May
28
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Seeing Faces?
With the plethora of time spent confined to my home during the quarantine, I have found my attention easily drifting. One minute I’m working on my laptop, the next thing I know I’m looking at the wall. At first my mind seems to be meditatively blank, but then I see a creature lurking before me. It stares forward with what I can only assume is its mangled face. While looking at it I can make out every feature, every piece of it coming to life. However, when I try to describe it, the features seem to blur away. My eyes have been fixed in awe of this seemingly massive creature. I instinctively jet my eyes over to see what its gaze is fixed upon. As my eyes travel over, suddenly I am transported directly in front of this face, a poor soul in the path of destruction and most likely in for a wicked devouring. The subtle eyes and blank expression seem so odd, showing no fear in regard to the creature so near. As this thought occurs I simultaneously spring my eyes back to where I assumed the creature was. It has vanished!
In this moment I resign myself back to reality with focused eyes looking at the textured wall I had been entranced by just seconds before.
It may seem that I am spinning a fantastic tale of fiction or drifting off into some form of psychosis; however, I am instead just letting my imagination take flight with the illusory images my brain finds on its own. This phenomenon of seeing faces and shapes in inanimate objects or ambiguous patterns is called Pareidolia, which is explained as illusory sensory perception and is common among most people. A simpler example of this is seeing a face in the bark of a tree or the shape of the letter “A” in the clouds, as it can occur in just about any medium in which your brain can pick up on patterns.
Pareidolia possesses a subcategory called face pareidolia, which as one would likely guess is the seeing of faces in these mediums such as a textured wall.
The recognition of faces in ambiguous patterns or inanimate objects has at times been attributed to a consequence of the viewing of cartoons and the constant anthropomorphizing used in their creation. However, a recent study by Taubert et al. (2017) utilizing rhesus monkeys shows that face pareidolia is not unique to human experience.
The rhesus monkeys underwent an eye tracking experiment in which they were shown monkey faces, illusory faces and a controlled match of the inanimate object. The outcome was that the monkeys look at the illusory faces in the same manner as they do photographs of faces.
Moving back to humans scientists have recently begun to study which parts of the brain might be responsible for pareidolia and face pareidolia. As it turns out the fusiform face area (FFA) appears to be involved. The FFA is a part of the visual system that responds strongly to face stimuli. This is a part of the fusiform gyrus, within the ventral occipitotemporal cortex (VOT), which is implicated in the broader processing of visual information.
Typically, this region is thought to be involved in bottom-up processing from the primary visual cortex rather than top-down processing. Bottom-up processing is when perception starts with external sensory input, theorized by E.J Gibson as “what you see is what you get.”. Top-down processing, theorized by Richard Gregory, utilizes context and our ability to recognize patterns to then infer some part of sensory stimulus that may not actually be there.
A recent scientific article has shown a strong connection between the right FFA (rFFA) and face pareidolia specifically. In this study the greater the activation of the rFFA, the stronger the perception of face pareidolia. This connection points toward top-down processing of information. In top-down processing, pattern recognition is used in terms of context to make an inference. The authors of this article explained this as a match between an internal face template, what we assume faces look like, and sensory input, what we actually see.
In addition to localizing the brain activity important for pareidolia, the authors began teasing out the connections between neurons at work during the experience of pareidolia. The network of activity takes place between the prefrontal cortex (PFC) and the VOT. These regions connect to both types of processing, with bottom-up processing being tied to input of the VOT and top-down processing coming from the PFC. The PFC is associated with the central executive function as selecting relevant information and ignoring irrelevant information.
Now that the neural correlates and network are starting to be exposed, I have found myself curious about the individual differences of pareidolia experience. A very recent study by Keogh et al. (2020) focused on individual difference in regard to mental imagery. The study homed in on activity within the PFC and the visual cortex, both of which are activated in pareidolia. Individuals with a visual cortex that is generally less active but a PFC that is more active tend to have stronger mental imagery. The visual cortex is the initial hub for visual processing, but it is the PFC involved in working memory which holds information in the absence of input. The stronger mental imagery associated with the PFC can perhaps connect to its ability to retain information as the ‘mind’s eye.’ As this research continues, it can potentially provide an avenue in which individual differences in pareidolia can be sought out as well as the unveiling of top-down or bottom-up processing therein.
References
Taubert et al., Face Pareidolia in the Rhesus Monkey, Current Biology (2017), http://dx.doi.org/10.1016/ j.cub.2017.06.075
Liu, J., Li, J., Feng, L., Li, L., Tian, J., & Lee, K. (2014, January 31). Seeing Jesus in toast: Neural and behavioral correlates of face pareidolia, https://doi.org/10.1016/j.cortex.2014.01.013
Keogh, R., Bergmann, J., & Pearson, J. (2020, May 05). Cortical excitability controls the strength of mental imagery, eLife 2020;9:e50232 DOI: 10.7554/eLife.50232
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