Tuesday, 12 July 2016

Brained agents discover gambling peas

"We do not conclude that plants are intelligent in the sense used for humans or other animals, but rather that complex and interesting behaviours can theoretically be predicted as biological adaptations ... [T]he findings lead us to look even at pea plants as dynamic strategists and to model their decision processes just as one would model an intelligent agent."

So says Professor Alex Kacelnik, from the Department of Zoology at Oxford University, elaborating on the results in his co-authored paper in Current Biology. Enter the pea plant as a strategist and in this case one prone to gamble for its longer term benefit.

A zoologist is of course is unlikely to ever think of a plant as intelligent as an animal, even though in recent years philosophers and botanists have strayed into this territory, but a gambling pea has raised the stakes.

This group of researchers from the UK and Israel showed that a pea plant could in effect take a risk on where it produced roots if it somehow assessed that would be on balance a good thing for its survival. Laboratory plants had their roots split between two pots, one with a constant level of nutrients, the other with varying levels. If the nutrient levels in the constant pot were low the plant took a gamble and produced more roots in the second pot. If nutrient levels were constantly high, it didn't bother.

This is how Current Science illustrates it:

And this is pretty much how we respond to risk. The human example they give is the choice between a guaranteed $800 or tossing a coin to receive $1000 for heads and nothing for tails. Mostly you take the reliable $800, but if you needed $900 for a fare to get home from a remote location and to survive a potentially threatening situation, you may as well take your chances. The $800 doesn't help at all while the toss of a coin gives you a fifty fifty chance of getting out of there.

So these pea plants realised - well, were hard wired to conclude - that if the going was no good in one pot they may as well risk sending roots (and using up valuable resources) by exploring territory that may or may not provide a better source of what they needed to survive. The plant was able to assess that this risky option could help them survive longer.

Presumably the pea plant is 'simply' tempted by the higher nutrients on the occasions when the variable pot is in the positive territory but the interesting thing is that this seems to only happen then the stable pot is low in nutrients. So they aren't tempted by more nutrients when things are reliably sufficient in the other pot. That is, if the peas were us they are happy to take the $800 on offer unless they need more than $800 to survive and their sensors tell them there is what we might call greener grass elsewhere worth investing in.

So don't tell Nick Xenophon and his NXT Party (for non-Australians, this is a political party with one of its central - and very reasonable - tenets that we should do all we can to reduce gambling in Australia, including banning its advertising) but plants seem be we willing and able to take a bet. 

The researchers now want to present plants with all kinds of other tasks to test what they call their 'adaptive responses'. Their goal is to find out just how much a plants evolved responses resemble the way 'brained agents', like us, make decisions. The zoologists are unlikely to be ever convinced that plants are intelligent but we know, don't we...

Images: The pea with a face is the icon used for twitter handle @Just_a_pea, the cartoon from Current Biology, and the others are of plants growing outside our back door at home (just don't tell Lynda I've uprooted one to photograph it for this post).


Daisy Debs said...

There's me thinking that roots just follow moisture . There's obviously a lot more to it than I thought ! Very interesting : )

Tim Entwisle said...

Plants do some clever things. I don't know that the peas are going to form government soon, but perhaps a seat or two in the Senate? Tim

Andy Jackson Consultants said...

"Pea Brain" is a fascinating piece of research. It would be interesting to extend this research to wild relatives to see if some species are higher risk takers than others and whether this is linked to the environmental conditions in their native habitats. This research could be very valuable for breeding new crop varieties in marginal areas where the addition of artificial fertilisers is limited.

It reminds me of the research described in Susan Cain's "Quiet" where researchers found introvert and extrovert behaviour in the same fish species. The chances of survival of the species was enhanced by having both behaviours expressed - extroverts left a shrinking pool to join the river whilst introverts stayed around to the bitter end. However, extoverts tended to offer themselves more readily to predators by hanging around in the centre of the pool rather than being "wall flowers". Perhaps there are introvert and extrovert peas out there. I love the fact that we are still discovering profound things about plant biology.

Tim Entwisle said...

It's an intriguing time for plant biology, or even plant neurobiology if you will. We've always know that plants do all kinds of interesting things but at a pace that means we find it hard to notice and 'respect'. As a paid up member of the Australian Skeptics Society I need plenty of convincing for unconvincing things but I like the idea of pushing these boundaries. It's good to question, to probe, to hypothesise... There are plenty of questions here about what the pea is doing when it produces more roots but whatever the interpretation it makes plants even more interesting and, as you say, raises even more questions. I must admit I like the idea of introvert and extrovert peas in my back garden, each doing what they must! Tim