It’s a point of contention and a hotly debated topic as to whether or not plants feel pain or have a brain capable of consciousness like other living vertebrates.
Researchers in the new field of plant neurobiology argue that plants can indeed think.
But in a new opinion article published in the journal Trends in Plant Science, a team of experts in plant physiology attempt to put the topic of plant consciousness to rest once and for all, arguing that because plants lack neurons and a brain, they are incapable of consciousness.
Instead, plants grow using electrical signals to distribute molecules across the plant’s membranes and send long-distance messages in case of danger like an insect bite.
Plant neurobiologists use these signals to prove the plant’s ability to think, showing that the distribution of signals is similar to the electrical signaling in the nervous system of animals.
In the new article, Lincoln Taiz from the University of California cites research from Todd Feinberg and Jon Mallatt who studied the evolution of consciousness to show why dumbing down consciousness to fit the basic chemical signaling of plants is a problem.
“The biggest danger of anthropomorphizing plants in research is that it undermines the objectivity of the researcher,” said Taiz. “What we’ve seen is that plants and animals evolved very different life strategies. The brain is a very expensive organ, and there’s absolutely no advantage to the plant to have a highly developed nervous system.”
The Feinberg-Mallat model of consciousness determines what must be in place in the brain for a species to have awareness.
It was Feinberg and Mallat who traced back the origins of consciousness to the Cambrian explosion 520 to 560 million years ago, much earlier than previously thought.
“Feinberg and Mallatt concluded that only vertebrates, arthropods, and cephalopods possess the threshold brain structure for consciousness. And if there are animals that don’t have consciousness, then you can be pretty confident that plants, which don’t even have neurons–let alone brains– don’t have it either,” said Taiz.
Taiz and his colleagues say that the chemical signaling in plants are genetically encoded responses that have been fine-tuned through natural selection.
The researchers argue that sensory adaptation doesn’t involve learning and shouldn’t be linked to consciousness.
But Taiz and his co-authors emphasize that these responses are genetically encoded and have been fine-tuned through generations of natural selection.
“I feel a special responsibility to take a public position because I’m a co-author of a plant physiology textbook,” said Taiz. “I know a lot of people in the plant neurobiology community would like to see their field in the textbooks, but so far, there are just too many unanswered questions.”
By Kay Vandette, Earth.com Staff Writer