Please buckle your seatbelts—I want to cover a good bit of ground rapidly. The impetus for this journey comes from two reports of recent research about (1) facial recognition and (2) differences in facial processing between autistic toddlers and ones developing normally. For more context (that is my plea every time I seek out news but alas it is rare) remember these facets of our humanity that I have posted about in the past. First, one of the earliest advances of our mammalian brains came with the evolutionary appearance of the hippocampus, that started remembering locations, then experiences and then social objects, e.g., conspecifics (see post 5/27/16 and others about hippocampus). Second, remember that the right-sided processing focuses more on the immediate concrete context while the left focuses more on information displaced in time and space primarily through language. This suggests that we perceive something happening now with a more right-sided bias and then process verbal associations about that perception with a left bias. Third and associated with #2, facial recognition of people met in the past, even including family and friends, happens on the right side. A specific lesion there can lead to prosopagnosia, the inability to recognize familiars even though the systems for processing faces is intact, e.g., the person knows it is a face, can often read its emotions, etc.; the person with prosopagnosia just does not recognize people he or she knows. This can happen as a result of brain injury, e.g., stroke, or sometimes occurs developmentally. Fourth, faces are important. Eric Kandel in his very interesting book (see all too brief post 8/27/14) The Age of Insight says that “face perception has evolved to occupy more space in the brain than any other figural representation”. More from him later. Finally, consider the place of faces in human relationships beginning with the attachment and bonding (see post 1/24/14) between infant and parent and on into every relationship afterward. Whew! But wait, there’s more.
Our brains can recognize faces from many angles and even with a face partially hidden; our brains know a face as an invariant form. Our brains then also process a face’s variance, those features expressing current emotion even of those people we have never met though perhaps without the same accuracy as those we know intimately. Some people are able to process micro-emotions. These are expressions that flit across a face that are all but imperceptible to most of us; perceiving these accurately is a fairly rare talent. However, most of us apprehend the major emotions as a person’s facial expression manifests them. Kandel cites research by Paul Ekman that indicates that the upper half of the face, primarily the eyes, features more prominently in expressing sadness and fear, while the lower face, primarily the mouth, conveys happiness, anger, or disgust. And if you want to know if a person’s smile is genuine, you look back at the eyes (a real smile is accompanied by eye crinkling in a particular way).
The faces we find most attractive are more symmetrical; most of us have faces that have significant differences between right and left halves. For example, most of us find the right side is more emotionally expressive. (Remember that the right side of the face is controlled by the right side of the brain; the crossover [decussation] happens lower down the spinal cord that is responsible for right hand-left brain control). For purposes of sexual selection most of us find faces that are symmetrical or at least an ideal face comprised of average features right and left more beautiful (related to my recent post 6/19/17). Similarly most people find faces of people more closely related to them in race and ethnicity more attractive than those less so. So faces again are a big deal.
Science News of 7/6/17 gives a short report of scientists who diligently studied how monkey brains process facial information. The NYT gave a slightly longer version a few weeks back here: https://www.nytimes.com/2017/06/01/science/facial-recognition-brain-neurons.html. Using a variety of techniques, including monitoring the electrical firing of individual neurons, these assiduous folks teased apart how the monkey brain sees faces. They understood this so well that they could assemble how the face looked by examining the brain’s firing pattern. This is remarkable work, I think, because it enabled them to be able to ‘read’ what the monkey was seeing by analyzing brain functioning quite accurately. Look at the NYT piece for the pictures demonstrating this; it is impressive. This science shows how our perceptual system gathers sensory data and assembles it analytically to perform the basic functions of identifying that the eyes are seeing a face, that invariant form, as a precursor to remembering or recognizing that face as familiar.
The next study shows the variability among people in how we examine and process facial information. This was recently reported in the NYT: https://www.nytimes.com/2017/07/12/health/autism-faces-genes-brain-development.html. These results showed a significant difference in how toddlers with and without autism deal with faces. The experimental set-up involved showing toddlers a video and tracking their eye movement. Normal developing children looked at faces more than objects, autistic children more at objects, this to a significant degree. The scientists found that identical twins looked at faces the same way, looking at the eyes and shifting their gaze to take in the whole picture at the same rate. Fraternal twins matched some but not as much. Randomly paired children matched very little. The article also cites research showing that we all have our characteristic ways of looking at faces, some at the eyes and upper half of the face and some at the lower. We tend to go for the eyes to establish recognition, I think. Anyway this study shows a deep genetic influence in how we perceive faces. That, like most mental functions, is complicated, as we construct our percepts using foveal vision (the focused point of view) to gather the details and peripheral vision to help assemble the whole gestalt of the figure (Thank you, Dr. Kandel, for explaining that).
This study is important because faces are so important to our social-mental development. Consider what I call Empathy Central (EC) that the academics call Theory of Mind (ToM), the locus of which is in the right posterior hemisphere and surely feeds off the process of both facial recognition and reading emotional expressions, i.e., empathy. When facial processing is diminished, the development of EC would also be affected. And some differences in the development of facial processing would lead to different personality styles. Remember that reading facial expression connects to the mirroring system via the arcuate fasciculus (or if no recall, see my most read post on the arcuate fasciculus and mirroring from 4/24/14, still read each week by several folks from all over the world), and mirroring (see 9/27/15 post) is also important. Indeed, some of the more effective therapies for autistic spectrum use imitation to stimulate mirroring. By the bye, I read a report in developing this blog that people who are attractive, i.e., have symmetric or the idealized average face (both sides the same) tend to be extroverted, a trait that happens to be quite stable over the life span. Extroverts tend to relax through social contact like, I guess, looking at other faces (or listening to voices over the phone), while introverts tend to relax through quiet withdrawal. You can see how pervasive the place of faces plays in our minds.
Onward from personality and cognitive style to cultural manifestations. Consider that different cultures tend to enhance or diminish facial expressiveness from exuberant to poker faced. Consider the role of faces in art, a subject much discussed in Dr. Kandel’s book, The Age of Insight, where he discusses the stew of ideas in early 20th century Vienna and how these affected painting and how we understand art. (Reviewing this book to help with this post I concluded that I must re-read it in the near future). Dr. Kandel won the Nobel in 2000 for his research in how neurons help us remember. He co-authored one of the first big books on neuroscience I read back in the day, Principles of Neuroscience (1981), and his 2012 book Age of Insight on art, the brain, and the unconscious is very special.
Finally, consider how female faces are treated differenetly in cultures around the world in, for example, our magazines (oh so attractive sells the most) and quite stringently in Islam, where some version of the burka covers the body and especially the face, excepting the eyes sometimes, whenever the woman is in public. Faces go from the sexualized advertising in our media to the binding of personal expression in social interaction, and that is quite a range of manipulating the roles ascribed to females through their faces. Males, not so much. Another aspect of this is from an article I read a long time ago entitled “Perfidious Female Faces” that reported that female faces sometimes conveyed confusing signals when they are angry, i.e., the mouth smiles as other features signal anger, another example of cultural shaping. Anyway, a varied culture of faces, so now we can travel on.