Gambling is not a uniquely human quality

Alan Martin July 4, 2016

Gambling is, on the surface of things, a very human hobby to engage in. For one thing, we’re the only creatures living on Earth that have developed currency and thus disposable income to fritter away on who will score next, or how many corners there will be in a match.

Gambling is not a uniquely human quality

Last week we confirmed, again, that this isn’t exactly the case, if you allow the definition of gambling to encompass a broader concept than just money. It turns out that when their survival depends on it, even plants will risk everything on a bet that could very easily go wrong.

Doubling down on survival

Obviously you can’t take a plant down to Ladbrokes and test this on the Grand National, so here’s how the researchers arrived at their conclusions. Pea plants were raised in a greenhouse with their roots split between two pots. By varying the level of nutrients in each pot, the researchers found that the roots would grow more in the pot with the higher nutritional value, as you’d imagine.

“It turns out that when their survival depends on it, even plants will risk everything on a bet that could very easily go wrong”

The researchers then mixed things up a bit. While keeping one of the pots constant and varying the level of nutrients in the other, they found something surprising. In good times, where one pot offered a steady high level of nutrients against one with variable levels, the plants would grow longer roots in the consistent pot, but in hard times the results flipped. If the “steady” pot provided low enough sustenance that the plant’s life was in danger, the strategy would flip, and the plant would double down on the variable pot as a last-gasp grasp for survival. pea_plants_gamble_on_survival

“To our knowledge, this is the first demonstration of an adaptive response to risk in an organism without a nervous system,” said co-author Professor Alex Kacelnik from the department of zoology at the University of Oxford.

“We do not yet know how the plants’ sense variance functions, or even if their physiology is specifically adapted to respond to risk, but the 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.”

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So pea plants can gamble, but what about other organisms? Yep. There’s a body of evidence that suggests other organisms will take similar risks when it comes to self-preservation, from honey bees drinking from a tube that will offer loads of nectar or nothing at all, to dark-eyed juncos which, when cold, will ignore seed dispensers that offer consistency for another that will give them all or nothing.

But what about organisms that just like to gamble even when not in danger? For that, we turn to bonobos and chimpanzees and an interesting discovery from Duke University last year. In short, like humans, chimpanzees will gamble on food if they think they’re going to win, but won’t if they think they’ll lose out.

Optimistic apes

Researchers offered chimpanzees two pieces of fruit or a handful of nuts, with a 50% chance of only getting one piece of fruit if they picked the former. They then repeated the experiment by offering the hungry chimps one piece of fruit with a 50% chance of getting two pieces. On average, the chimps tended to pick the single piece of fruit more often than the two pieces, despite the fact that on average they’d end up with one piece of fruit either way. They just preferred a pleasant surprise to disappointment, it seems.

“At the other end of the spectrum, pigeons have been shown to have more in common with problem gamblers”

“Historically, researchers thought these kinds of biases must be a product of human culture, or the way we’re socialised, or our experience with financial markets. But the fact that chimps and bonobos, our closest living primate relatives, exhibit the same biases suggests they’re deeply rooted in our biology,” Christopher Krupenye from Duke University told Science Blog at the time.

At the other end of the spectrum, pigeons have been shown to have more in common with problem gamblers when set up with a simple slot machine doling out food pellets. Despite the odds being stacked against them, pigeons chose to keep pecking at the button that promised a bigger payday, despite the fact that another button offered regular smaller rewards that added up to more in the long run.

In humans, we now recognise gambling as sharing many of the properties of drug addiction: the feel-good neurological hit gets weaker, and the risks taken to get it grow stronger, often ruining lives in the process. It’s reassuring to take a look at nature and see that, in its purest form, the mechanism is there for a reason. As long as we know when to walk away from the table…

Images: Pelican, Jun Seita and bosketto used under Creative Commons