Neuroscientist Greg Gage performed an experiment showing plants can count and “think” during a TED Talk published this month. This is just one piece in a larger puzzle starting to show that plants could have a form of consciousness.
Gage prefaced his experiment by asking, “What has a brain?” He said that, when pushed to define the difference between something that has a brain and something that doesn’t, students will often say, “Things that move tend to have brains.” That is correct, Gage said.
For his experiment, he used two types of plants that move rapidly. A mimosa plant curls up when you touch it. A Venus fly trap closes its “mouth” when a fly gets in there.
Neuroscientist Greg Gage measured the electrical pulses inside plants that are like neurons firing in the brain.
He hooked up electrodes to a mimosa to show that electrical signals fire in the plant when it is touched, sending a message to the stem to move the leaves. This is similar to neurons firing in the human body, facilitating communication between the brain and the parts of the body that need to react to a stimulus.
Gage hooked the electrodes up to the flytrap. Similarly, when he touched sensory hairs inside the flytrap, it created an electrical pulse in the plant. But it didn’t close. That’s because flytraps will only close their mouths if they are sure there’s a fly in there. It takes a lot of energy to open and close the mouth.
How are they sure? By the number of times the sensory hairs are stimulated. That means, Venus flytraps can count.
Venus flytraps can count how many times flies land on them.
Plants don’t have brains, said Gage, but they can communicate using electricity. He connected the two plants together to see if the electrical pulses in one could affect the other. When he touched the hair of the flytrap, the mimosa plant curled up.
In 2015, German forester Peter Wohlleben wrote “The Hidden Life of Trees,” astonishing the world with how trees communicate with each other.
German forester Peter Wohlleben showed in his book “The Hidden Life of Trees” that a forest is a community in which trees communicate, make friends, and protect each other.
When a tree is being nibbled, for example, it can send out a chemical to warn other trees that there’s a hungry creature in the area. The other trees can then release chemicals that make them less appealing.
Trees share nutrients with each other through their root systems. Stronger trees share sugars with weaker trees. The idea is that they are all stronger if they stand together. If individual trees die, they leave open space for wind to come in and batter other trees.
These are just a couple of examples of the amazing ways trees interact. And it doesn’t seem to be just some automatic and arbitrary process.
A tree won’t treat all other trees equally. It chooses its friends.
Two trees who aren’t “friends” will heavily reinforce their branches when they touch, “so you get the impression that there’s quite a shoving match going on up there,” Wohlleben wrote.
“But a pair of true friends is careful right from the outset not to grow overly thick branches in each other’s direction. The trees don’t want to take anything away from each other, and so they develop sturdy branches only at the outer edges of their crowns, that is to say, only in the direction of ‘non-friends.’”
Wohlleben has observed stumps from trees that have long fallen kept alive by the trees around it. A forest won’t keep all its stumps alive, so is it a sense of veneration for an old friend that causes it to sustain certain stumps?
It could have to do with the “degree of connection—or maybe even affection,” Wohlleben wrote.
Other scientists have suggested plants are very ‘mentally’ capable.
The extent to which trees feel or think in the same way other beings do, including ourselves, is unclear. But Wohlleben and Gage add to a body of evidence that has already grown up, controversially, around the topic of plants’ higher sensibilities.
Scientists have shown that plants have long-term memory, they are aware of their physical environment and the behavior of other plants, and even (most controversially) that they may be able to read a person’s thoughts.