Pareidolia: seeing faces or objects where there are none. Those creepy caricatures that stared at you from your bedroom curtains throughout the night, Captain Jack Sparrow in the passing clouds, that so‐much‐like Abraham Lincoln potato, the Man in the Moon (or a rabbit pounding rice if you're from Japan); all are the effects of pareidolia. Scientists must beware of pareidolia – and of how communicating their interpretations can subconsciously influence or “prime” their colleagues to see the same things. Remember Giovanni Schiaparelli's canals on Mars, later championed by Percival Lowell? Many astronomers saw them, yet they didn't exist. And what about the Faces of Xiaojinggou? Chinese scientists spent much time, effort, and money recording the impressions of these “faces” in the rocks of the Daqing Mountains, impressions they could all see but that were later shown to be the effects of pareidolia on their discoverer, and of priming on the archaeologists who subsequently studied them. Basically, our brains are so good at drawing patterns from random information that finding monsters in the shadows is a cinch. Evolutionary psychologists, however, point out that these interpretational errors could, in fact, be very handy. For example, who ever died running away from the tiger he thought he saw? Better to skedaddle than ignore what might turn out to be a real tiger…right? But if this is true, here's a question: could a plant have harnessed the power of pareidolia to avoid becoming a monkey's lunch?

To a South American fungus gnat (Zygothrica sp), the labellum of Dracula orchids looks like a little mushroom (to us, too, if you look closely). Fungus gnats, being the way they are, like to have sex on mushrooms, lay their eggs on them, maybe even grab a bite, and when they turn up on a Dracula orchid (which may give off an attractive mushroomy smell to get the party started), they probably never realize they are being ensnared in the pollination racket. However, when we look at many Dracula flowers, especially those of D simia, it's no toadstool we immediately see: it's a monkey's face (Figure 1). This floral illusion, which has long been explained by pareidolia, is not true mimicry like the aforementioned mushroom imitation. Unlike fungus gnats, self‐respecting monkeys do not facilitate orchid reproduction by procreating on beds of flowers. So when we see these little visages, it's basically our brains making stuff up – or so the theory goes.

But might there be more to this than meets the eye? New research shows that monkeys experience pareidolia too (Curr Biol 2017; doi.org/10.1016/j.cub.2017.06.075). Rhesus monkeys (Macaca mulatta) have been found to spend more time examining images with pareidolic faces (sliced kiwi fruits with pits like eyes, smiley faces in coffee froth, etc) than images with no such alerting information. And they fix their gaze on the illusory eyes and mouth, just as they do with images of real faces. If the monkeys that live (or once lived) where D simia grows experience pareidolia too, might they, like us, see a little monkey in its flowers? And might those flowers have good reason for causing that deception?

D simia grows epiphytically on trees in the cloud forests of southern Ecuador and northern Peru, at altitudes of 1000–2000 m, which overlaps with the general distribution of several monkey species. By engaging the monkeys’ senses with their little faces, might these flowers confuse their potential assailants and avoid being chosen as food? That would increase the orchid's chances of reproductive success, fungus gnat willing, of course. If pareidolia is advantageous to humans, and presumably monkeys, is it such a far cry that an orchid might have evolved to benefit from this?

“It would be very clever indeed if a plant species had exploited this”, says Jess Taubert (National Institute of Mental Health; Bethesda, MD), who led the above research. “These perceptual errors are rapidly resolved by the primate brain; even if a flower is initially seen as a face, it only takes a few hundred milliseconds to determine what the stimulus really is. That said, face pareidolia can be disturbing. It might be possible that monkeys would avoid eating flowers with illusory facial features, preferring to snack on others that are not looking back at them!”

But are the local monkeys pareidolia‐positive? Are, or were, these flowers ever taken as food by any monkey species? Rather than avoid being eaten, might such showy flowers actually end up signaling themselves as salad bars to monkeys less easily fooled and not so fussy about getting a mouth full of horny gnats? Perhaps the whole question of whether a plant could possess a pareidolic defense mechanism is itself illusory, another product of the imagination. There's so much to answer – but we certainly won't figure any of this out if you don't put that telescope down, start paying attention, and stop looking for that rabbit in the moon!

Adrian Burton