starts emitting a chemical.

This attracts other cells.

And once they join up those cells start emitting chemical pulses of their own.

This is called chemotaxis.

And the bigger the mass gets the stronger that signal, until eventually there's tens or hundreds of thousands stuck together.

These once free-living cells now cooperate like a multicellular organism, coming together like Voltron and moving in unison.

This slug travels farther and faster than any single cell could on its own.

It's about to undergo a second incredible transformation.

AMY: After the slug migrates away it flattens itself and begins to sprout.

A thin stalk grows out lifting a fruiting body into the air.

From here spores will be released to be collected by passing insects and carried to plentiful food.

What's amazing is the cells making up the stalk die.

They sacrifice themselves so other cells can live on.

It's not that different from what a weed plant does growing, dying off, and releasing the next generation into the wind.

But a plant lives its whole life is a multicellular organism.

These amoeba are separate individuals, yet they're acting for the benefit of others.

This is a principle called altruism.

It goes against what we might expect from natural selection that every individual wants to succeed and pass its own genes on.

But altruism suggests that helping the group that we're genetically related to can help the entire species survive.

We see this in animals hunting together, worker bees tending to the queen, meerkats standing guard over their dens, or chimpanzees sharing food.

But these slimy species especially challenge what we think of as intelligence.

Because so many of our preconceived notions don't fit what we see.

Anthropologist Jeremy Narby writes, "we struggle over words when the slime mold solves the maze, because our concepts don't fit the data.

It's not that nature lacks intelligence, but that our own concepts do."

What he means is any view of nature that puts humans in a separate category isn't a very good view of nature at all.

And if something as simple as a slime mold can solve problems, can come together and cooperate for the good of the group, it's a nice reminder-- AMY: --that if the goo can do it, so can we.

If you want to get an up close look at how slime molds move and how scientists are using that as inspiration for future robots, then follow me over to Deep Look.

And as always, stay curious.