This report argues over the right and left hemispheres of the brain. The brain is divided lengthwise down the middle at the longitudinal fissure. Despite being separate, the two hemispheres communicate and share information with one another by the corpus callosum, a white bundle of nerve fibers. Both hemispheres work together to complete tasks, but each hemisphere specializes in or is in control of certain activities. The right hemisphere controls the muscles on the left side of the body and the left hemisphere controls muscles on the right side of the body. In almost all right-handed people, the left hemisphere controls language skills. The left hemisphere manages language skills in the majority of left-handed people as well; however, there are more left-handed people whose right hemisphere directs language than there are right-handed people whose right hemisphere directs language. Additional skills governed by the left hemisphere of the brain include math and logic. People who are left-brain dominant usually find it easier to learn parts of a new skill or idea first, and then relate the parts to the whole thing.
For centuries, the concept of the dichotomous brain has been addressed in philosophy, art and religion. Socrates, the ancient philosopher, classified mind into two parts, a reasoning part and a part without reason. Legendary theorists (e.g., Hobbes, Pavlov, and Freud) divided the brain into two categories: an ordered or directed half, and an unordered or nonconcrete half. Nobel Prize winner Roger Sperry, together with esteemed colleagues (Sperry et al. 1969), empirically derived that the human brain often functions as if it were two separate entities. By studying patients with epilepsy so severe that split-brain surgery was performed, Sperry et al. (Sperry et al. 1969) examined the subtle consequences of the discontinuation of communication between the left and right brain hemispheres thereby establishing hemisphericity empirically.
Sonnier and Sonnier (Sonnier, 1995) linked brain hemisphere preference with levels of achievement. Arguing for a greater understanding of individual differences, they noted that much research was still to be done regarding learning styles. Overt behaviors of individuals can be indicative of their learning style (Sonnier, 1995). Individuals with dominant left brain hemispheres tend to be more structured, organized and more logical. These individuals tend to utilize their motor skills without difficulty and prefer a more analytical approach to problem solving and may often downplay visual methods of processing. Conversely, individuals who are right hemisphere dominant tend to think more holistically, are often artistic, quiet, less reliant on words and logic, and may also be less organized.
Right hemisphere dominant individuals are more spatially oriented and creative in planning, decision making, and problem solving (Springer, Deutsch, 1998). Brain hemi- sphere dominance may also be related to right- and left-handedness. Research supports that most individuals have brain hemisphere dominance (i.e., preference), although some individuals seem to use both brain hemispheres equally, with approximately30% of adults having right-brain hemisphere preference. Recent research appears to be supporting a more complex interaction between hemispheres than previously thought (Springer, Deutsch, 1998).
The right hemisphere (RH) is considered to have a particular role in emotion processing in general (Gazzaniga, 2002) as well as in the processing of emotional language material in particular (Gazzaniga, 2002). Brain structures are partially specialised, and, for most of us, normal development means that our speech function, word formation and so on, develops in the left side of the brain, and damage to regions of the left temporal cortex (for example Broca's area) will produce speech deficits, whereas damage to the equivalent region in the right hemisphere will not. However, if this part of the brain is damaged in early childhood, then the equivalent region on the right side of the brain may take over. Schore (1994) documents the neurobiology of subjectivity and intersubjectivity, which he equates with the "experience-dependent self-organization of the early developing right hemisphere" (2003, p. 34). Furthermore, Schore notes that "the structural development of the right hemisphere mediates the functional development of the unconscious mind" (p. 34) and that the right hemisphere is the repository of Bowlby's unconscious "internal working models" of the attachment relationship (Bowlby, 1969).
The infant's development starts with touch, moves to visual dominance and the final stage of early emotional development of the brain is the development of a verbal self. It seems that the process of putting feelings into words enables the left and right hemispheres become integrated. When words accurately describe feelings, they can be blended into a coherent whole (Gerhardt, 2004).
In general, the equivalent region on the right side of the brain has slightly different functions associated with visual imaging and things of this sort, so there are differences. But the argument that somehow words are associated with cognition, whereas vision is associated with affect, emotion, is of course a myth. In almost all right-handed people, the left hemisphere controls language skills. The left hemisphere manages language skills in the majority of left-handed people as well; however, there are more left-handed people whose right hemisphere (Gerhardt, 2004) directs language than there are right-handed people whose right hemisphere directs language.
Additional skills governed by the left hemisphere of the brain include math and logic. People who are left-brain dominant usually find it easier to learn parts of a new skill or idea first, and then relate the parts to the whole thing. They frequently like words and symbols, and prefer orderly instructions and predictability. This does not mean that left-brain thinkers are not as good at things as right-brain thinkers are, just that their left-brain skills are better than their right-brain skills.
The brain's right hemisphere deals with visual and motor skills. The brain's right hemisphere recognizes faces, patterns, shapes, rhythm, color, and depth. It is also the side that is responsible for imagination (Gerhardt, 2004). People with a dominant right hemisphere usually find it easier to learn all of something new and then divide the whole into parts. Instead of order and predictability, a person whose right hemisphere is dominant tends to prefer direct experiences and is more spontaneous (often does not plan ahead).
Most of these over--simplifications have been outdated by the development of brain imaging techniques -- which have been able to show complex patterns of activation in different tasks. Interestingly, on average, men and women use slightly different regions of the brain in performing certain tasks, though without any average difference in performance outcome. For example, in many studies on autobiographical memory and decision-making, men show slightly different patterns of activity, and slightly greater activity in a particular region of the right hemisphere than women do, but both men and women complete the tasks in an identical amount of time.
The recent convergence of neuroscience and psychology is revealing how right-hemisphere mechanisms are integrally involved in attachment and the development of the self. Neuropsychiatry is establishing how the neurobiology of the developing mind in infancy may parallel with and be applied to the processes of psychotherapy. As insecure attachment--relational trauma--is fundamentally understood as emotion deregulation, these theorists and researchers are suggesting that the goal of psychotherapy is the psychobiological dyadic regulation of affect in more adaptive ways. This results in changing neural pathways in the brain, the right-hemisphere in particular.
Therefore, because there is a growing body of evidence that is demonstrating that unconscious regulatory functions are fundamental to psychological processing and overt behaviour, neuroscience is influencing a move in psychology--away from a long-standing focus on cognitive processes--to a convergence on emotion and implicit relational processes.
Bowlby, J. (1969). Attachment and loss: Vol. 1. Attachment. New York: Basic Books.
Corballis, P. M. (2000). An evolutionary perspective on hemispheric symmetries. Brain & Cognition, 43, 112- 117.
Gazzaniga, M.S., Ivry, R.B., & Mangun, G.R. (2002). Cognitive Neuroscience: The biology of the mind (2nd ed.). New York: Norton & Co.
Gerhardt, S., (2004). Why love matters: How affection shapes a baby's brain. New York: Brunner-Routledge.
Schore, A. (1994). Affect regulation and the origins of the self. Hillsdale, NJ: Lawrence Erlbaum.
Schore, A. (2003). Affect regulation and disorders of the self. New York: W. W. Norton & Company.
Sonnier I.L. and Sonnier C.B. (1995) Nurturing hemispheric preference through affective education, Journal of Instructional Psychology 22(2) 182-185.
Sperry R.W., Gazzaniga M.S. and Bogen J.E. (1969) Interhemispheric relationships: The neocortical commissures: Syndromes of hemispheric disconnections, in: Handbook of Clinical Neurology. Vinken P.J. and Bruyn G.W., Eds, Amsterdam: North Holland Publishing, pp. 273-289.
Springer S.P. and Deutsch G. (1998) Left Brain, Right Brain: Perspectives on Cognitive Neuroscience, (5th ed.), New York: W.H. Freeman and Company, New York.