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The last decade saw the rise of the field of “plant neurobiology (植物神经生物学)”. That debatable field is based on the idea that plants — which do not possess brains — handle information in ways similar to complicated animal nervous systems. This thinking implies that plants could feel happiness or sorrow or pain, make intentional decisions and even possess consciousness. But the chances of that are “effectively zero”. “There’s nothing in the plant comparable to the complexity of the animal brain,” says Taiz, from the University of California, Santa Cruz.

Some plants are capable of complicated behaviors. For example, wounded leaves can send warning signals to other parts of the plant. But plants perform these with equipment that’s very different from the nervous systems of animals, no brain required, Taiz argues. He and colleagues point out methodological faults in some of the studies that claim plants have brain-like command centers and animal-like nerve cells. But beyond the debate over how these studies are conducted, Taiz’s team argues that plant consciousness doesn’t even make sense from an evolutionary point of view.

“Complicated animal brains advanced in part to help a living being catch a meal and avoid becoming one,” Taiz says. “But plants are rooted to the ground and rely on sunlight for energy, an inactive lifestyle that doesn’t require quick thinking or outsmarting a predator (捕食者) — or the energetically expensive nervous systems that enable those behaviors.” “What use would consciousness be to a plant?” Taiz asks. “If a plant worried and suffered when faced with a threat, it would be wasting so much energy that it wouldn’t have any left to do anything about that threat,” Taiz says. “Furthermore, plants have plenty to do without having to be conscious, too. With sunlight, carbon dioxide and water, plants create the compounds that sustain much of the rest of life on Earth,” Taiz points out. “Isn’t that enough?”