As you all know, I am a giant Michael Pollan fan, and you should be too. Pollan, author of The Omnivore’s Dilemma and The Botany of Desire, recently published a piece in “The New Yorker” examining plant intelligence and the inherent controversy in that seemingly paradoxical terminology. According to Pollan, plant intelligence as a widely accepted field of inquiry in the scientific community could help us understand a great deal about our own brains, and dissolve conservative, archaic definitions we humans have of our fellow earth inhabitants.
The sapling of this growing jungle of ideas was the 1973 book The Secret Life of Plants by Peter Tompkins and Christopher Bird (that’s where, says Pollan, we got ideas such as plants’ interest in classical music). In 2006, some years later (and some controversy later), plant biologist Stefano Mancuso and five other scientists penned a paper, utilizing the term “plant neurobiology,” in Trends in Plant Science. Since then, those researchers, among others, have been fighting to get many scientists on their side, but many balk at the idea of plants having cognition that resembles our own (a contention that really only exists on that opposing side).
Pollan interviews many researchers and presents us with a startling strain of behaviors. Apparently, plants have kind of a webby brain, in that their roots can sense all sorts of jazz even before touching it. Plants have senses that weirdly mirror our own, and can sense competition of other plants, using a staggering array of toxins to communicate and even defend themselves. For instance, some plants send chemical signals to wasps when caterpillars are munching on them, in effect calling for reinforcements (Pollan brings this in to highlight our overindulgence in pesticide use).
One of the coolest researchers Pollan encounters in his expose on plant intelligence is Monica Gagliano, who spoke at a conference about the mimosa pudica, a plant that has reactions in human-perceivable time (like venus flytraps when bugs land on them). According to her, plants such as these can learn and remember stuff. Her experiment was to drop these plants certain distances and see their reactions, and then run the same plants through other trials. The plants reacted to danger (pulling in their leaves) at being dropped, didn’t react to other less threatening stimuli, and then remembered the original danger drop. Gagliano, though, was ill received by the community because she called this behavior “learning”.
Of course, you’d have to read Pollan’s article to get the most in depth explanations, and maybe even delve into some of the research cited. What you take away, though, is even more interesting than the individual behaviors. Scientists, according to Pollan, are hard nuts to crack, and become nervous at the use of metaphor or artistic expression, but some of that may be necessary in understanding plants. Plants lack neurons, yes, but have a certain level of consciousness (the ability to solve a problem in an optimal fashion), a concept that is threatening to human intelligence. Some of the researchers mentioned that the definition itself of intelligence needs to come under harsher scrutiny, and that plants are by no means a sub-creature in the broad mess of living things on the planet.
Marusco told Pollan that plants may be constant reminders of our own deficiencies. If we were to disappear, plants would be just as content as before, but we rely on their green deliciousness to survive. Plants have incredible communicative networks consisting of crazy numbers of different chemicals, and are capable of biological functions we can hardly dream of. Humans think that our big brains make us so special, but plants have brains in their roots, and enjoy their own forms of learning that we need to accept.
One defining thing about us is our neurocentric worldview. Technology looks like things with brains. Plants, though, don’t possess irreplaceable organs, and can be alive in states in which we’d be real, real dead. That’s amazing, and should drop us biologically down a peg. Something we have to admit to ourselves is that all our conceived awesomeness (free will) is chemical, just like plants, which can decide stuff just like we can. Not convinced? Get into Pollan’s New Yorker article and be perplexed, then amazed.