Liberal Arts Blog — Wednesday is the Joy of Science, Engineering, and Technology Day
Today’s Topic — “Can Slime Mold Think?”
They don’t have eyes, but they can detect mass at a distance. They can tell time. They can remember things. They can solve problems. Who needs a nervous system? Today, a few notes from an intriguing article that appeared in the most recent edition of Harvard Magazine on the subject of the unicellular slime mold, Physarum polycephalum. Experts — please chime in. Correct, elaborate, elucidate.
TIME KEEPING, PROBLEM SOLVING, MEMORY
1. “If flown with cold air on the first of every hour, by the third hour, they’ll retract just before the cold snap.”
2. “They complete complex mazes in search of oatmeal. They can even recreate the hyper-efficient Tokyo subway map when oat flakes — their favorite food — stand in for population centers.”
3. They remember food sources.
(Physarum polycephalum on a log)
THE DETECTION OF MASS DISTRIBUTION AT A DISTANCE — the analogy of being lost in a desert, TRP channels, and the blind person on the trampoline and spider analogies
1. “Even more than the total mass of the objects, the slime mold reacted to how much of the horizon the objects occupied. It repeatedly preferred objects spread along the horizon as opposed to those stacked at a single point.”
2. “The scientists do not know exactly why slime mold privilege this factor, but it might be intuitive: “If you’re lost in the desert at night and you see three dispersed points of light versus a single bright one, you’ll probably head toward the three lights. You’d think maybe it was a city, that there might be more going on there.”
3. “Human cells use proteins called TRP channels for mechanosensation. In much the same way that a blindfolded person on a trampoline can sense if other people are on it, TRP channels help the slime to detect faraway objects.”
NB: “It’s like how spiders can sense their prey in their net based on vibrations and tension even without looking around…When researchers disrupted the slime mold’s TRP channels both mechanically (by shaking the petri dish) or chemically (by injecting it with a TRP-channel blocking drug), Physarum lost its mass-sensing ability and only selected the high-mass area about 11 percent of the time.”
TRP CHANNELS ARE LIKE THE EYE’S RETINA — how does the message get processed?
1. This is still a mystery. What is clear is that the slime do not have a brain and do not have neurotransmitters.
2. The slime mold has a different form of intelligence.
3. “Yet we share something with it, which is the ability to map out the world we live in, make decisions and try to do what we like.” (Michael Levin, professor, Tufts University)
NB: “Cognition is all around you. It really is everywhere. And really, it’s not just for furry, brainy things.” (Levin)
A LINK TO THE LAST THREE YEARS OF POSTS ORGANIZED BY THEME:
Please share the coolest thing you learned this week related to science, engineering, or technology. Or, even better, the coolest or most important thing you learned in your life related to science and engineering.
This is your chance to make someone else’s day. Or to cement in your mind something that you might otherwise forget. Or to think more deeply about something dear to your heart. Continuity is key to depth of thought.