Fear and learning in Los Angeles: our evolved propensity for knowing what could eat us alive

On the surface, kids from Los Angeles and children of the Shuar, a society indigenous to the Amazon region of Ecuador, wouldn’t seem to have […]

On the surface, kids from Los Angeles and children of the Shuar, a society indigenous to the Amazon region of Ecuador, wouldn’t seem to have much in common. When I think of LA kids, I think of children who could more easily identify a Shih Tsu than a kinkajou.

But I’d be wrong.

Little Los Angelos might have nothing to fear from their friendly neighborhood jaguar – he’s pacing back and forth at the zoo, after all – but a new study reveals that they are just as ready to learn and remember which animals can eat them as are the Shuar, who might actually have to worry about becoming something’s lunch. A forthcoming article in Evolution and Human Behavior begins to draw back the curtain on humans’ universal, evolved propensity to learn about dangerous animals.

Evolutionary psychologists – as well as linguists and a host of others – believe that human brains come equipped with hardware that allows them to learn things like grammar, for instance. Learning is of paramount importance for most animals. From the moment of birth, in some cases, animals have to figure out what to attack and what to run from, what to eat and what to avoid, what to mate with and, um…what not to mate with, and so on.

According to the paper’s authors, H. Clark Barrett of The University of California, Los Angeles and The University of Wisconsin’s James Broesch, “learning is clearly one of evolution’s most important solutions to the problem of how to navigate effectively in the world.”

But how to learn what we need to learn is a problem in itself.

Do we kiss frogs until we either take a poison dart to the throat or find a prince – an instance of trial and error learning – or do we take a path that might require less dangerous and/or slimy experimentation?

Natural selection would seem to favor the latter, especially when kissing the wrong frog can end in an early demise. If anything really, natural selection should favor a means of learning that includes features that help us avoid exactly that.

Meet prepared learning. With it, organisms can go out into the world already equipped with learning mechanisms. Mechanisms that are ready to acquire knowledge necessary for surviving and thriving without us having to indulge in so much trial and error. For instance, lab-reared macaques that have never even seen a snake easily learn to fear snakes from other macaques.

This isn’t just a case of fear what that guy over there who looks like me fears. In fact, this readiness to acquire a fear of snakes from a conspecific (a member of the same species) failed to extend to flowers. Why? Dangerous snakes do lurk in macaques’ habitats and likely have done so in the species’ ancestral environments as well. Flowers, well, not so much. They might lurk, but they’re much less likely to cause grievous bodily harm.

Similarly, rats can quickly learn an association between eating a new food and feeling ill. But they aren’t nearly as fast at making the association between bright lights or crazy sounds and nausea. Why so? For similar reasons as macaques acquire snake fears and not flower fears.

Here’s where the “frame problem” comes in. There is a ton information at rats’ paw-tips that they could pay attention to. However 1,995 pounds of that ton of information – including the noises that were blaring right before they they felt ill – is pretty useless knowledge, especially compared to what they ate right before nausea set in. In short, noise hasn’t had a history of causing nausea; food has. Organisms should be focused on the useful knowledge relevant to the problem at hand.

When it comes to learning what to eat, rats will stay away from food that makes them ill, but like macaques they can skip the trial and error in favor of something far safer for the situation: social learning. Rats can smell each other’s breath to glean information about which foods in the environment are safe to eat.

So a monkey doesn’t have to try petting a snake to acquire a fear of them, a rat doesn’t have to try munching on something rancid to acquire a distaste for it…and children, it turns out, don’t have to run screaming from an animal attack to acquire information about what creatures are and aren’t dangerous. All thanks to social learning.

Not getting eaten is kind of a big deal when it comes to evolutionarily important things like surviving at least long enough to reproduce. It would make sense then, if in the domain of social learning, such danger-related information was particularly salient. Children, like rats and macaques, should be able to use social learning to learn what could end their social lives early.

This was what Barrett and Broesch were hoping to find in both Los Angeles and Shuar children: a predisposition for attaining and retaining information related to animal dangerousness.

The team presented a number of children from both areas with 16 photographs of animals – Tasmanian devils, Komodo dragons and the like – that were either safe or dangerous, and carnivorous or herbivorous. In the experimental condition, children were told the name of each animal, its diet and whether it was safe or dangerous. Then the photo-cards were shuffled and the kids were asked to relay the information they’d just received. (In the control condition, children were asked about an animal’s name, diet and dangerousness without having been told the correct answers first. This was in order to rule out the possibility that something other than social learning – like familiarity, for example – could be behind kids’ information retention.) A week later, all the children were asked to again give the name, diet and dangerousness of the animals in the photos.

Overwhelmingly, children learned and remembered information about which animals were dangerous, even a week after the initial, single information session and even as they forgot animals’ names and diets. After training, Shuar children got 88% of dangerous or not questions correct – and 83% a week later – while they only scored 63% and then 53% on carnivore or herbivore questions.

In short, both Los Angelo and Shuar children seem more apt to learn and to retain information about threats. The fact that children from both of these disparate cultures performed rather similarly in this respect underscores the evolved, universal nature of a preferential learning mechanism being in play. (No kidding, I’ll eat light bulbs the next time someone shows me a report of a fatal civet attack on Sunset Boulevard.)

Learning which animals are real threats first hand, via trial and error, would have been a costly way to learn. That knowledge – of whether it can be pet or you should bolt – is important to gain, and it has been throughout our evolution. If this information were stored in the minds of more experienced pals, parents and the like, then that’s a better place to learn it than in the jungle, lip-to-frog, hand-to-civet or even eye-to-eye with a Shih Tsu hungry for flesh.


About Jaimie Krems