HC 11
Chapter 31 – Emotional lateralization
The two brain hemispheres are not identical, there is so-called lateralization, which in other
words indicate that functional asymmetries of complex brain processes lead to differences
in hemispheric governance of e.g. emotions and other complex behaviors. Along these lines,
it appears the left hemisphere is more active in language, while the right is more active in
visual-spatial tasks and the emotional aspects of language. The facial expression,
emotionally, is thus also under control of the right hemisphere, meaning the left facial
musculature more fully expressed facial emotions than the right side of the face – as the
right side is governed by left hemisphere. Facial recognition is carried out by the right
inferior temporal lobe, whereby damage leads to impaired facial recognition or
prosopagnosia. Patients cannot identify the face of someone they have met.
Emotional lateralization becomes apparent in two ways:
- The right hemisphere is especially important in expression and comprehension of
affective aspects of speech. Lesions in the area most functional here, leads to
aprosodia; lose ability to express emotion by modulation of speech patterns. The
right is active in emotional coloring of language or prosody, so no matter what is said
or the meaning behind it, everything is monotone with aprosodia patients.
- The left hemisphere is more associated with positive emotions, while the right
hemisphere more with negative emotions – lesions in the left anterior hemisphere
more often lead to depressions.
Hemispheric asymmetry becomes apparent in healthy individuals during auditory
experiments when the right hemisphere is more dominant when detecting emotional
nuances in speech. Also, facial, emotional expressions are more detected when presented in
the left visual hemifield, the area the right hemisphere covers. Lastly, emotions are more
fully and quickly expressed with the left facial musculature. All in all, the right hemisphere is
more concerned about perception and expression of emotions. However, other lateralized
behaviors use both hemispheres – but to different extents. There is no dominant
hemisphere, one of the two is just more specialized in particular functions (language,
emotion, facial recognition, etc.) than the other. Always, both hemispheres participate in
the processes, there is just an efficient subdivision of complex functions rather than
superiority of one half. There are various other myths about the brain, like we use only 10%
at a time, or differences in hemispheric dominance explains individual differences among
learners. Every region of our brain is always and all the time, efficiently used for something
important.
Chapter 33 – Language lateralization
Language is the ability to associate arbitrary symbols with specific meanings to express
ideas, feelings, desires, emotions by thought, speech or writing. There is symbolic
representation of objects, concepts and feelings with communication as a goal. The
linguistic abilities of humans depend on several specialized areas located in association
cortices of the temporal, parietal and frontal lobes. Language lateralization gave rise to the
fact that the left hemisphere processes lexical, grammatical and syntactic aspects of
language, while the right handles the emotional contents.