Why we recognize strangers and other neurologic mysteries


Have you ever stared at a person without recalling their name or where you know them from? Don’t worry, it happens to everybody. Here are some possible explanations for why you recognize strangers! But first, let’s find out how our brain sees the people around us.

Face recognition is a complex process that involves thousands of neurons named “face cells”. They are divided into a dozen groups symmetrically placed in the temporal lobes. When you look at somebody, the retina receives the image of a face. The face cells process and compare this information with previous facial models. The process of facial recognition includes 50 general features, as the shape of the nose and eyes.

Neurologic explanations

Two Caltech biologists conducted an experiment on macaque monkeys  to better understand the process. It seems the animals could identify a face previously seen using only 200 of these face cells.

The neurological structures vary from person to person. Some people can’t recognize faces, not even their own. This condition is called prosopagnosia, also known as `face blindness`. Their visual perception is intact, yet the `face cells` don’t process the information they receive.

Other people can differentiate even between identical twins. Most of us fall somewhere in this spectrum. Some people may mix up the facial characteristics of two un-related individuals because they have poor face-recognition abilities.

Some scientists believe that two structures localized in the hippocampus cause this phenomenon. These are the dentate gyrus (which makes you believe everything you see is new) and CA3 (which, in opposition, makes everything familiar to you). It turns out that the CA3 structure sometimes misjudges the information and this is why you think you recognize strangers.

A trick of memory

Another idea related to this subject refers to the original learning context and retrieval context in which you meet someone. When you fail to connect these two, embarrassing social situations might occur. For example, I was able to recognize my university colleagues on campus but failed to do so if I saw them on the street. This happened because the environment was different and I hadn’t yet memorized their faces to be able to separate the stimulus from the context. On another occasion, somebody waved at me while I was walking in the park. I recognized them, but I lacked information about our first encounter.

A Mental shortcut

The halo effect could be another explanation. This manifests when people associate one visible trait with another one.
An experiment conducted at Stanford University illustrates it perfectly. The participants saw 40 photos of faces then they had to identify them from a set of 80 pictures. The volunteers recognized photos of attractive faces even if they had not previously seen them.
People associate attractiveness with familiarity. This means we are drawn to people with pleasant appearance and mistake it for familiarity.

Remnants from another life

Yet sometimes people recognize each other even if they have nothing in common. Even if they never met, they quickly develop an unexpected feeling of intimacy. There isn’t yet a clear scientific explanation of this phenomenon but this might mean we have to think outside the box to understand it. According to Randi Gunther, the strong bond between two people is transmitted to their descendants. In other words, we don’t inherit just our ancestors’ genetics, but their friends as well.

These are only some of the ideas regarding this subject . We are yet to discover the intricate mechanisms of our brain and why we recognize strangers. The next time you see somebody vaguely familiar, strike up a conversation to find the context in which you might have previously met. You can always use a new old friend!


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