Do Plants Think?

A relatively recent (2021) article on plant intelligence, which includes an interview with Monica Gagliano, a professor in Evolutionary Ecology at Southern Cross University in Australia:

Plant Intelligence

It's known that plants can communicate with each other to "warn" their neighbors about potential attacks. Some plants also use animals to defend against pests, such as by releasing chemicals to attract wasps that prey on caterpillars. Researchers have discovered evidence that plants may have "memory" of a sort. In the interview, Gagliano defines intelligence as decision-making in reaction to one's environment. She insists that "you do not need a nervous system or a brain to embody this kind of behaviour and decisions." She goes so far as to declare, "Of course plants are intelligent, as much as bacteria and amoebas, and fish and birds and humans."

Bacteria? That wide-ranging application of the concept may come as a shock to many people's mental categories, as it does to mine. We typically think of intelligence as requiring brains and involving sapience or at least consciousness. I'm reminded of a vintage horror story that begins with a conversation about the nature of mind, in which one character rhetorically asks, "With what does a plant think, in the absence of a brain?" The other character scoffs, while the first maintains that intelligence exists everywhere in many shapes. When or if we eventually travel to extrasolar planets, we might plausibly discover plants or a vegetative group mind possessing a capacity for thought we'd recognize as similar to our own. However, mutual communication might be hard because organisms the size of trees or larger might think on a slower time scale than we do—like Tolkien's Ents, only much more so.

Another article on plant intelligence I came across queried whether, if plants can think in some sense, we would be obligated to stop eating them. If so, we'd be stuck with rather narrow diets, composed entirely of foods we could harvest without killing any complex organism (dairy products, unfertilized eggs, fruits, nuts, honey, the leaves of green vegetables that regenerate throughout the growing season—that's about it). Fortunately, the writer of that essay reassured us we wouldn't, since animals regularly consume plants as part of the cycle of life. Besides, many plants have parts (e.g., fruit) especially meant to be eaten by animals for the purpose of spreading seeds.

Remember the Shmoos in the old "Li'l Abner" comic strip, delicious animals that rejoiced in sacrificing themselves as food?

Shmoo

Maybe on a world shared by intelligent plants and humanoids, some vegetative life forms would partake in a symbiotic partnership whereby they produced renewable offshoots to feed sapient animals in exchange for helpful services such as fertilizing and pest control.

Margaret L. Carter

Carter's Crypt