Humans, like other mammals, live life in the fast lane. Our brains are adapted to notice and react to things that change quickly: we find things that move and make noise to be endlessly fascinating.
Plants do neither of these things, so to us they seem boring, unintelligent, hardly even alive. Cavemen, it turns out, didn’t bother to draw them.
But scientists are beginning to suspect that plants may have their own kind of intelligence. Three lines of evidence point to this conclusion.
First, it is reasonable to expect that all living things are intelligent. Intelligence is expensive, biologically speaking, but stupidity isn’t adaptive. Stupid organisms don’t tend to survive. Any species that hasn’t gone extinct, therefore, is probably at least a little intelligent.
Second, plants have biological mechanisms that allow for intelligence. In humans, intelligence is driven by two main processes in the brain: electrical impulses, and the activities of a group of chemicals called neurotransmitters. Plants have both of these processes – and not only that, but they have many of the same neurotransmitters that humans do.
Third, plants behave as though they’re intelligent. It seems strange to say that plants behave at all, because our fast-paced mammal brains can rarely detect them doing much of anything. Some clever scientists, however, have figured out ways to observe plants’ behavior. In one such experiment, plants reacted defensively to the surprising experience of falling, then learned not to react when repeated falls didn’t actually cause them any harm.
Plant intelligence would have to be very different from human intelligence, because plants face a very different set of challenges in life. However, increasing evidence suggests that plants are aware of what’s happening around them, and are able to react in ways that mirror what a human would do in a similar situation.