Scientist says French beans may be conscious
Could plants be sentient – a basic form of consciousness? A stunning breakthrough at Spain’s minimal intelligence lab suggests that beans may have goals and purposes, just like humans.
Who is the hero of Jack and the Beanstalk? Surely it is the boy who buys the magic beans, climbs the stalk, steals the treasure and kills the giant. But what if the real hero is the bean, growing from a tiny seed into an enormous ladder, reaching into the sky?
That is the exciting implication of new research into climbing French beans which suggests that they may have “goals, gusto and determination” – and qualify for at least the minimum level of intelligence to claim consciousness.
Spanish biologist Paco Calvo used time-lapse photography to find out whether plants grab hold of poles by accident, or by “anticipatory, goal-directed, flexible behaviour.”
The research found their growth was more controlled and predictable when there was a pole to aim for, suggesting the bean plant has a sense of purpose. Calvo argues this is evidence of plant consciousness.
This is a controversial idea. The conventional scientific view is that sentience requires nerve cells that receive information from the external world and send messages to the body. In order to have consciousness – and therefore form goals – these nerve cells need to converge in a central nervous system.
Plants don’t have nerve cells or a brain. So while Jack controls his destiny by choosing to climb, the beanstalk obeys the instructions hardwired in its genes.
But critics call this “plant blindness” – in other words a type of prejudice based on biased thinking that can’t accept the intelligence of plants. This error goes all the way back to Aristotle, who divided the natural world into “inactive” plants and “active” animals.
Time-lapse photography seems to reveal the very busy life of plants. Leaves chase the sun, vines strive to reach a branch, sunflowers work together to share nutrients, and trees fight endless battles against predators.
Some call this approach anthropomorphism: an illusion created by our own narrative-obsessed brains. Historically it has been exploited by science fiction writers. A famous example is the terrifying, human-devouring giant triffid plant invented by John Wyndham in his 1951 novel The Day Of The Triffids.
But Calvo believes we should “rethink our perspectives on consciousness” and widen our definition. For example, sentient life learns to adapt to new situations. “Plants remember,” says behavioural ecologist Monica Gagliano, “They know exactly what’s going on.”
For example the plant known as Mimosa pudica folds up its leaves when threatened, but in a laboratory it can learn not to do so when dropped.
For some biologists this epigenetic memory is evidence of consciousness. Others remain unconvinced. Biologist Rick Karban says it only demonstrates intelligence if we redefine its meaning.
So, are plants conscious?
Seeds of doubt
Some say, no. Plants are complex organisms capable of sophisticated interactions with their environment. But it is too big a leap to claim that beanstalks and sunflowers are conscious. Our desire to see purpose and intelligent behaviour in plants says more about the way humans think than it does about the minds of plants.
Others say, it’s certainly possible. We used to believe humans were unique and the pinnacle of evolution. But the more we explore nature, the more we realise ours is only one way of experiencing the world. Conscious plants may sound absurd, but it is only by challenging assumptions that we can make scientific discoveries.
- Do plants have feelings?
- If plants are conscious, should we treat them differently?
- Draw your own super-intelligent plant and show how it interacts with the world.
- Write a description of the human species from the plant’s perspective. Do plants think humans are conscious?
Some People Say...
“The plant is blind but it knows enough to keep pushing upwards towards the light, and it will continue to do this in the face of endless discouragements.”George Orwell (1903 - 1950), English writer
What do you think?
Q & A
- What do we know?
- It is generally agreed that plants use a combination of electrical signals and chemicals to perceive and interact with their environment. We know that they can detect light, moisture and the direction of gravity to orientate their growth and movement. But they can also “hear” sounds, releasing defensive chemicals in response to the vibration of munching caterpillars. And many trees use an underground fungal network to communicate with each other.
- What do we not know?
- One area of debate is around whether we can really ever understand non-human consciousness. “If a lion could talk, we would not understand him,” wrote the philosopher Ludwig Wittgenstein. Another species experiences the world in a way we cannot begin to imagine. Some find this position too defeatist. Evidence of animal sentience and emotions has helped implement laws against animal cruelty. Just because we cannot achieve a full understanding, does not mean we shouldn’t try.
- Time-lapse photography
- This technique was first used in 1872 to discover whether the hooves of race horses are ever simultaneously in the air. It has since been used extensively to observe movements that are too slow or too fast for the human eye.
- Plant consciousness
- The field is sometimes referred to as plant neurobiology. Plants do not have neurons, but they do have sophisticated signalling networks that could perform some of the functions of a central nervous system.
- The ability to perceive or feel things is considered the most basic level of consciousness, common to the vast majority of animal life.
- The Greek philosopher visualised the natural world as a “natural ladder” (scala naturae) with humans and animals at the top and plants and minerals at the bottom.
- Research at the University of Alberta in 2019 showed sunflowers share soil nutrients by sending fewer roots into fertile soil when planted together.
- Attributing human emotions to non-humans is common in all cultures, but is criticised in biology as lacking objectivity.
- Narrative-obsessed brains
- In a classic 1944 psychology experiment, people watched a movie featuring moving shapes. Without prompting, viewers instinctively told a story about the intentions of the shapes.
- Mimosa pudica
- Pudica is latin for shy or bashful. It is native to South America and is also known as the touch-me-not, the sensitive or sleepy plant.
- Epigenetic memory
- This kind of information is encoded at a cellular level and is passed on when cells divide, allowing a plant to “remember” an environmental stimulus long after it has gone.