By Katharine Santiago
We have all heard about people seeing faces in toast, whether the story comes from a friend or a TV show, it is something we are all aware of. But why do some people see faces in things that don’t have faces, and why is the face of Jesus so commonly seen? As it turns out, there is actually a neurological explanation for this phenomenon. It is known as face pareidolia, and it describes the perception of faces in objects without faces. It is a rather common phenomenon, so common that there is an entire twitter page dedicated to it (@facespics).
A few scientists in 2014 decided to research the neural mechanisms behind face pareidolia, specifically focusing on activity in the face fusiform area (FFA), which is responsible for facial recognition. Participants were told to detect both faces and letters from noise-images, and compared the results to participants who were told only to look for non-face images. They looked at the activity in the FFA as well as other regions responsible for letter recognition. By comparing the activated neural networks, the mechanisms behind face pareidolia could be differentiated from the mechanisms behind other forms of pareidolia, for which were previously known.
In the study, there were 5 different stimuli with faces varying in detectability, ranging from images with easy-to-detect faces (image A) to an image that is “pure-noise” (image E).
Image F was used to establish participant’s hemodynamic response, which shows the metabolic activity in the brain, which can tell us what brain activity looks like when a participant is looking at nothing. (Sheth, et al., 2004). The same types of images were used for the letter stimuli.
Participants first went through a training round, where they were shown images with faces and noise, and pure noise, as well as those with letters and noise, and pure noise (images A-E). For the testing period, however, only pure-noise images were used, and it was the same image for both letter detection and face detection. The participants were shown several noise images and told half of them contained faces. After each image, participants indicated whether or not they saw a face. Then, a localized test was done where participants were shown images with a face, object, letter, or random noise in them.
The purpose of the images with letters was to have a comparison between letter pareidolia and face pareidolia, since the mechanisms behind the latter phenomenon were unknown. The results showed that those who showed letter pareidolia were also more likely to show face pareidolia. The researchers also concluded that when participants experienced face pareidolia specifically, there was an increase in activity in the right FFA. This pattern was only seen when participants explicitly said they had seen a face in the pure noise image (Liu et al., 2014).
Understanding face pareidolia provides us with greater understanding of the ways in which our brains work to produce the behaviors that are shared among individuals. Growing our knowledge on these behaviors may help us to one day understand why we experience the world the way we do. So, the next time you think Jesus is appearing to you in toast, or the mailbox looks like it’s smiling, remember it’s all about brain activity, even if the mailbox seems friendly.
Sameer A. Sheth, Masahito Nemoto, Michael Guiou, Melissa Walker, Nader Pouratian, Arthur W. Toga. Linear and Nonlinear Relationships between Neuronal Activity, Oxygen Metabolism, and Hemodynamic Responses. Neuron, Volume 42, Issue 2, 2004, Pages 347-355, ISSN 0896-6273,
Jiangang Liu, Jun Li, Lu Feng, Ling Li, Jie Tian, Kang Lee,
Seeing Jesus in toast: Neural and behavioral correlates of face pareidolia,
Cortex, Volume 53, 2014, Pages 60-77, ISSN 0010-9452,
Faces In Things: https://twitter.com/facespics?lang=en