The Intelligence of Plants Research Paper Example

Throughout history, people have viewed humanity as the dominant species and the plants and animals around us on this planet as nothing more than unthinking, unfeeling things, however, we now know that this is no longer an accurate worldview. Many are aware of very intelligent animals- chimpanzees, dolphins, and crows to mention a few. But what about intelligent plants? The subject of plant intelligence is a highly controversial one. On one hand, some dismiss it as nothing more than pseudoscience, on the other, some believe not only in plant intelligence, but also plant sentience, consciousness, and feeling. In 1973, a book called The Secret Life of Plants was published which changed the way a lot of people viewed plants. It made a great number of very far-fetched claims including plants being both sentient and able to read minds. Whilst the experiments described in the book were poorly designed and executed, the book sparked interest and further research into the subject of plant intelligence. This essay will describe several ways in which plants can be viewed as intelligent, such as their ability to learn new information, remember information, and communicate.

The first obstacle in the path of determining whether plants have intelligence is the definition of intelligence itself. This is no easy task and has been debated throughout history. Some view it as the ability to learn, problem-solve, communicate and remember information- others require consciousness and deliberate thinking for an organism to be classed as intelligent. However, the word “intelligent” in itself is very contentious. Intelligence is a construct created by humans to justify our feeling of superiority to other beings, and so it is ideally suited to humanity and plays to our strengths. For this reason, it is imperative to use a broad definition of intelligence when dealing with organisms that are not humans, and in particular organisms without a brain. 

A first key component of this broad definition of intelligence is communication. Many agree that communication is a highly important factor of intelligence as communication has been vital in the evolution of our species. But what a great deal of people are not aware of is that plants can communicate too. People generally view trees and other plants as solitary beings, but in reality, forests are vastly interconnected below ground by fungal networks. These fungi were once thought to be harmful to plants, however scientists are now aware that this is a symbiotic relationship- the fungi benefit from sugars produced by photosynthesis and in return, the trees receive nutrients that the fungi have obtained from the soil. These networks are technically known as mycorrhizal networks and they transport not only water and nutrients but also information to other trees in the forest. Trees can send distress signals, such as the threat of insect attack, which allows other trees to prepare for the attack. They can also tell when they are sending resources to their species, and even their close relatives, such as “siblings” or “children”, often favouring them over others. This surely indicates a form of empathy and altruism, key components in intelligence. 

The ability to learn information is another key factor in whether an organism is intelligent. A fascinating experiment conducted by Monica Gagliano proved that plants are capable of associative learning - the same kind of learning as in Pavlov’s famous study involving dogs. In this experiment, airflow from a fan was used as a cue that light, a reward, was about to be provided. After 3 days of the fan being switched on before light was provided, around 65% of pea plants grew towards the fan in the absence of light. This is contrary to the expected behaviour of growing towards where they last sensed the light, which would seem to have been the safest option but over just 3 days, they had associated and learned that airflow predicted light. This is incredible, as before this experiment it would have been outrageous to suggest the idea of plants being able to learn, but it seems clear that plants are capable of this crucial element of intelligence.

Memory is highly important in the intelligence of an organism as without it organisms cannot continue to act upon things that they have learned without having to relearn it afresh each time. Memory can be a complex concept, especially when it comes to organisms without brains, so to understand whether plants have memory, one must first understand what memory is. In plants, memory can be defined as the ability to store information and then retrieve that information after some time. If this is what memory is, then plants definitely have it. Not only that, it is thought that they have multiple forms of memory including short term memory, immune memory, and transgenerational memory. Plants being capable of forming, storing and retrieving memories was demonstrated in a fascinating experiment by Monica Gagliano. For this experiment, a Mimosa Pudica plant was used. This plant is more commonly known as the sensitive plant as it curls up its leaves in response to being touched or dropped. In the experiment, each plant was dropped about 6 inches 60 times in a row at 5-second intervals. To start, this caused the plant to curl up its leaves defensively, however towards the end of the experiment, they no longer closed their leaves as they realised and remembered that the drop was not going to harm them. Furthermore, when this experiment was repeated about a month later, the plants did not close their leaves at all-they had remembered that this would not be harmful. This ability to retain information for over a month is much greater than the length of time most insects can remember information, highlighting the importance of examining the boundaries of intelligence between plants and animals.

To conclude, intelligence is a human construct by which we judge ourselves and all other creatures in comparison to ourselves, therefore it will come as no surprise that no other organism has ever, or likely will ever surpass us in this respect. Despite this, plants do possess a form of intelligence. They may not be capable of the same degree of intelligence as humans but they are able to learn, apply, remember and communicate information. Where once we believed humanity to be unquestionably superior to all animals, we have since had to accept that animals can do a vast range of things that we once considered to be uniquely human. Now we must re-examine our relationship with plants and acknowledge that they are far more complex than we have ever given them credit.