Plants have Intelligence and here is my proof

The overarching aim of this post:

To get us out of a human-centred approach to thinking about intelligence and consider the possibility that intelligence, at least, is available in different forms.

My Way to Hook You

Let’s not beat around the bush here and get straight to the point: do you think plants are intelligent? Any regular-thinking human being will probably respond to this question with an obvious “no”. I mean, what are plants, really? Green and brown structures that take in carbon dioxide and release oxygen (which also happens to be a fundamental life source for humans) and they are able to convert light into energy and nutrients. Some plants thrive in shady areas and some in deserts. They also adapt to their environment, and those who are able to adapt best are the ones who thrive — typical natural selection at play. But what if we were to entertain the possibility that plants do more than just said functions? What if…WHAT IF scientists have demonstrated that some plant processes resemble human function? Would your sense of human-ness feel threatened? Would you feel less special….?

On Human Intelligence

Of course, when I ask you the question on whether you think plants are intelligent, you’re going to say no because the measuring stick you’re using to define intelligence is probably human-centered. You’re thinking about intelligence according to characteristics which are traditionally associated with humans. What are some of these characteristics? Let’s go through some possibilities:

Human Intelligence can be described as…..:

  • Ability to adapt to changing circumstances
  • Including external environments as well as sensorimotor adjustments for goal-directed behaviour
  • Speaking of goal-directed behaviour: ability to create, set, and aim towards goals which also includes things like planning and memory usage
  • Let’s throw in the capacity to forward think/strategize
  • What about self-awareness?
  • And let’s not forget being able to form abstract thought
  • Oh! And communication! That’s important

I think I would be safe in assuming that you probably agree with all or if not, then most of this list. Let’s consult some literature and smarter people. Carroll came out with some thoughts on what he believes intelligence is based on comparing students who fell into certain IQ test score ranges. He divided the types of intelligence in four sub-sections:

(1) Physiological Intelligence, (2) Representative Intelligence, (3) Sensory Motor Intelligence, and (4) Conceptual Intelligence. Let’s take a look at physiological and sensory motor intelligence a little more closely since, well, it’ll be easier for me. He defines the two as follows:

“Physiological processes, as well as other forms of intelligent activity, are subject to modification by experience. The processes correspond to the food, exercise, and climate usual to the individual, but they quickly adjust themselves to changes in any or all of these respects. Sensory motor intelligence is concerned with directing movements of a part of all of the body in response to external stimulation”(Carroll.,1928).

This is good work done by Carroll. First: he’s acknowledged that there are different intelligent types. Second: he has outlined that these different intelligent types manifests itself in a wide range of behaviours and capabilities. The catch though, is that Carroll is discussing human intelligence. Because really, why would any scholar talk about anything other than humans as intelligent?

Like really…Why?

Because it’s fucking interesting, that’s why.

Plant Neurobiology

Plant neurobiology is a relatively new field that looks at what plants do. The goal of the field is to learn about plants. And let me tell you, a lot of interesting work has come out of this field.

With regard to Carroll’s four intelligent types; let’s draw some comparisons (because this will be fun for me): Both physiological and sensory motor intelligence are based on the idea that intelligence lies in the capability of successfully adapting to changes in the external environment. Successful adaptation would be understood as how someone or something is changing their behaviour to appropriately match to the changing circumstance. Where physiological intelligence is focused on the behaviours which are required for basic survival, sensory motor intelligence focuses on the actual movement required to accompany this survival. So do plants do this? Well obviously yes since the point of this entire article would be null if the answer was no.

Brenner et al (2006) demonstrated that plants exhibit behaviour that is of this very nature. They found that:

“To contend with environmental variability, plants often show considerable plasticity in their development and physiological behaviours. Some of their apparent choices include: when to reproduce and the number of progeny to create, how to mount a defense against attacks and in what tissues or organs, and when and where to transmit chemical signals to the surrounding organism. These decisions must be made within the multicellular confines of the complex biological unit of the plant body, and, thus, require coordinated cell-to- cell signaling, which requires a sophisticated information storage and acquisition system” (Brenner et al., 2006).

Basically, with this one quote, we have checked off:

  • Ability to adapt to changing circumstances
  • Planning and strategic capabilities; WRT: progeny creation, defense attacks, etc
  • Communication abilities such as cell-to-cell signalling
  • Information storage (aka: memory)

And if we go up the initial list we created when we were talking about human intelligence, all that is missing is abstract thought, and self-awareness.

Technically, I don’t think I need to go on with making my point but I’ll continue because this is fun. In other discoveries, specifically the one’s outlined in Brenner’s review, the plants clearly demonstrate a very sophisticated communication network.

“Neurobiology also covers the coordinated behaviour of communities, whether these are communities of organisms or communities of genes. Special gene circuits coordinate the behaviour of inter- and intra-specific bacterial communities — this system has been termed quorum sensing. Therefore, it might be surprising that multicellular organisms such as plants have developed gene circuits that could regulate the behaviour of the community” (Brenner et al., 2006).

Did you read that?! Read it again. What is that telling you? It’s telling you that plants not only communicate with one another, but have the capacity to modulate and regulate the behaviours of other plants within their community. If you don’t think that’s sophisticated, then you need to check yourself.

So what have we learned so far? Well, according to Carroll’s defined components of what intelligence is; plants seem to demonstrate at least two out of the four. Can we deem plants as at least potentially intelligent? Still no?

*Sigh* Okay.

Higher Forms of Intelligence as it relates to Plants

Let’s explore the two other components of intelligence which Carroll mentions: Representative Intelligence which is concerned with imagination and memory; so not so much about movements but more about mental simulations and activities — using past simulations or experiences to guide future direction and Conceptual Intelligence which is the process of thinking, making judgements, developing concepts, reasoning, etc.

Representative Intelligence

Let’s think about what memory and imagination actually is. Memory is the basic storage of information and the units of memory allows the organism to access (retrieve) said information at any given time. Imagination is mental simulation which helps the organism make decisions in the future. This capacity also depends on memory as the ability to imagine is influenced by past events which, of course, requires the ability to access memory (Pezzulo et al.,2014). Of course, to build memory requires one to be able to interact with the environment and to not only learn but also understand how the changes in the environment will ultimately influence/effect one’s well-being. We’ve already seen that plants are able to do this. How? Well they don’t just reproduce all willy nilly, they modulate their progeny levels based on external circumstances. Being able to appropriately asses the external environment obviously insinuates that one is using past information (times when it was better and more beneficial to create more progeny and times where it was better to decrease them). This demonstrates, at least, on a very superficial level (you would have to agree), that plants are using stored information (memory), and are using past information to plan for the future (mental simulation aka imagination)

Conceptual Intelligence

Listen, I’m not trying to get carried away here, as much as I love the idea of plants challenging what the notion of human-centered intelligence; I’m not going to discredit this entire argument by reaching too far — we don’t have any evidence to demonstrate the potential for conceptual intelligence so I’m just not going to go there.

My Conclusion

NOW can we say that plants demonstrate a liiiitle intelligence, at least?

If you still say no, then I suspect your reason for doing so could be:

  • I didn’t convince you well enough
  • Perhaps you feel you need to read more research on this ( I encourage this, there’s tonnes of literature on this topic)
  • You feel like intelligence is and can only be demonstrated by humans thereby taking a human-centered approach

If you relate to any of the above points, then I shall leave you be to your own personal journey.

But for those who have at least felt like perhaps they need to change they way they see intelligence and intelligence behaviour:

The conversation is intriguing because the implication here is that plants are demonstrating behaviours and processes which are found in human AND non-human animals.

If we get philosophical here for a moment, what could this mean with respect to contemplations regarding the mind? Were the functionalists correct in stating that it’s not so much the outer shell that matters — so long as the function of the process remains the same — this is all what really matters. A mouse trap is going to kill the mouse despite it being made out of wood, plastic, or any other kind of material, and therefore, we still refer the object that kills the mouse a mouse trap irrespective of any differences we find. So do we do the same thing for plants? Do we take the functionalist view and open ourselves up to the possibility that intelligence is not a uniquely reserved feature to humans and that other organisms, like plants, have the ability to demonstrate at least intelligent-like behaviour? And what that, do we open the door to looking at ANY non-human being as intelligent? Do and will we start treating them differently?

Of course I would say: well why the hell not?

References:

Carroll, R. P. (1928). What is intelligence? School & Society.

Brenner, E. D., Stahlberg, R., Mancuso, S., Vivanco, J., Baluška, F., & Van Volkenburgh, E. (2006). Plant neurobiology: an integrated view of plant signaling. Trends in plant science, 11(8), 413–419.

Pezzulo, G., van der Meer, M. A., Lansink, C. S., & Pennartz, C. M. (2014). Internally generated sequences in learning and executing goal-directed behavior. Trends in cognitive sciences, 18(12), 647–657.