INTELLIGENCE BEYOND BRAINS

FLORA FERN

By Abar Hasanat

I recently stumbled upon a 2013 New Yorker piece titled "The Intelligent Plant"₁ that brought a disputed book back into the general view. "The Secret Life of Plants." a 1973 book by Peter Tompkins and Christopher Bird, investigates and asserts the presence of plant intelligence. I was fascinated, but it was evident that many people still dismiss the concept entirely. So I decided to look into if plant intelligence can be established, or whether this study is truly a pseudoscience with untrustworthy results.

The piece sparked a firestorm in the plant sciences world, forever altering how people and scholars saw and researched the realm of flora. It reintroduced to the world this concept that plants, far from being the trivial creatures we always assumed they were, might demonstrate sophisticated intelligent activity. "The Intelligent Plant" is a fascinating insight into the concept of plant intelligence, proposing that despite a lack of a brain, plants are skilled at hitherto unheard-of levels of intelligent activity. This was deemed a controversial take, downright absurd at the time. The plant biology community quickly declared that the assertion was entirely false.₂

Let's fast forward to 2022. Plant biologists and neurobiologists have already created and published hundreds of academic papers, dozens of publications, and hours of video detailing the numerous dimensions of plant intelligence. The following behavioral features have now been documented and may be attributed to plants as a result of extensive observation and experiments:

• Communication

• Learning

• Memory₃

Wood Wide Web or the plant communication network:₄,₅

One significant area of study that has lately gained a lot of attention is the hypothesis that plants may communicate with one another and transmit knowledge and insights across species. An increasing amount of data implies that plants, particularly trees, may interact with one another. This communication occurs via underground Mycorrhizal networks, cobweb-like channels of mycelial growth that form around tree root systems. Scientists believe that these Mycorrhizal networks, termed the "Wood Wide Web," can be utilized for everything from nutrient distribution to communicating the presence of a possible hazard, like a caterpillar.

These Mycorrhizal networks are essentially building an internet-like network system amongst trees, and have the potential to connect an entire forest.

It makes evolutionary relevance for plants to develop communication techniques. Plants are sedentary and do not have the option of fleeing when predators approach. They also lack the ability to distribute their seeds or pollinate the region in which they live. Communication would be an extremely important adaption to help them overcome their mobility limits.

So now coming to the question, can plants learn or be taught classical conditioning?₆

To find out, a Western Australian University research team devised an experiment to assess pea plants' capacity to respond positively to stimulation and performance measures. They began by teaching the plants to link a fan's wind (stimulus) with light (reward). Every day, the team would switch on the fan at the same time as the lights. This caused the plants to associate the fan's wind with the arrival of nourishment.

Researchers were completely capable of teaching the plants to move towards the fan without switching on the lights after only four days. This implies that when the plants felt the wind, they were attracted to the fan even when the lights were turned off. The stimulus was sufficient to elicit a reaction, much as Pavlov was capable of teaching his dogs to salivate in response to the ringing of a bell without supplying food - thereby finding classical conditioning.

The experiment's purpose was to establish if plants could learn via experience, which appeared improbable at the time. Finally, the researchers succeeded not just in their experiment, but also in demonstrating that plants can learn.

Do plants remember or have memories?₇,₈,₉

As study and experimentation into the processes of plant memory persist, one cannot help but wonder, "How can anything without even a brain have memories?" Now that studies have shown that plants can learn and develop memories, the next logical step is to answer the "plant brain" question.

So how do we know plants can produce memories, much alone recall things in general? Research released in 2014 addressed this exact subject. It was discovered that plants may build memories and demonstrate their memory recall through trained responses. Even better, they learned rapidly - in as little as one day.

Despite its lack of a neural system, the mimosa pudica, or "hypersensitive plant," began demonstrating learned responses in just one day. To comprehend the experiment, you must first get acquainted with the mimosa pudica plant and its distinct "reflex," which causes its leaves to fold into the stem. This response helps it hide from grazing animals.

The mimosa plant was dropped 60 times at five-second increments using a custom-built elevator-like apparatus, resulting in the plant's distinctive folding response. The plant ceased folding its leaves after plummeting 60 times. It seemed as though it knew the drop wouldn't hurt it. The study was comprised of 56 distinct mimosa plants, the majority of which displayed a learnt response to halt curling. In short, the plant remembered the fall and its result. It realized it didn't have to curl or fold its leaves in response to the motion.

So, are plants intelligent?

Now that we know plants have their own advanced communication medium, and can learn and have a memory - the main question that arises is whether they are intelligent or not. Well, there’s no absolute answer to this question since it is still a rather debatable topic. While one side is convinced that plants are in fact intelligent, some scholars are still skeptical, and others are adamant that plants aren’t intelligent. Moreover, questions like “Which characteristics are absolutely required to determine intelligence?”, “Are memory, learning capability, and communication methods enough to determine a plant’s intelligence or things like consciousness and decision making should be taken into consideration?”₁₀,₁₁ are being raised which we have no definite answer to. 

However, as more study is conducted, it appears that plant intelligence is a very real possibility. As of today, there is sufficient evidence to warrant more examination, implying that additional research is on the way. So, are plants intelligent? With the information and proof we currently possess, there’s no certain way of answering this. But, one thing is certain that the line between human beings and plants might be a little softer than we previously could’ve imagined!

Works Cited

1. Pollan, Michael. “The Intelligent Plant.” The New Yorker. The New Yorker, December 16, 2013. https://www.newyorker.com/magazine/2013/12/23/the-intelligent-plant.

2. The Week Staff. “No, Plants Don't Have Feelings.” The Week. The Week, January 8, 2015. https://theweek.com/articles/442356/no-plants-dont-have-feelings.

3. Calvo, Paco, Monica Gagliano, Gustavo M Souza, and Anthony Trewavas. “Plants Are Intelligent, Here's How.” OUP Academic. Oxford University Press, October 20, 2019. https://academic.oup.com/aob/article/125/1/11/5575979#191388332.

4. Macfarlane, Robert. “The Secrets of the Wood Wide Web.” The New Yorker. The New Yorker, August 7, 2016. https://www.newyorker.com/tech/annals-of-technology/the-secrets-of-the-wood-wide-web.

5. “The Secret Life of Plants: How They Memorise, Communicate, Problem Solve and Socialise.” The Guardian. Guardian News and Media, April 5, 2020. https://www.theguardian.com/environment/2020/apr/05/smarty-plants-are-our-vegetable-cousins-more-intelligent-than-we-realise.

6. Gagliano, M., Vyazovskiy, V., Borbély, A. et al. Learning by Association in Plants. Sci Rep 6, 38427 (2016). https://doi.org/10.1038/srep38427

7. Gagliano, M., Renton, M., Depczynski, M., & Mancuso, S. (2014). Experience teaches plants to learn faster and forget slower in environments where it matters. Oecologia, 175(1), 63-72.

8. Krulwich, Robert. “Can a Plant Remember? This One Seems to-Here's the Evidence.” National Geographic, May 3, 2021. https://www.nationalgeographic.com/science/article/can-a-plant-remember-this-one-seems-to-heres-the-evidence.

9. Morris, Andrea. “A Mind without a Brain: The Science of Plant Intelligence Takes Root.” Forbes. Forbes Magazine, May 11, 2018. https://www.forbes.com/sites/andreamorris/2018/05/09/a-mind-without-a-brain-the-science-of-plant-intelligence-takes-root/?sh=2432870c76dc.

10. Robinson, D. G., Draguhn, A., & Taiz, L. (2020). Plant "intelligence" changes nothing. EMBO reports, 21(5), e50395. https://doi.org/10.15252/embr.202050395

11. Trewavas Anthony. 2017 The foundations of plant intelligence. Interface Focus. 7:2016009820160098. http://doi.org/10.1098/rsfs.2016.0098