Merry Christmas. I am of course most interested in the biological roots here but my indentured servitude with the farm has taught me to look for the flowers and the fruit as well. An example of the former is that from Darwin’s keen and thoughtful observations of emotional expressions in animals, including humans, in 1872, through Ekman’s and his colleagues more modern and beautiful research into the universals of emotional expression, we have come to understand that we, apes and others express some consistent emotions through our facial expressions including joy, anger, fear, disgust, sadness and surprise. We have learned that the right side of a person’s face better expresses their current feelings, and no surprise here, dogs looks at our faces the same way. An example of the fruit is the duality of drama in its comedy and tragedy. Of course as we have modernized in our understanding and art, we have developed many shades of their combination. Interestingly, through a variety of means (Wada test, strokes, surgery, split brain studies, etc.) we have found that the right hemisphere shows a tendency for negative emotions and the left for positive ones. Why? I think the difference inherently lies at least partly in how each hemisphere handles the temporal processing of information. The right dominates in focusing on the current moment, searching for the new to understand the situation and, once we have some experience under our belts, relate it to old data, which, let’s face it, over our life is mostly about difficult times. As we monitor new, relate it to old, and behave in the moment, possibilities, the freedom of movement, recede. On the other hand, the left dominates in focusing on information displaced in time and space, transforming old information from experience into a new imaginative context with many possibilities. And to quote Angelique Kidjo, a most wonderful singer, “Possibility is joy.” Sorrow comes when no other possibility exists. Root, flower and fruit. Happy New Year.
Here is a rendering of the corpus callosum with some of the grey matter stripped away in order to reveal how extensive its fibers are throughout the cerebral hemispheres. The corpus callosum is a large system of nerve fibers connecting the right and left hemispheres. We know something about its functioning through the split-brain operation, slicing it through to contain otherwise intractable seizures and from brain imaging studies. We know that it is larger in females than males, so that the research cited earlier on 12/10/12 showing greater inter-hemispheric connectivity for females and greater intra-hemispheric connectivity for males and which result in sexually stereotypical patterns of social strengths and particular task focus is consistent with neuroanatomical research. It is not mature at birth and so any mutual communication between right and left sides must be done through other, lower structures, mostly through bilateral processes. As it does mature, maybe from 2 1/2 and 4 1/2 years of age, left and right begin to inhibit the other in some functions, freeing the left to process language and other more abstract information and relegating to the right the necessary streaming of current information, e.g., the sensorium, body orientation, social interactions, etc.
Here is the maturational pinnacle. Around age 3 1/2 the hemispheres have separated in function and then, I think, they reconnect in a new way and the child realizes that these words used with people have an immediate meaning of something he or she has created in their own mind. It is a coupling of possibility to the here and now and it is, I believe, the first epiphany of mind.
Brains vary in the degree of being lateralized. Both males and females go from less lateralized (which I will take as indicating the potential for androgeny) to strongly lateralized male and female patterns. While I am focusing on brain differences, these very differences contribute over time to cultural normative behaviors, especially the expression of masculinity/femininity, the expression of emotions and the facilitation/resolution of cooperation, all under the old rubric of manners. Male and female cultural stereotypes are just that and mask still many differences in brain structure and function. So early on in gestation, the fetal brain is essentially female. Both sides of the brain are engaged with the current concrete situation, i.e., the immediate stimuli fields impinging on the sensory organs internal and external. When lateralization begins, brains start to specialize higher level functions, the right to continue its focus on the here and now as the left begins to separate out old from new in a special way where old can stretch very far back and the new include self generated visions, plans and fantasies. As infants become children the process of lateralization extends to the cerebral hemispheres, the highest brain structure (so far?) and we see the emergence from the biological roots of humanity of empathy (right) and symbolization (left). Next up, the corpus callosum and the first pinnacle of our maturation.
A week or so ago earthsky.org, a favorite source for science news, reported on a study using a relatively new technology that mapped neural connectivity in the brains of 949 youth aged 8-22. They found gender differences that appeared in adolescence and were most pronounced in the young adults. Males had greater connectivity within each cerebral hemisphere and females had greater connectivity between the two hemispheres. The investigators interpreted this as supporting other findings which show that males do better at specific tasks depending on spatial and motor skills and females do better at memory and social cognition.
How do such differences arise? That they appear later in development suggests that experience and practice play an important role, but we know that gender differences arise early on in our development. Mammalian (yes, that includes us) fetuses are essentially female and some are masculinized in the course of gestation through the operation of hormones such testosterone. Bird brains are the opposite, they are essentially masculine but are feminized by hormones. Testosterone affects the developmental pace of the two cerebral hemispheres differently,slowing down the maturation of the left relative to the right. Because males produce more testosterone their hemispheres differ more than those of females. Some research shows that the cortical layering needed for accurate processing can be disrupted in the left hemisphere with the result that males are at greater risk for language disorders.
The greater social abilities of females come in part from the greater integration between the right hemisphere, which leads in processing the current moment and empathic communication, and the left, which leads in processing information displaced in time/space, i.e., abstract, and skilled motor actions, i.e., praxis. Males’ greater abilities in spatial abstraction for navigation and sensorimotor speed come in part from their focus on such mental domains set apart from the current social moments.
Jaak Panksepp in his book Affective Neuroscience says that there are really four sexes based on the different sexualization between body and brain. We can have a female body and brain, a male body and brain, and also a female body with a male brain and a male body with a female brain. It would be interesting to know if these differences in connectivity appear similarly in the LGBT populations.
Here is link to the story:
I want to convey and discuss how deeply biological I believe our humanity is and to start off this task, I think a narrative of exemplars from my life’s learning can provide important context. This begins with reading the work of Susanne Langer in college and thereafter; her writings focused on symbolization and art, then moved on to the biology of mind in her three volume magnum opus, Mind: An Essay on Human Feeling. From there I became interested in linguistics, especially psycholinguistics, so that I read Chomsky, the many who carried forth his ideas about grammar, and David McNeil, Lev Vygotsky and many others who extended this focus on child development. This led to my gaining my M.S. in speech and language pathology and developing even further my interest in language and brain. Thus, as I worked with children with language learning disorders, I read more linguistics and began a survey of the great brain scientists of the day, Luria, Pribram, Jackson, and many others, including Norman Geschwind.
I had the good fortune to attend a conference he organized and spoke at during this time. Given the brain science of today, it seems eerie to remember that prior to Dr. Geschwind’s work in the late 60s/early 70s, many if not most neurologists believed that the two cerebral hemispheres were virtually identical. Dr. Geschwind told us that he took a 6 inch rule down to the basement where brains were preserved for study and measured the plenum temporale (one nexus for language processing) in this sample and showed that the hemispheres were indeed quite different. Of course we know today that lateralization differences appear throughout the different levels of the nervous system in humans and other animals.
I took something of a break from language and brain and pursued my Ph.D. in clinical psychology. I had planned on specializing in neuropsychology but both my graduate program and clinical internship lost key faculty and resources in this area and I became interested in the more severe psychopathology evident in children and adolescents. This led to learning more about attachment and trauma and this led me back to understanding brain development and the impact of experience during the sensitive maturational period and later on in adulthood. Another myth fell by the way as I learned that contrary to what I had been taught over two episodes of graduate school, neurons continue to be created well into adulthood.
Finally I have had the pleasure most recently to delve back into aesthetics, the philosophy of mind and brain science with a renewed focus on the biological roots of humanity. This means to me to learn about psychology not as a social science but as a biological one, to assess philosophical thinking in terms of its understanding of mind as organic rather than machine, and to muse at the incredible and not always beautiful variety of human thinking, action, and culture. It also means taking stock of human religious or, better, spiritual experience and of the reductionistic materialism of some, even most, good science. Both spiritual and scientific experience place a premium on our ignorance: of our poor understanding of the origins of life and mind, of our lack of knowledge about the universe, its origins, its inclusion of dark matter, and what a difference the scale of measurement makes, and finally, as William James endeavored over a century ago, what to make of the varieties of religious experience. I have the good fortune to live during a time when such questions are meaningful and intellectual freedom permits such enquiries for the most part.
An important assumption here, as trivial as it may seem, is that humans are animals. If you listen to how many others address this matter, you will frequently hear about “humans and animals,” even in scientific discourse about “studies in humans and animals.” The missing word “other” here is a logical necessity in my mind. I do not think people say they are going to buy or to study “apples and fruit” in quite the same way. Separating ourselves from the rest of the animal kingdom seems a normal enough reaction to our symbolic capacity with its consequences for our consciousness, art, science and engineering. Separating ourselves from the animal kingdom seems to me a religious error and the source of a rationalization used in justifying slavery, racism, sexism, cruelty and other inhumane acts.
However, kinship cannot be denied, especially today when genetic science shows how completely all of life on this planet is related. Going further, consider the story recently about a scuba diver leading a group of underwater tourists to watch stingrays off the Hawaiian coast. He noticed a dolphin swimming with difficulty around the humans. When he went away from his group, the dolphin approached him and exposed his difficulty, fishing hooks and lines entangled tightly around his fins preventing normal locomotion. The diver took out some diving tools (well prepared wasn’t he?) and began to cut the lines and try to extract the hooks. The dolphin not only permitted this but cooperated with it, at one point swimming to the surface for a breath and then returning for the diver to finish the job. A similar story is told of a whale who when freed from entangling net and ropes by divers swam around experiencing its regained freedom and then went and tapped each diver’s mask with its beak.
What is salient here is that the dolphin did not go to the stingrays seeking help and that he permitted a human with sharp tools and pliers to cut away at line and remove a hook. The whale did not thank the divers’ hands but their faces. Even more than the prosocial, as we term it today, behaviors and engagement of the animals involved, I am fascinated by the connection between them, most assuredly a mental one, an empathic communication and establishment of some level of trust. Cetaceans have also evolved social and thinking brains and more will be said of this later, but consider this thought experiment. Tuna fisherman used to use nets that also captured and killed dolphins. Public outcry led to the development of different net designs and fishing practices to minimize this unwanted consequence. Thinking about this, placing oneself in the dolphin’s ‘shoes’ so to speak, finding oneself captured in a net with a bunch of tuna, ‘dumb’ fish you eat, in their situation, you work your way through the panicked mass and find yourself trapped by the net. The tuna struggle and exhaust themselves against the net to escape, but you, the dolphin can appraise the situation differently. You can see their futility and you can see the blue depths beyond where your freedom lies. Maybe you can seek the net opening to escape; more likely you will expire by drowning, understanding that freedom lies not in the struggle with the net but in the blue depths beyond. This is an anthropomorphic projection, I know, but not that far really from what cetacean understanding must be. Humanity depends upon such things.