Hemisferiese spesialisering en die ervaring van emosie

Abstract

Hemispheric specialisation and the experience of emotion. In this research the findings of Schiff and Lamon (1989) were investigated to see whether they can be replicated and whether the difference between the findings of Schiff and Lamon (1989) on the one hand and Kop et al. (1991) on the other can be explained. Schiff and Lamon (1989) found that unilateral muscle contractions of the lower left and lower right halves of the face (with hypothetical activation of the contralateral hemispheres) cause negative vs positive emotions/emotions which are difficult to typify. Kop et al. (1991) could not replicate these findings and come to apparently conflicting conclusions. The specific aims of this research were: to ascertain whether contractions of the lower left vs the lower right halves of the face (with hypothetical contralateral activation of the right vs left hemispheres) can be differentially associated with the experiencing of negative/avoidance vs positive/approach emotions; to ascertain whether the manner of responding (verbal or non-verbal) plays a role in the findings of the above-mentioned research or not; to asce1tain whether gender is a relevant variable in the determination of the findings; to ascertain whether the manner of emotional categorisation (approach vs avoidance as opposed to positive vs negative) has an effect on the results. The basic hypothesis was tested in a intrasubject experimental design with 40 right-handed subjects (20 = men, 20 = women). The influence of response strategy was investigated by using in experiment A a verbal response strategy and in experiment B a non-verbal, multiple choice response format. The responses of men and women were analised separately. The responses of subjects after unilateral contraction of the facial muscles were categorised and analysed in two ways, namely on the grounds of valence (positive vs negative) and dimension (approach vs avoidance).

The results indicated that the phenomenon reported by Schiff and Lamon (1989) and disputed by Kop et al ( 1991) does exist, namely that unilateral left and right lower facial contactions differentially facilitate the development of positive and negative emotional experiences. This research therefore accepts the explanation of Schiff and Lamon (1989) for the above-mentioned phenomenon in terms of superiority of the contralateral neural pathways between the lower facial halves and the hemispheres, the activation of hemispheres by facial contractions and the difference between hemispheres with regard to their superiority in processing emotions of different valences. Sex differences are responsible for the seemingly incompatible results of Schiff and Lamon (1989) on the one hand, and Kop et al (1991) on the other, in that the phenomenon reported by Schiff and Lamon ( 1989) is clearly exhibited in mixed groups of male and female subjects, very clearly by men, but not by women. Response strategy may have a deleterious effect on evaluations of the effect of facial contractions on affective experiences and should therefore be controlled.