"That old right hemisphere has me in its spell-That old right hemisphere that you activate so well". Is it true? Is the right hemisphere of the human cortex the seat of love, from early attachment to adult romance to transference and countertransference in psychotherapy? Can it be true, as Alan Schore has claimed, that therapy is the right hemisphere of the client talking to the right hemisphere of the therapist? Ideas like these have been around since the time of "Drawing with the Right Side of the Brain" and similar publications. They're reflected in casual conversation when people claim to be a "right brain" or a "left brain" person (usually "right brain", because most don't think "left brain" is such a good idea).
It would be nice for us all if brain functions and emotion were that easy to describe, but many claims about the human right hemisphere are poorly-supported oversimplifications. The brain just doesn't work that way, with one part dealing with an isolated function and operating separately from other parts. Years of argument and investigation in the 19th and 20th centuries pitted this "cortical localization" view against a holistic "mass action" view, culminating eventually in the conclusion that most parts of the normal brain are connected to and function together with other parts. Areas of the brain have their specialties, but they also perform other functions, and other parts share in the specialties. To get away from this fact, you have to get down to the level of single neurons.
Take, for example, a study recently summarized in the "Editors' Choice" section of "Science" (12 June 2009, p. 1367). This study examined the auditory cortex (there's one on each side of the brain) and looked at its response to nonsense words spoken with five different emotional overtones-- anger, sadness, relief, joy, or neutrality. Different parts of the auditory cortex were activated by each of the emotional tones. What does this have to do with right and left hemispheres? Well, in human beings, about half of the neural messages sent from the right ear end up at the left auditory cortex, and the other half at the right auditory cortex. The same thing is true for the messages from the left ear. People with normal hearing in both ears use both sides of the brain to process both meaning and emotional significance of information coming from both ears.
Then what about Schore's claim that the right hemisphere does the emotional work? In a 2008 paper called " Modern attachment theory: The central role of affect regulation in development and treatment" (Schore, J.R., & Schore, A.N., Clinical Social Work Journal, Vol.36, pp. 9-20), Schore stated that "attachment communications are critical to the development of structural right brain neurobiological systems involved in processing of emotion..." (p.10), a statement that is a serious claim about an actual structural difference between the sides of the brain and between different people's brains. What information did Schore use to support this claim? The Schores cited about 10 sources in support, but on examination it appeared that not all of those sources were relevant to the claim. Two of the papers cited were reports of studies on rodents, whose brain structures and affectional patterns are not very similar to those of humans. One of the cited papers looked at patterns of brain functioning as humans looked at faces with different expressions, and reported that the left side of the brain apparently was activated as the person looked at the expressions of lower parts of faces, while the right hemisphere was activated as the person looked at expressions of the upper parts of the face. The fourth cited paper examined problems in recognizing and comparing faces as they were seen in adults who had been blind because of cataracts in their early lives but had had their vision restored-- not a finding that is necessarily relevant to normal development. These research reports, presented as if they were supporting evidence for the claim that the right hemisphere plays the major role in human emotional communication and processing, in fact did not provide good support for this idea.
Does this mean that Schore must be wrong in his statements about the importance of emotional life for early development, for later social functioning, and for psychotherapy? No, of course not. The two things have nothing to do with each other. It's possible to be wrong about brain functions and right about emotion. But this is another case where the plausible description of brain functions has been used to buttress an argument that can really be strengthened only by investigations of the basic emotional phenomena themselves. Brain functioning is of enormous interest, but facts about it are misused when they are chosen or omitted in order to build support for a theory.
[Sorry folks, I am still disabling comments because of the recent flamers.]