What if plants are smarter than we think - a lot smarter? That's the central premise for an essay, published in The Paris Review by New York-based writer and editor Cody Delistraty. He takes research from scientists going back to Darwin suggesting plants can learn and some can tell the difference between destructive animal predators and selective human pruners. Can plants adapt using telepathy or a swarm mentality? If so, could they fight climate change on their own?
Delistraty tells Jim Mora he became interested in writing about the subject after a study suggested plants could have memory. In the study, a plant was repeatedly dropped from a safe distance. At first, it curled its leaves into a defensive posture, but after a realising there was no danger, stopped reacting - indicating it remembered and learned from experience.
He acknowledges that a lot of claims about plant intelligence have been outlandish.
“That’s one of the issues with the current science. There was a former CIA officer who was doing a lot of research in the mid-century in America, claiming that plants could sense killers.
“He would have someone kill a plant and then walk into the room and would have a device hooked up to other plants and he claimed that those devices would go off in such a way that implied the plants realised they had a plant killer in their midst.”
Delistraty says these debunked studies have caused a stigma around the topic of plant intelligence.
However, he points to compelling evidence such as plants that can send out poison to animals who might be eating a branch of a tree, and a swarm mentality where plants will help keep a dying plant alive.
“It goes beyond that too. There’s a study from a decade ago with four searocket plants were put in the same pot; they shared their resources and moved their roots to accommodate the others which is not what you’d expect from an evolutionary perspective, you’d expect a winner takes all type of approach – you wouldn’t expect this, dare I say, thoughtful approach to dealing with other plants.
“Crucially, a lot of these plants we’ve seen are able to adapt within their lifetime. They’re able to make changes within a single lifespan, which is not what you’d normally expect evolutionarily – you’d expect these things to be done over many generations.”
Part of the problem is that our language is so human-based that we risk anthropomorphising plants.
Another intriguing thing found in plants is that they respond differently to interactions. For instance, with some trees, if a human breaks off a branch, it gives out healing responses. But if an animal starts gnawing on a tree branch, it sends out a poison.
“It’s difficult to characterise these plants as ‘learning’ or ‘remembering’. It’s so difficult and nuanced and it becomes a semiotic question of ‘what is intelligence’, ‘what is thinking’, ‘what is learning’, ‘what is memory’.
“Plants are actually opening – or have a capacity to open – humans to a new way of seeing themselves, a new way of philosophising, of viewing our own existence, especially compared to plants which, obviously, make up so much of the biome and have been around for so much longer than us humans.”