Pavlovian learning, memory and acoustic perception in plants (M Gagliano)

Plants have at least 20 different senses (including electromagnetism), but do not have a centralised nervous system, thus it was assumed they did not 'learn' things in any individual sense and simply had to make the most of their environment and genetics.

Research by Monica Gagliano has found Pavlovian learning in plants, associating the direction of a fan with a light source.
Pavlovian learning in plants

Other research from Gagliano determined that plants do not just seek out water using their sense of moisture-gradients, but also use the sound of water to determine where to put down roots with the greatest chance of finding water.
(Thus, soundproof water/sewerage pipes would be less likely to break from root-infiltration)
Plant roots use sound to locate water

Finally, the long-term persistence of plant-learning and how it relates to the plant's environment.
Persistence of plant learning

-

The research is somewhat controversial, though I think the experiments were well designed and the research could be as applicable to the home garden as it could be to decentralised learning in AI systems.

--

Notes:
"Appel and Cocroft found that recordings of the munching noises produced by caterpillars caused plants to flood their leaves with chemical defences designed to ward off attackers."
"...the ability of many plants to sample soil for nutrients and toxins via their roots, responding in ways that maximize growth and minimize risk; they do this by analyzing and responding to chemical gradients in a way the human body cannot.
As for sight, there is the well-known phenomenon of phototropism, in which leafy stems grow toward a light source to enhance photosynthesis. Add to this the less familiar ability of roots to detect light that penetrates soil, and then avoid it."

This kind of thing is so interesting to me. There is a book called The Secret Life of Trees that talks about tree communication and cooperation.  Also I read something years ago called the baxter report that talked about an experiment where two plants were in a room and a guy came in and destroyed one of them the other one was hooked up to electromagnetic sensors and had different responses afterward. Basically when that guy came back it had intense reaction vs when other people who didn't destroy the other plant came into the room. It suggested that plants feel fear based on past experience and can recognize individuals.  Seems controversial but it makes sense that ALL life would utilize every opportunity to continue life, that seems to be the point.

I enjoyed The Secret Life of Trees immensely, it combined modern science on forest ecology with the observations of a forester turned conservationist. A very poetic text.

Backster did tests with a lie detector that have not been replicable, had design issues and are now held in disrepute.
He also claimed plants had sentience and emotional capacity - which is hard to imagine a plant possessing without a central nervous system.
I think that the anthropomorphism of plants/animals/objects/landscapes does us much harm - particularly when it comes to our deep attachment to pets and gardens.

I think the decentralised learning system of plant tissues is actually a lot more fascinating without invoking the spectre of sentience and a 'soul' - which can be hard to pin down even in human biology (many neurobiologists believe that human consciousness and free-will are more illusory quirks of our physiology than real paradigms).

I note that "The Swiss Federal Ethics Committee on Non-Human Biotechnology analyzed scientific data on plants, and concluded in 2009 that plants are entitled to a certain amount of 'dignity'" (this has resulted in constraints on some types of plant experiments that the government will fund).

While also, "The Animal Liberation Front argues that there is no evidence that plants can experience pain, and that to the extent they respond to stimuli, it is like a device such as a thermostat responding to sensors."

I have watched a couple of her presentations. Exciting work. Excellent science. The reason her work is sometimes undervalued is that her books have mystical tone and shamanism is a constant theme. So sometimes science minded folks can't seperate the spiritual journey from the scientific value of the work and throw the baby out with the bathwater. At any rate I encourage everyone to read the actual studies and decide for themselves about the methodology before they read her book. At any rate it is clear by her research that plants can learn in many different ways in spite of thier lack of central nervous system.

Quoted from the article

'This finding is particularly intriguing and bolsters the argument that associative learning is an adaptive response that is only utilized during daylight hours (when it is most useful) via an internal circadian clock. Interestingly, the response of the control group in this experiment was affected by the phase of the temperature cycle'


It seems that one of the implications of this experiment is that plants learn/adapt better to their environments if their given environments conducive to growth (metabolic/nutritional and environmental/external)

i've never thought about that before. But it's the same with humans for sure- Look at the difference in learning potential and behavior in kids who were autistic/slow before and after implementation of a diet like GAPS for example.

There is an interesting article by Michael Pollan in The New Yorker - 'Plant Intelligence' on this research... note how 'sensitive plants' (a kind of mimosa?) remembered that being dropped was not dangerous enough to cause them to fold their leaves up.  : )  Google 'plant intelligence pollan new yorker'

Oh, this is an awesome topic. I have not read the linked stuff yet but will be soon. I am excited to learn more about the wonderful world of plants. Love the Secret Life of Trees, and the Secret Life of Plants.

I will start off saying these are feelings based off some science and some just gut feelings and speculations I have made by looking at the world we live in.

I think we still have a lot to learn about plants and how aware or not they really are. I think it is quite egotistical of humans to think only in ways of animals ignoring how long plants have been evolving on earth.

Part of me learning to look past my own bias comes from working with reptiles. They are so very different from mammals that most people have a hard time understanding how intelligent or not some of them are. Snakes for example, sadly are rather dumb and mostly instinct. Lizards however tend to have a bit more intelligence, and the monitor lizards surprisingly I would rate around dog and cat level of intelligence. I mix dog and cat as monitors tend to be a mix of the two personality wise. Independent but still affectionate, some mild training to respond to vocal commands can be achieved but they still tend to be pretty strong willed. But here is the thing, they are not mammals, so they have primary instincts that drive them that mammals don't. The issues of warmth and cold are huge primal drives for reptiles. Warmth and cold also effect their ability to think well. A cold reptile will have trouble thinking of anything but needing warmth, similarly an over hot reptile will only think of cooling off. Just right though and they can concentrate on other things. When they are thinking of other things it might surprise a lot of humans how aware lizards can be of not only themselves but us.

I bring all that up, since even within animals it is very difficult to see past our prejudice for mammals being the smart ones. Often forgetting there are reptiles and birds who display some amazing intelligence. Not human level maybe, but certainly in the pet level and possible low primate level. Just different than we are used to. Haven't met a smart fish, but octopus, cuttlefish, and squid all have some amazing levels of intelligence demonstrated. There are even some spiders who have shown some good problem solving and memories.

I think there could be a gradient of awareness and even possible sentience in plants, like with animals. Some animals don't have much awareness or sentience while others do but brain size and even the central nervous system does seem to fully explain why some are smarter than others. So we can't necessarily judge all plants by the experiments with a few. Especially if the experiments are only with the plants that fit in a lab. Trees and bushes would be the plants I would think are most likely to have sentience or intelligence of some sort. Like animals, where the small ones tend to be the least thinking, so too I would suspect for plants so I look to the large and more complex of the plants. There may not be any sentient plant or there may be some. I would rather default to the position of presumed sentience than not, and find out I was just being silly and anthropomorphizing. Considering the alternative of not believing in sentient plants to only find out later they were, I prefer defaulting to sentient plants are possible until proven otherwise. Now my presumption tends to follow the lines of more complex the plant more likely sentient. Again not saying I have science to back it up, just rather default to that than not.

No matter the outcome, I will always consider plants my friends. Just as I do the ants and dragonflies and other animals I don't consider sentient but still appreciate. The lives they live make my life possible, so they are my friends no matter if they can appreciate my sentiment or not.

OK it is getting late for me, and I should be heading to bed, but I was too interested in the links. I got about 1/2 way through the Pavlovian learning, and wow.

Looking forward to reading more tomorrow. Very interesting stuff. It is awesome to read about this type of work being done, and such dramatic results.

Thank you Jondo for starting this thread. Great info share.

Hopefully not wandering too far off topic, but, Jondo, re: Baxter's experiments, there is a recently noticed problem with scientific research ... the 'decline effect' and 'replication crisis' (see Wiki articles on both).  It seems that trials and experiments, when repeated, often no not produce the trusted results that the originals had, no one knows why.   It is causing concern in the scientific community.  I, personally, have a problem with 'scientists' who have already decided what is possible and what is impossible, before using the scientific process to explore a hypothesis (seems to drift into 'dogma' and undermines science's specialty!)

BTW, another great book on animal intelligence is 'Animal Wise' by Morrell... re: fish, see the chapter on the archer fish.  Frans de Waal has long explored animal emotions... especially in primates.  I, too, find this subject utterly engrossing!