The internet is filled with claims about how we form initial assessments of other people within the first ten minutes – or even the first ten seconds – of meeting them. Add the ever-expanding world of apps that allow us to make decisions with just the swipe of a finger, and you may start to wonder how quickly we are even able to process faces in the first place. Chances are it is much faster than you think.
Faces are a complicated collection of visual information. They provide clues about age, race, gender, emotion, and even level of perceived trustworthiness. Throughout human history we have depended on the ability to make rapid and accurate judgements about people who may help you, who may hurt you, and who you shouldn’t trust at all. Much of that assessment relies on the face. As with many of the tasks vital for survival, our brains have developed a highly specialized area specifically for those tasks: in this case that is the Fusiform Face Area (FFA).
The FFA is located in the visual processing part of the brain and is activated whenever we are trying to process face-related information. However, there has been significant scientific debate about whether this powerful visual center in the brain might be used for a variety of tasks. Is it really exclusively for processing faces, or are faces merely what the FFA handles best?
Some researchers have been able to find non-facial visual tasks that activate the FFA, but the tasks are not consistent across all people. For some the FFA may be used while looking at animals or machines, and for others it may even be a board game. While the tasks themselves may differ significantly, there is a common thread between all of them: expertise.
When the researchers asked participants to identify species of birds or models of cars, everyone used the visual center of their brain. But when the participants had significant previous expertise – they were experienced birders or car enthusiasts – they were more likely to also use the FFA while looking at the images. These and other studies have led to questions about whether the visual information has to have a “face-like” quality for the FFA to be activated, even with prior expertise.
In another study researchers created a series of visual tasks based on the very un-face-like stimulus of a chess board. Participants with various levels of chess expertise were shown a series of images of chess boards. Each image contained an arrangement of pieces on the board and was shown for less than a second. Some of the images had the pieces arranged in such a way as might occur during a real chess game and others images had the pieces distributed randomly over the board.
For the chess experts, these images were more likely to activate the FFA than for the less-experienced players. Additionally, this less-than-a-second flash led to a stronger activation for boards with naturally arranged pieces rather than randomly arranged – but only for those with a high level of expertise. Though the FFA was always more strongly activated for faces than chess boards (as one would expect) the FFA of experts played a larger role for the chess related task than for those with less experience.
But as important as the FFA is in providing each of us with facial-recognition expertise, we still rely heavily on other parts of our brains to interpret the information we receive. Enter the amygdala.
Scientists know that the amygdala plays an important role in decision making and emotional response, including the activation of our fear response. For facial processing, these kinds of assessments are particularly important when assessing the potential trustworthiness of a face. Recent research also suggests that the role of the amygdala may be even larger than previously believed.
One set of researchers scanned the brains of participants while they were shown flashes of a face that lasted only 33 milliseconds. While these flashes are faster than the blink of an eye, they are also – importantly – faster than the visual information can enter the conscious processing in the visual center for most people. That means that the flashes of faces resulted in a response from the amygdala, initiating an emotional response, sometimes without even activating the FFA at all.
It is important to note that while the faces that were shown had qualities that could make them appear more or less trustworthy, a longer look shows that they are all neutral faces overall. This rapid assessment may be important for survival, but it may not be the most accurate assessment in the end. While being amazed that our amygdala can act so quickly, we should also be aware that the faster-than-a-blink assessments that may be affecting our later perception may be based on an emotional response rather than actual visual information.
There is still exciting room for additional research that will reveal even more about how the structure and interaction of our brain regions make such rapid work of highly complicated tasks like facial processing. Just remember that both our speed and expertise in facial processing was heavily influenced on survival needs, and that the conscious work that comes later to put all of that visual and emotional information into a meaningful context is just as important.
Freeman JB, Stolier RM, Ingbretsen ZA, and Hehman EA (2014) Amygdala Responsivity to High-Level Social Information from Unseen Faces. The Journal of Neuroscience 34:32 doi:10.1523/JNEUROSCI.5063-13.201
Bilalic M, Langner R, Ulrich R, and Grodd W (2011) Many Faces of Expertise: Fusiform Face Area in Chess Experts and Novices. The Journal of Neuroscience 31:28 doi: 10.1523/JNEUROSCI.5727-10.2011
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Panel of faces: Rossion B, Dricot L, Goebel R and Busigny T (2011) Holistic face categorization in higher order visual areas of the normal and prosopagnosic brain: toward a non-hierarchical view of face perception. Front. Hum. Neurosci. 4:225. doi: 10.3389/fnhum.2010.00225