Demaree, H.A.,
Everhart, D.E., Youngstrom,E.A., and Harrison, D.W. (2005)
Brain
lateralisation of emotional processing: historical roots and a future
incorporating 'dominance'.
Behav Cogn
Neurosci Rev, 4, 3, 3-20
Quite a
lot of information included from a psychiatric perspective, mostly ignored in
this summary.
Historically
4 sequential theories, hemisphere specialisation, valence, approach/avoidance
and dominance. Ideas of emotional
dominance should be explored further. Valence ideas mostly subsumed, by these
authors at least, into an approach/avoidance model.
Hemisphere specialisation (and then) the Valence model
Right
hemisphere specialisation for the perception of emotional expressions. Work
based mainly on the study of emotions with negative valence eg sadness. (some
more recent reports suggest that the left hemisphere is specialised for
positive emotions and the right for negative emotions ie the valence theory.
Furthermore a variant of this hypothesis contends that differential
specialisation exists for the expression and the experience of emotion as a
function of valence. Anterior regions of each hemisphere being specialised for
the expression and experience of emotion (- or +) depending on valence whilst
the posterior regions are specialised for perception of emotion
Most of
the evidence refers to either emotional
facial expression or affective prosody.
Evidence
from patients with right hemisphere lesions ( Adolphs, Damasio, Tranel
&Damasio, 1996) eg aprosodia ( both sensory and motor) typically observed
following right hemisphere lesions
Experimental evidence from participants who do not have
hemisphere damage ie left visual field superiority for discriminating emotional
faces
'consistent findings have been documented among patients
undergoing intracarotid sodium Amytal procedures ...... Affective faces rated
as less emotionally intense (compared to a base line) when shown to the
anaesthetised right hemisphere, but not when shown to the anaesthetised left
hemisphere
Electro physiological
'fMRI studies have found evidence of the specialisation of
right hemisphere structures for the perception of emotion'
Left half of the face is more active than the right during
emotional expression . The lower proportion of the face is predominately
innervated by the contra lateral hemisphere...... suggesting right hemisphere
control of facial expression (49 studies).
See bottom left paragraph of page 5 for the debate about
the spontaneous versus posed neural pathways.
Experience of emotion (mood
and affect)
Sodium Amytal, right carotid, indifferent, left carotid,
catastrophic.
Patients with right hemisphere lesions tend to lack prosody
Experimental studies combined with electrophysiological
monitoring
The approach- avoidance model
Overlap with the valence model is extensive ie most
negative emotions leads to avoidance.
Therefore left for approach and right for avoidance
Lots of EEG evidence, (asymmetry between left and right)
collected using all kinds of experimental paradigms.
Compared baseline frontal EEG activity to show that '
affective style (social initiation, positive affect versus isolated, onlooking
behaviour) is correlated with the expected frontal asymmetry based on the
location of approach/avoidance hemisphere specialisation
Anger studies - interesting because although a negative
emotion it leads to approach type behaviours. Frontal asymmetries (left greater
than right) recorded in children with impulsive disorders and also
experimentally induced anger in adults)
Ideas about dominance
p12 ' the current authors believe that the
approach-withdrawal model is compelling not only for its excellent fit to the
available data but also it's theoretical importance (ie to
species survival and procreation
). At the same time, however, we believe that the designation of
discrete emotions as 'approach' or 'withdrawal' is somewhat cumbersome. and the
strengths of the motivational impulse
can be quite difficult to quantify. In this last section, we make an
argument for using 'dominance' as an important state construct underlying
frontal asymmetry.
Circumflex model is relevant ' at least two dimensions are
required to describe affective experience. Valence ( + or - ) and arousal (low, high) most emotions can
be distinguished from each other using this model. Many emotion researchers use
the valence model to characterise emotional experience. (affective state).
Authors, and others, argue for a third dimension, dominance, 'feeling of
control and influence over everyday day situations. It would differentiate
between fear and anger ( both high arousal with negative valence) but each with
a distinct neural pathway. This idea
would fit with approach (emotional dominance) and avoid ( low emotional
dominance - aka submission)
