WEBVTT - How Can Slime Mold Think Without a Brain?

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<v Speaker 1>Welcome to Brainstuff, a production of iHeartRadio, Hey Brainstuff, Lauren

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<v Speaker 1>Bolebon here. For a long time, nobody understood slime molds.

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<v Speaker 1>To be clear, no one really understands them now either,

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<v Speaker 1>But scientists now know that these pulsating piles of jelly

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<v Speaker 1>found on rotten logs in the forest are not fungi,

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<v Speaker 1>but are in fact more closely related to amieba's And

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<v Speaker 1>though there's nary and neuron in a slime mold's entire

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<v Speaker 1>gelatinous body, they seem to be able to solve relatively

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<v Speaker 1>complex problems. There are over nine hundred species of slime

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<v Speaker 1>molds living in the soils, leaf litter, and rotten logs

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<v Speaker 1>of this planet and other appropriately damp and humid areas

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<v Speaker 1>like maybe your bathroom. A Researchers have found a slime

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<v Speaker 1>mold cast an amber dating back at least one hundred

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<v Speaker 1>million years that remains entirely unchained from one you could

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<v Speaker 1>find today. A slime molds in general, though, have probably

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<v Speaker 1>been squishing their way around Earth for around a billion years.

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<v Speaker 1>It's possible that they're one of the first multicellular ish

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<v Speaker 1>organisms created by single cells joining and working together. Slime

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<v Speaker 1>molds are a really diverse group. They can appear in

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<v Speaker 1>any color except true green, a being that they lack chlorophyll.

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<v Speaker 1>Some called cellular slime molds live mostly as a single cell,

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<v Speaker 1>but may collect with others in a swarm in response

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<v Speaker 1>to chemical signals like food shortage or gotapprocreate now. Others,

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<v Speaker 1>called plasmordial slime molds, spend their entire lives as one

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<v Speaker 1>humongous organism enclosed in a single membrane. These are what

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<v Speaker 1>happen when thousands of single cells meet up and fuse together.

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<v Speaker 1>Either way, Once the cells of a slime mold are

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<v Speaker 1>in a collective, they can network and share resources. Slime

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<v Speaker 1>molds can form up in the shape of delicate lattices

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<v Speaker 1>or bulbous masses. They can remain microscopic or form collectives

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<v Speaker 1>ten feet long or longer now that's about three meters.

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<v Speaker 1>Given the motivation of, for example, finding food, those collectives

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<v Speaker 1>are capable of crawling like worms, towards a source of

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<v Speaker 1>nutrients or light, where nutrients are more likely to be.

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<v Speaker 1>The thing all slime molds have in common is their

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<v Speaker 1>life cycle, loosely resembling that of a fungus, which is

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<v Speaker 1>why taxonomists lump them in the fungi kingdom for so long. Basically,

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<v Speaker 1>when they vacuumed as much food out of their environs

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<v Speaker 1>as they can, they turn their bodies into clusters of

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<v Speaker 1>spore packets, usually on stalks and sometimes wildly colored, called sporangia.

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<v Speaker 1>These fruiting bodies disperse a fine mist of spores into

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<v Speaker 1>the air, which germinate wherever they fall. The single celled

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<v Speaker 1>organisms that spring from these spores start the slime mold

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<v Speaker 1>life cycle over again. For the article, this episode is

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<v Speaker 1>based on How Stuff Works. Spoke by email with Tanya Laddie,

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<v Speaker 1>who studies slime molds in the School of Life and

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<v Speaker 1>Environmental Sciences at the University of Sydney. She said, we

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<v Speaker 1>still know very little about the ecology of wild slime molds.

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<v Speaker 1>For example, how they interact with other organisms and what

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<v Speaker 1>role they play in ecosystems is still somewhat mysterious. A

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<v Speaker 1>Lattie studies cognition in both slide molds and insects, and

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<v Speaker 1>though we don't give insects much credit for their intelligence,

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<v Speaker 1>with slime molds, the already tricky concept of cognition gets

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<v Speaker 1>even weirder. Alattie said, slime molds and social insects are

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<v Speaker 1>both decentralized systems, where there is no leader in charge

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<v Speaker 1>of decision making. However, in the case of insects, each

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<v Speaker 1>individual operates both at the india visual level they have brains,

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<v Speaker 1>and at a collective level in slime molds, it's much

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<v Speaker 1>harder to even define what an individual is. We humans

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<v Speaker 1>rely on our brains for cognition, but even without a

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<v Speaker 1>giant brain such as ours, other animals do have the

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<v Speaker 1>ability to reason, learn, plan, and solve complex problems. A take,

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<v Speaker 1>for instance, the octopus, a cephalopod closely related to clams

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<v Speaker 1>and snails. It has a brain, but most of its

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<v Speaker 1>neurons are spread throughout its squishy body, mostly in its arms. Still,

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<v Speaker 1>an octopus has an undeniable intelligence. It can learn how

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<v Speaker 1>to open new kinds of containers to get snacks. It

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<v Speaker 1>can tell the difference between humans who are dressed identically,

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<v Speaker 1>or even make an escape from a tank, out a

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<v Speaker 1>drain pipe and back into the ocean. But this impressive

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<v Speaker 1>cognitive functioning bears no physiological relation ship to hours. The

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<v Speaker 1>neural processing equipment of an octopus evolved basically completely separately

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<v Speaker 1>from ours because our evolutionary lineages separated over four hundred

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<v Speaker 1>and sixty million years ago, but slime molds don't have

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<v Speaker 1>brains or even anything that resembles a neuron. There's a

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<v Speaker 1>lab friendly slime mold species named Physarum polycephalum, which means

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<v Speaker 1>many headed slime mold, though it's been affectionately nicknamed the

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<v Speaker 1>blob by researchers. It's bright yellow in color and can

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<v Speaker 1>move in gloopy filaments that look a bit like fans

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<v Speaker 1>of coral Researchers found that it can solve mazes. When

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<v Speaker 1>scientists place food at the end of a maze, the

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<v Speaker 1>mold will extend tendrills down different corridors and back out

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<v Speaker 1>of dead ends until it finds the food, all within

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<v Speaker 1>just a few hours. So while the process of learning

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<v Speaker 1>is completely different in a slime mold versus an octopus

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<v Speaker 1>versus a human, in each case, the outcome can look

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<v Speaker 1>basically the same. One type of learning slime molder capable

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<v Speaker 1>of is habituation. You do this too. You can get

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<v Speaker 1>used to the temperature of a cold lake after a

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<v Speaker 1>few minutes, or to the initially unpleasant buzzing sound of

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<v Speaker 1>a fluorescent light in a room. Your brain helps you

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<v Speaker 1>ignore the annoying sensation of the cold or the noise,

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<v Speaker 1>and similar to humans, the aforementioned blob can habituate to

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<v Speaker 1>environments and chemicals that it doesn't love acidic, dusty, dry,

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<v Speaker 1>salty places, or chemicals like caffeine or quinine if it

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<v Speaker 1>means it's going to get rewarded for putting up with it.

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<v Speaker 1>And not only can slime mold habituate to less than

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<v Speaker 1>ideal circumstances if it means they'll be rewarded, they also

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<v Speaker 1>seem to be capable of memory. The blob, for example,

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<v Speaker 1>seems to be able to remember things. An experiment involving

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<v Speaker 1>slime molds the intentionally habituated to salt, a known repellent,

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<v Speaker 1>before going into a dormant period, showed that they remembered

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<v Speaker 1>how to become habituated to living in a very salty

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<v Speaker 1>environment after a year of lying dormant. They also seem

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<v Speaker 1>to be able to decide which direction to travel based

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<v Speaker 1>on food that they've encountered there before, and researchers are

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<v Speaker 1>still exploring slime mold's capacity for and mechanisms of processing information.

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<v Speaker 1>The hope is that by figuring out how a decentralized

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<v Speaker 1>intelligence like a slime mold functions, maybe we can learn

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<v Speaker 1>something from them. Today's episode is based on the article

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<v Speaker 1>Brainless Footless slime molds are Weirdly Intelligent and Mobile on

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<v Speaker 1>how stuffworks dot Com, written by Jesslin Shields. Brain Stuff

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<v Speaker 1>is production of iHeartRadio in partnership with how stuffworks dot

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<v Speaker 1>Com and as produced by Tyler Klang. Four more podcasts

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