Why Is There A Face In My Toast?

In 2004, a piece of toast was sold for $28,000. The toast is supposed to show the face of the Virgin Mary.

Some really believe the toast was miraculous. In fact, every year all sorts of extraordinary appearances are reported: Mother Theresa appearing on a bun, Jesus appearing on the back of a bedroom door, and even on the back of a horseshoe crab shell. What's the explanation for these supposedly miraculous manifestations?

All these supposedly miraculous appearances are examples of a more general phenomena called pareidolia. This is where the mind perceives a pattern in vague, often randomly produced, shapes and sounds. That we're particularly prone to see faces and other people in the output of mere chance has been known for centuries. Philosopher David Hume (1711-1776) notes: 'There is a universal tendency among mankind to conceive all beings like themselves... We find human faces in the moon, armies in the clouds.'

Perhaps the best-known example of pareidolia involves the planet Mars. In 2001, NASA's Viking Orbiter 1 spacecraft (pictured) was circling Mars, taking photographs of the surface. As it passed over the Cydonia region, it took a photograph of what appeared to be an enormous, reptilian-looking face 800 feet high and nearly two miles long.

NASA revealed the image, saying it was 'huge rock formation ... which resembles a human head ... formed by shadows giving the illusion of eyes, nose and mouth.' However, others thought this 'Face on Mars' was evidence that there had been some sort of civilisation on Mars. They thought they could discern other artificial structures nearby, including pyramids, and concluded that this was the site of an Ancient Martian civilisation. The truth, however, was later revealed by photographs taken by other spacecraft which revealed the 'face' was just a hill that happened to look face-like when lit from a certain angle.

The Mars Face - as well as faces seen in fruit, cliffs, the embers of a fire, clouds, where, in truth, no faces really exists - are a result of two things.

First, some of the random patterns thrown up in our environment will, by chance, look like faces. That's to be expected. Others will look like dogs, horses, or Jesus. Stare up at the clouds on a breezy day and you can watch a whole menagerie float by. Second, it seems we're particularly prone to see faces in randomly produced visual noise. One scientific study concluded: 'Our findings suggest that human face processing has a strong top-down component whereby sensory input with even the slightest suggestion of a face can result in the interpretation of a face.'

As a result of these two factors combining, we humans can easily faces where there are none: including in that famous piece of toast.

There are also auditory versions of pareidolia. Some believe that in the white noise produced by a detuned radio it's possible to hear the voices of the dead talking to us. Such 'electronic voice phenomena', which feature in various horror films, are another product of our natural tendency to 'detect' humans and other agents (dogs, aliens, ghosts, fairies, or gods) where in truth there are none. This tendency is amplified by the power of suggestion: tell people there's a message to be heard in some random noise, or a record played backwards, there's a good chance they'll 'hear' it.

So, what explains this tendency to over-detect faces and voices? One explanation, offered by Carl Sagan in his book Demon Haunted World, is that the tendency is a product of our evolutionary heritage. A baby that can recognise its parents' faces is more likely to win their hearts and prosper than a child that can't. Humans who can easily detect a human or animal face in the bushes are more likely to avoid or survive being attacked by a rival or eaten by a predator. We have evolved to over-detect faces because missing a face where there is one is likely to reduce our chances of surviving and reproducing, while 'seeing' a face where there isn't one is unlikely to be so costly.Whether or not the above explanation is correct, there's no doubt we are highly prone to see faces and hear voices where in truth there are none. That piece of toast is just one example of this peculiar tendency.

This is a pre-publication draft of a chapter of my book What Am I Doing With My Life?