Commonly known as the shy plant or touch-me-not plant, Mimosa pudica has delicate, frond-like leaves that fold inward when touched or shaken. They also close at night and reopen with the rising of the sun—a type of movement called nyctinasty.
In a humid tent inside a windowless room in W&M's Integrated Science Center, Vishton and Bartosh exposed these plants to cycles of light and dark and observed a curious change in their movement. "In the first phase of our experiment, we used a 24-hour cycle. On days one and two, the plants were exposed to 12 hours of darkness and 12 hours of light. On day three, the lights remained off," Vishton explained.
After around five repetitions of this cycle, the plants demonstrated increased movement in the "pre-dawn" hours on days when light could be anticipated, but not on the third day of total darkness. "This seems to suggest that the plants were able to 'learn," for lack of a better word, this three-day cycle and shift their movement in response," said Vishton.
Modeling this shift yielded a logarithmic curve, meaning the plants' movement changed rapidly at first before gradually stabilizing into a consistent pattern. "This is the same pattern we see all the time in animal learning," said Vishton. "For example, if you are teaching a rat to perform a series of actions in a certain order, you would expect to see a period of time when they're figuring out the sequence and then a gradual increase in their ability to predict the pattern."
...
"Every theory I've ever read on memory and decision making always involves neurons," said Vishton. "Big surprise, plants don't have those. And yet it looks like they can perform cognitive-like functions. Just not cognitively, per se."
If plants can encode complex functions like enumeration, maybe other non-neuronal tissues can too. "There are lots of cells in animals and humans that aren't neurons. And we just assume they're not involved in learning," said Vishton. "But maybe they could be. Maybe learning is present in every cell. We've just never really studied it before."
How exactly this non-neuronal intelligence is learned, stored and called upon is a question for future experiments.
...
"Typically, we don't conceptualize plants as thinking, behaving creatures, right? We think of them as reflexive objects that are responding to stimuli in a simple way," said Vishton. "But, at least to me, our results suggest that there might not be this boundary between the animal and the plant kingdom—or it might be a lot more porous than we think."
Food for thought: Intelligence is a pretty poorly defined concept when it comes to the scientific investigation of it, even when we're focusing on just human intelligence - not even getting into...
Food for thought: Intelligence is a pretty poorly defined concept when it comes to the scientific investigation of it, even when we're focusing on just human intelligence - not even getting into other animals! We have a bias towards what intelligent behavior should look like due to our human-centric views. I think this also biases us towards thinking about intelligence as something arising purely from neurons. While the evidence pretty clearly supports that our cognitive capabilities are largely dependent on the complexity of our nervous system, it can raise blinders on how we think about the interaction between biology and behavior.
And, for humans anyway, on the environment and its demands. See Cognitive Development by Alexander Luria (and the work of his mentor Lev Vygotsky). I would be willing to bet that plant decisions...
And, for humans anyway, on the environment and its demands. See Cognitive Development by Alexander Luria (and the work of his mentor Lev Vygotsky). I would be willing to bet that plant decisions are similarly affected by environment, especially during development.
Interestingly, the neural theory of cognition/intelligence is starting to give way to a more whole-organism understanding of cognition. See Looking for Spinoza by Antonio Damasio on embodied emotional processing. And a growing literature on glial cells performing information processing rather than just the traditionally acknowledged "support cell" role.
Thank you so much for posting this! My whole career has been in neuropsychology. We might need to change that to neurogliopsychology, or corpopsychology, or....
I've read Lev Vygotsky - I found his sociocultural and zone of proximal development theories informative to my pedagogy! I'll be sure to check out Luria and Damasio as well, thanks for the...
I've read Lev Vygotsky - I found his sociocultural and zone of proximal development theories informative to my pedagogy! I'll be sure to check out Luria and Damasio as well, thanks for the recommendations.
I wholeheartedly agree about looking beyond just neurons. I've joked with other neuroscientists that we tend to look at things only from the neck up, and even then at only just neurons when we're looking at the brain. But neurons are only a small proportion of the cells in your body, and only half of the cells in your brain!
I recently thought about the topic of plants counting because there was a video on reddit the other day of a black widow spider getting trapped by a Venus flytrap. It kept walking at the edge of...
I recently thought about the topic of plants counting because there was a video on reddit the other day of a black widow spider getting trapped by a Venus flytrap. It kept walking at the edge of the trap but it took a while before the trap was sprung. As far as I can tell, the detection of prey seems to require counting and a timer.
When an insect lands or crawls on the trap, it is likely to run into one of six, short, stiff hairs on the trap's inner surfaces. These are called trigger hairs, and they serve as a primitive motion detector for the plant. If two of these tiny hairs are brushed in close succession, or one hair is touched twice, the leaves close down upon the offending insect within half a second.
I understand that it's possible that it is neither counting or timing, but it looks like both are happening from the outside. This makes me think about when I first learned programming. There are a lot of techniques to do things that can be implemented in simple ways that aren't similar to how a thinking being would do them. For example, pseudo-random numbers.
...
...
Food for thought: Intelligence is a pretty poorly defined concept when it comes to the scientific investigation of it, even when we're focusing on just human intelligence - not even getting into other animals! We have a bias towards what intelligent behavior should look like due to our human-centric views. I think this also biases us towards thinking about intelligence as something arising purely from neurons. While the evidence pretty clearly supports that our cognitive capabilities are largely dependent on the complexity of our nervous system, it can raise blinders on how we think about the interaction between biology and behavior.
And, for humans anyway, on the environment and its demands. See Cognitive Development by Alexander Luria (and the work of his mentor Lev Vygotsky). I would be willing to bet that plant decisions are similarly affected by environment, especially during development.
Interestingly, the neural theory of cognition/intelligence is starting to give way to a more whole-organism understanding of cognition. See Looking for Spinoza by Antonio Damasio on embodied emotional processing. And a growing literature on glial cells performing information processing rather than just the traditionally acknowledged "support cell" role.
Thank you so much for posting this! My whole career has been in neuropsychology. We might need to change that to neurogliopsychology, or corpopsychology, or....
I've read Lev Vygotsky - I found his sociocultural and zone of proximal development theories informative to my pedagogy! I'll be sure to check out Luria and Damasio as well, thanks for the recommendations.
I wholeheartedly agree about looking beyond just neurons. I've joked with other neuroscientists that we tend to look at things only from the neck up, and even then at only just neurons when we're looking at the brain. But neurons are only a small proportion of the cells in your body, and only half of the cells in your brain!
I recently thought about the topic of plants counting because there was a video on reddit the other day of a black widow spider getting trapped by a Venus flytrap. It kept walking at the edge of the trap but it took a while before the trap was sprung. As far as I can tell, the detection of prey seems to require counting and a timer.
How Venus Flytraps Work - How Stuff Works
I understand that it's possible that it is neither counting or timing, but it looks like both are happening from the outside. This makes me think about when I first learned programming. There are a lot of techniques to do things that can be implemented in simple ways that aren't similar to how a thinking being would do them. For example, pseudo-random numbers.