Intelligence in Nature - Jeremy Narby [33]
Chapter 7
PLANTS AS BRAINS
I had been looking into intelligence in nature for eighteen months when a friend called to draw my attention to a recent article in the journal Nature. It claimed that the investigation of plant intelligence is âbecoming a serious scientific endeavorâ and that scientists are âonly now beginning to expose the remarkable complexity of plant behavior.â These were the words of Anthony Trewavas, a professor of biology at the University of Edinburgh and a fellow of the Royal Society, the oldest scientific society in Great Britain. According to Trewavas, plants have intentions, make decisions, and compute complex aspects of their environment.
I looked into the research cited by Trewavas and found, to my surprise, that scientists were now saying that plants have senses and can detect a wide variety of external variables, such as light, water, temperature, chemicals, vibrations, gravity, and sounds. They can also react to these factors by changing the way they grow. Plants can forage and compete with one another for resources. When attacked by herbivores, some plants signal for help, releasing chemicals that attract their assailantsâ predators. Plants can detect distress signals let off by other plant species and take preventive measures. They can assimilate information and respond on the whole-plant level. And they use cell-to-cell communication based on molecular and electrical signals, some of which are remarkably similar to those used by our own neurons. When a plant is damaged, its cells send one another electrical signals just like our own pain messages.
A good part of this knowledge emerged during the 1990s thanks to the development of molecular genetics, which revealed the signals and receptors used by plant cells when they communicate and learn. Anthony Trewavas helped launch this field of investigation with his research on calcium and plant signaling. I contacted him and requested an interview, explaining my purpose. He accepted, and we set up a date.
I arrived in Edinburgh on a cold, stormy January night. As I walked along the streets, I braced myself against the wind and rain. It was my first trip to Scotland. It felt bleak, and I wondered whether I had come to the right place to find out about plant intelligence. I stayed in a hotel on the outskirts of town.
The next morning, the rain had stopped. I made my way over to the university and arrived well ahead of our planned meeting. I wandered around the corridors of the Institute of Cell and Molecular Biology, a nothing-special building designed in the 1960s, which now seemed run-down. Corridors in science departments tend to look alike from one country to the next, with drab walls covered with posters announcing conferences or explaining research.
I found Anthony Trewavas in his office on the fourth floor. A tall, balding man, he has piercing light-blue eyes and gray eyebrows. He invited me in and showed me a chair where I could sit down. His office was littered with stacks of journals such as Science and Nature. I glanced at the top file on the nearest pile of documents and saw that it was entitled âIntelligence.â
By the time I turned on the tape recorder, Trewavas was already discussing the importance of plant intelligence, saying that scientists have long regarded plants as passive creatures, because they lack obvious movement. âNow to my mind, that assumption is wrong because it requires an equating of movement with intelligence. Movement is an expression of intelligence. It is not intelligence itself. Now, the definitions of intelligence are difficultâ¦â
He spoke fluidly, needing no prompting to continue his line of thought. He said he found