Unraveling the riddle of cognition

Brains are not required when it comes to thinking and solving problems – simple cells can do it. All intelligence is really collective intelligence, because every cognitive system is made of some kind of parts.

It turns out that regular cells – not just highly specialised brain cells such as neurons – have the ability to store information and act on it. Now it was shown that the cells do so by using subtle changes in electric fields as a type of memory. These revelations have put the biologist at the vanguard of a new field called basal cognition. Researchers in this burgeoning area have spotted hallmarks of intelligence- learning, memory, problem-solving – outside brains as well as within them.

The birth of cognition

Until recently, most scientists held that true cognition arrived with the first brains half a billion years ago. Without intricate clusters of neurons, behaviour was merely a kind of reflex. But  several researchers believe otherwise. deny that  They don’t deny brains are awesome, paragons of computational speed and power. But they see the differences between cell clumps and brains as ones of degree, not kind. In fact they suspect that cognition probably evolved as cells started to collaborate to carry out the incredibly difficult task of building complex organisms and then got souped-up into brains to allow animals to move and think faster.

That position is being embraced by researchers in a variety of disciplines, including roboticists such as Josh Bongard, a frequent collaborator who runs the Morphology, Evolution, and Cognition Laboratory at the University of Vermont. “Brains were one of the most recent inventions of Mother Nature, the thing that came last,” says Bongard, who hopes to build deeply intelligent machines from the bottom up. “It’s clear that the body matters, and then somehow you add neural cognition on top. It’s the cherry on the sundae. It’s not the sundae.”

Psychological studies show that people have very different concepts in their minds for most words. Even simple words like “penguin” conjure varying images in many people’s minds. So it makes sense that for more complicated and nuanced topics like climate change, a shared understanding is rare. Kris De Meyer, a neuroscientist at University College London found in studies that the concepts of “risk,” “uncertainty” and “threat” (all terms used in the climate discussion) mean very different things to people. Such differences are underpinned by differences in how the brain represents concepts, a process influenced by politics, emotion and character, according to neuroscience research.

Why this matters

This phenomenon may explain why climate scientists struggle to get their messages across to the public and policy makers, and why big financial organisations underestimate the threats of climate change. Terms can even differ from one discipline to another. For example, the term “risk” to an economist is an estimate of probability of a particular outcome occurring. But climate scientists use “risk” to describe negative consequences of warming global temperatures.

Apes, dogs, dolphins, crows and even insects are proving more savvy than suspected. In his 2022 book The Mind of a Bee, behavioural ecologist Lars Chittka chronicles his decades of work with honeybees, showing that bees can use sign language, recognize individual human faces, and remember and convey the locations of far-flung flowers. They have good moods and bad, and they can be traumatised by near-death experiences such as being grabbed by an animatronic spider hidden in a flower. (Who wouldn’t be?)

But bees, of course, are animals with actual brains, so a soupçon of smarts doesn’t really shake the paradigm. The bigger challenge comes from evidence of surprisingly sophisticated behaviour in our brainless relatives. “The neuron is not a miracle cell,” says Stefano Mancuso, a University of Florence botanist who has written several books on plant intelligence. “It’s a normal cell that is able to produce an electric signal. In plants almost every cell is able to do that.”

Smart plants

On one plant, the touch-me-not, feathery leaves normally fold and wilt when touched (a defence mechanism against being eaten), but when a team of scientists at the University of Western Australia and the University of Firenze in Italy conditioned the plant by jostling it throughout the day without harming it, it quickly learned to ignore the stimulus.

Most remarkably, when the scientists left the plant alone for a month and then retested it, it remembered the experience. Other plants have other abilities. A Venus flytrap can count, snapping shut only if two of the sensory hairs on its trap are tripped in quick succession and pouring digestive juices into the closed trap only if its sensory hairs are tripped three more times.

These responses in plants are mediated by electric signals, just as they are in animals. Wire a flytrap to a touch-me-not, and you can make the entire touch-me-not collapse by touching a sensory hair on the flytrap. And these and other plants can be knocked out by anaesthetic gas. Their electric activity flat-lines, and they stop responding as if unconscious.

Plants can sense their surroundings surprisingly well. They know whether they are being shaded by part of themselves or by something else. They can detect the sound of running water (and will grow toward it) and of bees’ wings (and will produce nectar in preparation). They know when they are being eaten by bugs and will produce nasty defence chemicals in response. They even know when their neighbours are under attack: when scientists played a recording of munching caterpillars to a cress plant, that was enough for the plant to send a surge of mustard oil into its leaves.

Plants are a relatively easy case – no brains but lots of complexity and trillions of cells to play with. That’s not the situation for single-celled organisms, which have traditionally been relegated to the “mindless” category by virtually everyone. If amoebas can think, then humans need to rethink all kinds of assumptions.

Yet the evidence for cogitating pond scum grows daily. Consider the slime mould, a cellular puddle that looks a bit like melted Velveeta and oozes through the world’s forests digesting dead plant matter. Although it can be the size of a throw rug, a slime mould is one single cell with many nuclei. It has no nervous system, yet it is an excellent problem solver.

When researchers from Japan and Hungary placed a slime mould at one end of a maze and a pile of oat flakes at the other, the slime mould did what slime moulds do, exploring every possible option for tasty resources. But once it found the oat flakes, it retreated from all the dead ends and concentrated its body in the path that led to the oats, choosing the shortest route through the maze (of four possible solutions) every time. Inspired by that experiment, the same researchers then piled oat flakes around a slime mould in positions and quantities meant to represent the population structure of Tokyo, and the slime mould contorted itself into a very passable map of the Tokyo subway system.

When Audrey Dussutour of France’s National Center for Scientific Research placed dishes of oatmeal on the far end of a bridge lined with caffeine (which slime moulds find disgusting), slime moulds were stymied for days, searching for a way across the bridge like an arachnophobe trying to scooch past a tarantula. Eventually they got so hungry that they went for it, crossing over the caffeine and feasting on the delicious oatmeal, and soon they lost all aversion to the formerly distasteful stuff. They had overcome their inhibitions and learned from the experience, and they retained the memory even after being put into a state of suspended animation for a year.

Learning from the planaria

The planarian is nobody’s idea of a genius. A flatworm shaped like a comma, it can be found wriggling through the muck of lakes and ponds worldwide. Its pin-size head has a microscopic structure that passes for a brain. Its two eyespots are set close together in a way that makes it look cartoonishly confused. It aspires to nothing more than life as a bottom-feeder.

But the worm has mastered one task that has eluded humanity’s greatest minds: perfect regeneration. Tear it in half, and its head will grow a new tail while its tail grows a new head. After a week two healthy worms swim away.

Growing a new head is a neat trick. But it’s the tail end of the worm that intrigues Tufts University biologist Michael Levin. He studies the way bodies develop from single cells, among other things, and his research led him to suspect that the intelligence of living things lies outside their brains to a surprising degree. Substantial smarts may be in the cells of a worm’s rear end, for instance. “All intelligence is really collective intelligence, because every cognitive system is made of some kind of parts,” Levin says. An animal that can survive the complete loss of its head was Levin’s perfect test subject.

In their natural state planaria prefer the smooth and sheltered to the rough and open. Put them in a dish with a corrugated bottom, and they will huddle against the rim. But in his laboratory, about a decade ago, Levin trained some planaria to expect yummy bits of liver puree that he dripped into the middle of a ridged dish. They soon lost all fear of the rough patch, eagerly crossing the divide to get the treats. He trained other worms in the same way but in smooth dishes. Then he decapitated them all.

Levin discarded the head ends and waited two weeks while the tail ends regrew new heads. Next he placed the regenerated worms in corrugated dishes and dripped liver into the center. Worms that had lived in a smooth dish in their previous incarnation were reluctant to move. But worms regenerated from tails that had lived in rough dishes learned to go for the food more quickly. Somehow, despite the total loss of their brains, those planaria had retained the memory of the liver reward.

It appears that all life has the ability of thought in some form or another. Maybe sapiens is not the be all and end all. We haven’t done a very good job so far.