Plant Consciousness Is Flowery Nonsense
"In claiming that plants have consciousness, ‘plant neurobiologists’ have consistently glossed over the remarkable degree of structural and functional complexity that the brain had to evolve for consciousness to emerge," they write.
The field of "plant neurobiology" cropped up around 2006 in response to the plethora of remarkable discoveries about plant behavior hinting that our (mostly) green friends exhibit smarts beyond what many had thought. Since then, the intriguing findings have continued apace. In 2014, a team found evidence of basic learning in Mimosa plants. The plants' leaves are noted for folding inward when shaken, dropped, or touched, but when subject to repeated, innocuous falls in the experiment, the Mimosas stopped curling inward, as if they knew that the drop wasn't harmful. Two years later, that same research team published evidence that plants could be classically conditioned to follow the breeze of a fan that had been associated with blue light. Then, in 2017, a study seemed to show that venus flytraps could be sedated.
In the new op-ed, scientists led by University of California-Santa Cruz developmental biologist Lincoln Taiz argue that skepticism is warranted for all of those findings – the former two have been difficult to replicate, while the latter "sedation" discovery could be explained by inhibitory effects on cellular and biochemical processes, not a loss of consciousness.
Still, assuming that all of those discoveries are genuine, Taiz and his co-authors do not think they warrant the bold claim that plants are conscious. Plants lack neurons or brains, and are too organizationally simplistic, they say.
"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. Plant development and behavior can be regarded as a series of nonintended consequences emerging from internal and external signaling networks that have evolved through natural selection."
Instead, it appears the drive by some scientists to endow plants with consciousness is more driven by ideology, the authors conclude.
"This new wave of Romantic biology appears to have been inspired by a justifiable concern about humanity’s continuing ecological degradation of the biosphere: the loss of habitats and biodiversity, the over-exploitation of natural resources, and the crisis of climate change...
"While we agree entirely that biodiversity needs to be protected, we strongly object to the implication that plant consciousness, intentionality, and cognition are moral or ethical questions. A scientific understanding of nature requires only that we seek the truth."
Source: Lincoln Taiz,, Daniel Alkon, Andreas Draguhn, Angus Murphy, Michael Blatt, Chris Hawes, Gerhard Thiel,7 and David G. Robinson. Plants Neither Possess nor Require Consciousness. Trends in Plant Science 2019. http://dx.doi.org/10.1016/j.tplants.2019.05.008