My late cousin was a serious grower of roses with his flowers winning awards at local shows. On a visit to his garden once, I noticed that he had placed a radio in the middle of all the rose bushes and he told me that he had heard that plants thrive on music. I too had heard this but dismissed it as the whimsy of plant lovers. I even teased him by asking him which roses bushes were not performing up to his expectations and when he pointed them out to me, I gave them a stern talking to.
It appears that plant neurobiology, the study of plant cognitive abilities, has become advocated by some scientists but now another group has launched a vehement attack on the whole idea of sentience in plants, saying that the limited response by plants to changes in their environments have been over-interpreted as suggesting a higher level of cognitive development than is warranted.
Bothered by claims that plants have “brain-like command centres” in their root tips, and possess the equivalent of animal nervous systems, the critics counter there is no proof of sentient vegetation or structures within plants that would grant them what the neuroscientist Antonio Damasio has called “the feeling of what happens”.
Writing in the journal Trends in Plant Science, where plant neurobiology made its debut in 2006, Lincoln Taiz, a botanist at the University of California, Santa Cruz, and seven like-minded researchers state: “There is no evidence that plants require, and thus have evolved, energy-expensive mental faculties, such as consciousness, feelings, and intentionality, to survive or to reproduce.”
But the proponents of plant sentience are fighting back, saying that the critics are merely prejudiced and ignoring the evidence.
The broadside drew a robust response from the University of Sydney’s Monica Gagliano, who conducts research on the cognitive abilities of plants, including perception, learning, memory and consciousness. She said the criticisms failed to take account of all the evidence and focused only on work that supported the authors’ viewpoint. “For me, the process of generating knowledge through rigorous science is about understanding the evidence base behind a claim,” she said. “Where is their experimental data? Or are we expected to just accept their claim at face value?”
When one views time-lapse videos of how plants respond to changes in their environments, one undoubtedly gets a feeling that they have a sense of agency. But my own uninformed reaction is to still feel skepticism towards the idea that they have any kind of consciousness as we understand the word in the context of animals, since they do not seem to have a central nervous system.