Author: Samantha E Andres
Source: Calvo, Paco, et al. “Plants are intelligent, here’s how.” Annals of Botany 125.1 (2020): 11-28.
What is intelligence?
Organisms interact with the world around them in many and vastly different ways. For many years researchers have debated how intelligence manifests itstelf in different organisms. In recent years there have been many advances in this field with scientists, studying intelligence in birds, octopi, monkeys, even in the microbes that are all around us. And while this research is quickly advancing in the field among the fungal, bacterial, and animal kingdoms, there has been a less widely accepted view of higher intelligence among plants. Since some of the fundamental arguments on this concept have surfaced, there has been a wealth of exploration on this idea across disciplines. In this review paper, the team combined literature and theory from the biological sciences, and psychology, to dive into what exactly determines intelligence and how might we be able to apply this in the context of plants. Using a series of psychological definitions, and adding the word “plant” where the word “agent” would normally be, the team developed three definitions of intellegence.
‘(1). Intelligence is a property that an individual plant has as it interacts with its environment. (2). Intelligence is related to the plant’s ability to succeed or profit with respect to some goal or objective. (3). Intelligence depends on how able the plant is to adapt to different objectives and environments’ (Legg and Hunter, 2007, p. 5)
Photo of a hammer orchid being pollinated b a thynnine wasp. This orchid emits sex pheremones tricking the male wasp into thinking it is a female. Upon discovering the flower the wasp is fully convinced, as the orchid also has developed a floral structure similar to the look of the female wasp. Photo by Esther Beaton
Anthropomorphism, an innate tendency of humans in the way we look at the world
From a human-derived stance, one might look at the concept of intelligence and compare that to ourselves. An important problem when studying intelligence across many organisms is the fact that there is a bias towards animals that are more familiar to us humans. For example, many of us will consider primates and dogs as smart but will not necessarily think of octopus as having intelligence despite the fact that they have a highly complex brain. Similarly, we see fungi when they fruit aboveground, but it was only until recently that we have begun to understand the ways in which they interact with the world around them. For example, what many would consider just a simple slime mold was shown to be able to solve mazes, and it has been observed that fungi can act like a communication network for trees to utilise in which to speak amongst one another.With plants being furthest from us on this evolutionary tree, one might argue that they are of the least intelligent of the kingdoms. Although plants may not have a nervous system, they do use forms of electrical connections to interact and respond to outside stimuli (Calvo et al., 2017). Additionally, plants have hormones that allow different cells and tissue structures to respond to changes in light, herbivory, disease, or fire. While a plant might not have the same type of internal immune response that a human has when it gets sick, they do have mechanisms by which they fend off disease such as the release of antimicrobial chemicals, or creation of barriers within cell walls to stop the spread of disease. And just like we make a hot cup of soup, or take medicine, these responses in plants are simply a modification of behavior to improve survival.
Photo of a corpse flower Amorphophallus titanum taken by the team at MEIJER GARDENS. This flower only blooms once every 18 years. In order to commence pollination, the plant emits an odour of rotting flesh, which is at its most potent at night in order to attract flesh-eating insects at the time in which they are the most active.
Plants also have the capacity to respond to environmental signals, that change often, and abruptly such as water, wind or light. Additionally, some plants have complicated life cycles that interact with the world around them in response to particular environmental stimuli. For example, some plants will delay flowering and fruiting for up to 70 years, putting all of their reproductive efforts into a big season, to improve the probability of success and establishment. Additionally, some plants have the capacity to delay flowering and fruiting until particularly optimal environmental conditions in order to maximize germination success. Plants even have the capacity to “trick” other insects into providing pollination services. Just as the fight or flight syndrome kicks in when faced with a stressful situation, plants have complicated chemical pathways, or evolutionary adaptations that they use to defend against predators.
So the question still remains, is adaptability to new situations a valuable argument for intelligence?
What about changing behavior in order to succeed under changing conditions?
It seems this topic is still up for debate….So what do you think?
Can plants, fungi and other unassuming organism be intelligent? Whether plants are intelligent remains strongly debated in the scientific community. But new discoveries are showing us the remarkable ways in which plants and other organisms interpret and respond to the world around them. Next time you take a stroll through nature for some deep thinking, consider how the organism around you are responding to you.
“Every great advance in science has issued from a new audacity in imagination” -John Dewey
Calvo P, Sahi VP, Trewavas AJ. 2017. Are plants sentient? Plant, Cell & Environment 40: 2858–2869
Legg S, Hunter M. 2007. A collection of definitions of intelligence. In: Goertzel B, Wang P, eds. Advances in artificial general intelligence: concepts, architectures and algorithms. Frontiers in Artificial Intelligence and Applications. Amsterdam: IOS Press, 17–24.