The animal and plant kingdoms are divided by many distinctions. In terms of recognition and identification, we often acknowledge that we are closer to our fellow mammals, animals – even fish and sea creatures – than we are to the plants, seaweed and trees that surround us.
But Monica Gagliano of the Centre for Evolutionary Biology at the University of Western Australia was on a NewsTalk programme recently, and her research sheds light on the plant’s abilities to think and react to danger or potential rewards in a manner similar to animals.
Cognition of this kind in plants may lead to a shift in the way we view them. A redefinition of intentionality may be in order. Gagliano described cognition as the total suite of mechanisms that encompass the gathering, storing and processing of information, and how it’s used. During the radio interview, she further showed what her research means in redefining plants’ cognitive abilities.
“The mimosa pudica was the first of a series of studies that I did on the possibility of plant learning. It’s the same kind of learning that you think of when your kids go to school and learn something that they didn’t know before. It’s nothing to do with your genetics, it’s got nothing to do with things that you knew before and you were encoded with.”
Her research involved conducting experiments on the plant that it could not have encountered before in its evolutionary history.
“We consider it like basic, simple learning. It’s called habituation. If you are in a room and you start paying attention to every single thing in the room – the fridge going off, and the birds outside, the cars passing, the dogs barking – if you pay attention to everything in that space, you waste a lot of energy because a lot of that is unnecessary to you.
“We wanted to see if the plant could learn to ignore the unnecessary stuff going on around them, and pay attention to the things that are relevant, things that depend on survival and death. The experiment with the mimosa was to see if they could learn to ignore the unimportant stuff going on around them. The plants do learn, and they remember for a long time, relatively speaking.
“I created a set-up where I could do controlled drops of the plants onto a comfy foam platform from about fifteen centimetres.
“Plants don’t move as we understand movement –their movements are either too fast or too slow for our timescale. Mimosa is the sensitive plant – its responses are in our timeframe. It closes its leaves rapidly and it has been known to droop and play dead. It’s a very kid-friendly plant because it reacts and responds so quickly to disturbance.
“When a plant like this closes its leaves, the plant loses its ability to photosynthesise, so it’s a lot of investment in avoiding a predatory threat.
“We had to do a training session, which consisted of sixty consecutive drops. I started dropping my plant. The plant closes its leaves because it doesn’t know what’s happening and it should protect itself. A third time, some of the plants are reopening their leaves mid-flight. And then not bothering to close their leaves at all.”
Her work with garden peas worked like Pavlov’s dog. Pavlov’s dog hears the bell ringing, and each time the bell rings, he gets food. So the dog starts to salivate when the bell rings, predicting its dinner.
Gagliano’s “dinner” for the garden peas was blue light, and the “bell” was a wind fan. She first checked whether the fan was meaningless. The fan alone didn’t affect the movement of the plants. But if the fan blew at the plant from the direction of the light, the plant moved towards the fan expecting the light. Even if the light had previously come from another direction, the plant learned over time to follow the fan. The green pea plants felt the breeze and responded before the arrival of any light, following the direction of the fan while ignoring its original instinct to move towards the previous light source.
The utilisation of animals as a food source has been regarded as ethically problematic for centuries. The treatment of animals and fowl in industrialised farming has become a source of contention in more recent decades. One innovative solution comes in the form of lab-produced, artificial and protein-rich meat, currently in development. Although expensive, mass production will bring down the cost of such products. Veganism has also been touted as another moral solution to cattle-farming and battery farms. But now, perhaps veganism too will become problematic.