a culture of faces

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.

Eric_Kandel_1978

Eric Kandel 1978 Thanks, Dr. Kandel

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.

Dogs, language and laterality

The linguistic lateralization of our dog buddies spotlights a theoretical mystery

Many news outfits have published stories about a recent study wherein dogs were trained to lie still enough in an fMRI while listening to humans talk to them. The results indicated that our evolutionary partners processed emotional tones on the right side of their brains and specific words on the left, just like humans. The more we study dogs, the more we find how smart they are and how much we have adapted to each other for interaction. Check out the research done by Brian Hare and colleagues.

I first read about the fMRI study in Science News from 10/1/16. It provides a good summary (as they usually do—what a good magazine) and then they ended the article with the idea that because dog-human relations have only developed over the last 30,000 years, too short a time for evolutionary progress to produce such linguistic abilities, “some older underlying neural mechanism for processing meaningful sounds is present in other animals”.

This highlights for me the theoretical mystery on the biological nature not just of language but of symbolization in general (so it includes art as well). As I have said before, understanding symbolization is the holy grail of understanding ourselves biologically, and so let me render a conceptual outline of this mystery. First consider the bond between dogs and humans and that emotional communication through voice (and sight) is processed by the right side of the brain in both of us. We have researched this broadly in humans as intonation or non-verbal vocal communication, and/or kinesics. All of this to my mind is empathic communication and its processing is right sided; we find a cortical area for its integration there at the tempo-parietal junction that I call Empathy Central but the academics call ToM (Theory of Mind). Do dogs have an Empathy Central area? Unknown for now but I am taking bets they do and planning on how to spend my winnings.

zackyawn

Looking left, currently bored

Next consider this basic feature of lateralization. The right side processes emotional expression and empathic communication just like it processes the current perceptual-motor domains, i.e., the right side processes the specious present. The left side then directs its energies towards information displaced in time and space, initially as a supplement to the specious present by recognizing and recalling information and then increasingly as a virtual domain for information to be composed independently from current objective events. Language, as a symbolic function, is so powerful because it allows us not only to control the input and retrieval of displaced information from memory, not only because it allows the composition of new information from imaginal processes, but also and especially because it allows us to communicate about what isn’t there in front of us but exists only in our minds, apprehensible only to oneself and in symbolic communication.

So when the article ends by asking what the underlying neural mechanism might be, my answer is not about language but about its precursor in the symbolic control of displaced information. Why should that be lateralized to the left? Ah, because timing is important. The right side matures at a faster pace than the left, due primarily to the differential effect of testosterone which slows the left’s maturation more than the right’s (and so males show more distinct patterns of lateralization and more language problems from sometimes too slow a pace on the left side). The right side develops the capabilities to process current information early on while the left side is coming online, so to speak, a bit later, and when it does come on line, it is not totally in sync with the right sided processes for the specious present. Its information is displaced (read out of sync) almost from the beginning of the incipient specious present. Symbolic processes enable finer, more powerful control of such displaced information. So the right side focuses more on the current coin of interaction, i.e., empathic communication, and the left side more on non-current, i.e., displaced, information. Verbally this relies on lexical knowledge, the processing nexus of which is in the left temporal-parietal junction. As we learn more about animals, especially mammals, we will find the precursors of these underlying neural mechanisms in virtually all of them. You can count on it.

A couple more quick notes. It would seem likely that dogs were domesticated and became our close buddies because the genetic streams feeding their evolution ran close to ours—our brains are sympatico in how they process social information.   Human genetic streams, however, also evolved a lower larynx and hyoid bone, greater breath control, and oral-facial musculature thereby enabling articulate speech and even more critically to our humanity, gave rise to longer cortical fasciculi. The arcuate fasciculus is a prime example here. Remember that it carries the surface structure of words on the left side between front and back so that we can repeat what we just heard said. On the right side it might could carry emotional expressions for mimicking. (See my most popular post from 4/24/14, Arcuate fascicles, mirror neurons, and memes). The important feature here, however, is that these long fasciculi facilitate the composition of invariant information forms, e.g., words, discrete emotional forms, and their expression. (And how about art and its special modes of symbolization? Ah, beautiful). The creation of these invariant forms is what enables the separation of deep and surface structures and the subsequent development of syntactic control of their compositional connection. The creation of these invariant forms, both long-standing (lexical items) and in passing (conversation), by the welter of connectome activity in the presence of ambient flux is the remarkable basis for humanity’s intelligence and it has grown from deep roots.

Finally, remember to mark your calendars for Mammalian Heritage Day on November 2 and celebrate those roots. Travel on.