Plants with Personality


Saguaro National Park near Tucson, Arizona. Photograph by Jorn Napp

by Emily Anthes

If you had to be an endangered animal, you’d be better off as a tiger than a toad. If you were a tiger, filmmakers might cast you in wildlife documentaries and journalists might write heart-rending stories about the disappearance of your kind. Your furry mug might appear on magazine covers and postage stamps. And conservation organizations just might make you their flagship species, a stand-in for all the critters whose survival is threatened. In other words, if you were a tiger, you might have a fighting chance of at least making humans care about your predicament.

That’s a taller order if you’re a toad, an animal that wins over few human hearts. Instead, we prefer the so-called “charismatic megafauna,” funneling our emotional and conservational energies into species like tigers, lions, elephants, dolphins, pandas, and the like.

A number of psychologists and biologists have begun to uncover why some species appeal to us more than others, identifying a number of factors that make certain kinds of critters especially attractive. For instance, we have a soft spot for our fellow mammals, and we  prefer big beasts to smaller ones. We’re also strongly attracted to “neotenic,” or juvenile-looking, features. The youngsters of many species have large heads, large eyes, big foreheads, and snub noses. Human infants have these characteristics, as do puppies, kittens, and all sorts of other critters that we find cute. In some species, adult animals retain features associated with youth–such as oversized eyes–and we’re naturally drawn to these neotenic faces.

Slow Loris. Photograph by Silke Hahn

An animal’s coloring may also, well, color, our perceptions. In 2006, David L. Stokes, a researcher at the University of Washington, Bothell, published a paper on penguins, which look more alike than different, all dressed in their matching black-and-white tuxedos. Stokes found that even a dash of color could win us over; according to his research, we seem to prefer penguin species that have a dash of warm color–red or yellow–on their bodies to those that are entirely black and white.

Our preferences for certain species over others have serious implications for conservation.  Studies have shown that charismatic megafauna attract more than their fair share of conservation attention and funding. As Stokes put it in his 2006 paper: “Much of the world’s biodiversity will survive only if humans choose to protect it. Given that people are likely to protect what is important to them, human preferences will be important determinants of many species’ prospects for survival…”

It never occurred to me that this idea might apply not only to animals but also to plants until I came across the work of Emily Hounslow, currently a PhD student at the UK’s University of Sheffield. For her master’s degree in biology, Hounslow explored the notion of charismatic plants. It’s an interesting notion–and one that hasn’t been explored much. After all, plants in general are much less charismatic than animals, less likely to earn our affection or conservation attention. (In one study, researchers found that elementary and middle school students were twice as interested as learning about animals as they were about plants.)

But within the plant world, some species are surely more attractive to us than others, and Hounslow argues that it’s high time to figure out what makes one woody green thing more appealing than another. In her paper, “What is a charismatic plant?,” Hounslow writes:

The idea of defining and explaining charisma has been investigated a lot in animals. Together with the recognition that charisma affects the flow of funds towards endangered species, this shows that it is important for our understanding of how conservation efforts work in practice. Yet, charisma, and the subsequent biases it creates, has not been explored at all in plants before.

In the paper, Hounslow explores the characteristics that might make certain plants especially appealing and attractive to humans. (The paper appears to be unpublished, but you can download a copy of it here.)

Rafflesia Arnoldii, Lake Maninjau, Sumatra, Indonesia. Photograph by Henrik Hansson

Not surprisingly, she suggests that size might play a role, prompting our interest in towering giants like redwoods. Flower size and brightness may also influence our preferences. Uniqueness may also be important, she suggests; a pine with needles that stand out from those of the other local conifers or a tree with a distinct, easily identifiable shape is likely to catch our eye. Plants that are iconic and characteristic of certain landscapes–consider, for instance, the saguaro cactus–may also be especially appealing to us and garner more than their fair share of attention.

Hounslow draws no definitive conclusions in her paper and acknowledges that rigorous, quantitative analysis is needed to determine what makes plants charismatic. But she suggests several sources of untapped data that researchers could use for such studies. They could compare plants selected to represent conservation projects to those that are not, she says. They could also assess plants featured on magazine covers or on botanical tours. Finally, researchers could study the amount of money raised for the conservation of different types of plants, she suggests.

These types of analyses could be useful in two ways. By revealing what kinds of plants we’re most attracted to, such research could help conservation organizations pick flagship plant species that draw public attention to the plight of threatened plants. At the same time, knowing more about our biases toward certain types of plants could help ensure that, as Hounslow puts it, “these biases can be corrected in order to ensure conservation effort is based on need, not human whims.”

Piece originally published at PLoS Blogs | Creative Commons License