How, When, and Why Humans Learn to Recognize and Distinguish Faces

The ability to recognize and distinguish between faces has evolved over centuries and proven to be advantageous for humanity. This is largely due to the fact that within a fraction of a second, one can distinguish a familiar face from that of a stranger. Additionally, processing facial stimuli has been found to be crucial in social and emotional development. Yet, the processes by which we recognize and distinguish faces is not very well understood. However, recent studies have been able to gain an insight on how humans are able to distinguish and recognize faces as well as when this begins to occur in development.

The discussion by Dr. Greg Reynolds provided valuable insight as to when in development humans gain the ability to distinguish between faces. His work has been done primarily on infants whose age ranged from about four months to nine months. Dr. Reynolds found that within an individual’s first few months of life, they have already developed a preference for more human like faces and developed a strong liking for what is familiar to them. This is evident by the fact that when an infant is about four months old, the infant has already developed a preference for their mother’s face, and they can distinguish between the face of a stranger. Furthermore, since the mother acts as a caregiver to the infant, infants quickly learn to categorize between the faces of men and women and develop a preference for female faces. Additionally, by about nine months infants learn how to categorize the faces of different races and gain a preference for faces of their own race due to familiarity with these faces. Therefore, the work of Dr. Greg Reynolds makes it abundantly clear that it is within infancy that humans have clearly developed the ability to develop preferences for faces while also learning recognize and distinguish between faces familiar to them and new to them.

An article published on the New York Times called, “You Look Familiar. Now Scientists Know Why.” explains the mechanisms involved with recognizing and distinguishing various faces. When an image of a face is presented to an individual, specific neurons will depolarize in response to the retina capturing the image. The researchers at CalTech coined these neurons as face cells. Face cells are located within the brain in patches. There are six patches on both sides of the brain located on the cortex. Experimenters discovered that monkeys process faces very similar to humans, and monkeys have their face cells oriented the same way humans do.  Therefore, monkeys were utilized in the study. In the study, the monkeys were exposed to 2000 pictures of humans. Based on the results of this experiment, the experimenters learned that about 200 face cells are needed to be able to recognize a face. Additionally, when the monkeys saw various faces and features, they were able to distinguish features that deviated from an average. These notable deviations from average are referred to as dimensions, and it was found that about 50 dimensions are also needed to identify a face. Early on, scientists reasoned that face distinguishing was done by just simply assigning various face cells to faces.  However, the process of face recognition is a little more complex than just this. Before information reaches a face cell, it must travel through a few other neurons so that complex information about the shape, size, and features of the face are learned (dimensions). Then once the information reaches face cells, specific face cells will respond based on these dimensions.

While much more work needs to be done to fully understand when and how we learn to distinguish faces, the work of Dr. Greg Reynolds and the CalTech researchers has provided a strong foundation for how these processes occur. As technology improves and more research is done, neuroscientists will hopefully be able fully understand the various processes associated with facial recognition.

Souces:

D., Greg, and Kelly C. Roth. “The Development of Attentional Biases for Faces in Infancy: A Developmental Systems Perspective.” Frontiers, Frontiers, 9 Feb. 2018, www.frontiersin.org/articles/10.3389/fpsyg.2018.00222/full.

Wade, Nicholas. “You Look Familiar. Now Scientists Know Why.” The New York Times, The New York Times, 1 June 2017, www.nytimes.com/2017/06/01/science/facial-recognition-brain-neurons.html?searchResultPosition=20.