At Epoch Times, Makai Elías Calles discusses recent findings about plants’ complex ability to perceive and react to their environments:

Plants lack neurons, but they still readily communicate, including by relaying danger cues.

When a caterpillar bites a plant, it releases a molecule known as glutamate—the same neurotransmitter used in the human nervous system. Glutamate triggers wound-related signaling throughout the plant. Its release primes undamaged parts for defense against pests.

Plants also transmit external alerts. When the caterpillar begins to chew on a leaf, the plant actively emits chemicals into the air. Neighboring plants catch these volatile compounds and begin preparing their defenses.

“Do Plants Have Consciousness?,” August 7, 2026

When findings were first published in the 1980s, they were opposed, because researchers thought they knew what cognition is and it simply could not include plants. But the findings continued to be replicated in various plant species.

It became clear that plants use entirely different structures from animals for similar cognitive tasks such as response to risk. For example, as Calles notes,

In one experiment, researchers divided a single pea plant’s roots between two pots. One pot had a constant supply of nutrients. The other had periods of higher and lower nutrient availability, although it averaged to the same amount.

Researchers tested whether peas preferred a stable or a less predictable resource by observing how the plant invested in its root growth. When the pot with a constant nutrient supply offered enough for survival, the plants played it safe and directed more root growth toward that dependable source. But when that reliable supply was too low for survival, the plant took a risk and shifted toward the pot with an unpredictable nutrient supply—effectively favoring a risky possibility of obtaining enough resources over the certainty of scarcity.“Have Consciousness?”

There is some evidence for a similar sort of cognition in fungi. It may be true of most living organisms. In 2021, prominent University of Chicago biochemist James Shapiro titled an article in Biochemical and Biophysical Research Communications “All living cells are cognitive”, “Supposedly ‘simple’ prokaryotic organisms also display remarkable capabilities for intercellular signalling and multicellular coordination. These observations indicate that all living cells are cognitive.” The discipline seems to have accepted that as a permissible view.

Why were researchers sure that plants could not have cognition? They may have been thinking in terms of a “hierarchy of evolution.” It’s a familiar concept: the long, slow march from mud to mind meant that only toward the upper tier would we find such developments as cognition. But suppose we adopt a different approach. Suppose we assume that any type of life form that has been around for a while has probably done so in part by solving certain decision-making problems, including some complex ones. But life forms use very different structures for doing so.

But does that mean plants are conscious?

It is quite another matter to claim, as recent books have done, that plants or fungi are conscious. Consciousness means something rather larger than cognitive. Both terms are poorly defined but, in general, cognitive just means the ability to sense and respond to an environment. That may be turn out to be a complex ability, even in a life form that we don’t usually associate with decision-making.

But computers, after all, can be programmed to record facts and make decisions about their environments — including much more complex ones than plants have shown in experiments. But most analysts dismiss the idea that computers should be seen as conscious as a result.

Consciousness means, first and foremost, self-awareness. It is not simply the ability to monitor and respond to our surroundings in specific ways. A thermostat can do that. It is seeing the world from the perspective of a self. Dogs, cats, and horses act s if they are conscious in this way. We sense that we are dealing with selves when we deal with them. They don’t have reason or moral choice but they form relationships, including hierarchies of relationships, with other selves.

A case can be made for the octopus as an outlier self too — which hardly fits tidily into a long, slow march of evolution. But are tent caterpillars conscious? Is there any reason we should suppose they must be? If life consists only of stripping fruit trees, cocooning, mating, and dying, perhaps a sense of self would only be a torment.

Much here is opaque, of course. But not everything. For example, Annaka Harris, author of Conscious: A Brief Guide to the Fundamental Mystery of the Mind (2019), makes the case for plant consciousness at IAI.TV:

The controversies will, of course, continue. For one thing, how did plants come to be programmed to make decisions? Simply repeating “natural selection!” is becoming less convincing all the time.

Consider the types of behavior we usually attribute to conscious life, such as reacting to physical harm or caring for others. Research reveals that plants do both in complex ways — though, of course, we conclude that they do so without feeling pain or love (i.e. without consciousness). But some behaviors of people and plants are so alike that it in fact poses a challenge to our using certain behavior as evidence of conscious experience.

“Consciousness may not require a brain Are plants conscious?,” December 8, 2022

But that isn’t generally how we do think about consciousness, is it? We think that there is something that it is like to be conscious, as Thomas Nagel put it. A self that experiences events.

The controversies will, of course, continue and a question looms: Who programmed the plants? The claim that natural selection can do all that is becoming less plausible all the time.