Book Review: The Light Eaters by Zoë Schlanger
by Robert Graham
I approached The Light Eaters with some degree of skepticism. It is not too often you walk into your local bookstore and find a book about plants on display as a highly recommended New York Times Best Seller. When it came to the subtitle, How the Unseen World of Plant Intelligence Offers a New Understanding of Life on Earth, my skepticism grew further. Plant intelligence has always been a controversial topic in the plant biology community. Detrimental pseudo research like The Secret Life of Plants (1973), and the constant anthropomorphizing of plant behaviors from writers and individuals who aren’t botanical researchers has always shadowed the impressive real science behind plant intelligence that has gone largely unreported.
The conflict over plant intelligence largely lies in what our definition of intelligence is. The Oxford definition of intelligence is “the ability to acquire and apply knowledge and skills.” But for many, intelligence implies cognizance, reasoning, problem solving and emotional intelligence. We don’t even afford this definition to many animals, let alone plants. Schlanger mentions numerous examples of plant interactions resembling intelligence that many disregard due to the lack of cognizance. Research relating to plant chemical signaling in forested ecosystems, including popular recent works like The Hidden Life of Trees by Peter Wohlleben and Finding the Mother Tree by Suzanne Simard,are examples that reference the chemical signaling of forest plants through intertwined mycorrhizal networks and carbon transfer. Schlanger takes examples of work like these as well as others to draw the reader to their own conclusion. Readers are able to see into the thought process of the individual researchers Schlanger interacts with, and are able to take that information and formulate their own opinions without being forced into any specific narrative.
One of the first published works Schlanger describes is in chapter 3. There she explores David Rhodes’ work on forest plant’s communication in response to insect predation. Rhodes’ research in the 80s tells a different story of plant communication that expands further than the intertwined mycorrhizal signaling many are familiar with today. His work is entirely more surprising, and harder to explain. Rhodes’ findings showed trees being predated on by caterpillars were able to signal to plants far outside of the intertwined network. These other individual trees not yet under attack were able to respond by increasing defense compounds in their foliage and preventing further predation when the caterpillars did arrive. This theme was and still is in some sense controversial. Communication, suggested intentionality, and awareness, which in some way can be regarded as a form of intelligence.
Schlanger springs off this topic to beautifully build and explain the history and story of plant intelligence through the eyes of the researchers she interviews. Her writing style really makes you feel as though you have a connection with the stories of the researchers and an understanding of how difficult publishing can be in the peer-reviewed scientific community. This review process is essential for discovery in science, and to make sure research can be trusted and unbiased.
What Schlanger depicts so well in her writing is how difficult this process can be for a topic such as plant intelligence, where the scientific community is largely divided. Success of published research is ultimately the way a scientist receives more funding opportunities to continue on their research. When Schlanger writes about the pressure that published work is under, you can really feel it. Whether you are someone who has participated in a peer-reviewed research project and know the work involved, or if you are simply interested in botanical writing as Schlanger is, you can really relate to the process through the deep dive explored throughout the book.
The Light Eaters is some of the best reporting on the research of plant intelligence there is. It walks you through the history of the research, the controversy, and slowly builds up to the incredible findings being made today in the evolving field—all through the eyes of the researchers who have been working in the field for the last half century. You never feel forced into a narrative to either side of the debate throughout the reading; you’re simply walked through the findings by the scientists who found them. Scientific observation is intentionally just a published discussion of the findings of the data of the research on a given hypothesis. From there, it is up to us to interpret what it means. What we define as intelligence and communication and how do the findings factor into our understanding of those two concepts.
The book will leave you thinking more deeply about plant interactions than you ever have. When you experience nature, it is hard to see it in the same way after reading The Light Eaters. You become inspired by the tip of the iceberg—wondering what is yet to come from the research on our understanding of the natural world and what it means to be a part of it.
Robert Graham is the Land Steward at New England Botanic Garden at Tower Hill in Boylston, Massachusetts. He has been with the organization since 2017 and is responsible for overseeing all formal groundskeeping as well as management of all naturalistic areas including meadows, woodlands, and wetlands. Robert earned his BS in Biology from Worcester State University where he focused on conservation biology and GIS. His professional interests include early successional habitats, native plant ecology, and sustainable land management.
