Cerebral asymmetry and emotion: Conceptual and methodological conundrums

Abstract

A diversity of methods have been used to study cerebral asymmetries associated with emotion. Many different conceptual schemes have also been invoked to guide research on this topic. The purpose of this article is to survey the critical methodological and conceptual issues in this area of research. Research in this area must acknowledge the multi-componential nature of emotion. Asymmetries associated with the perception of emotional information and the posing of emotional expressions are not necessarily the same as those that accompany the actual production of emotion. Asymmetries vary along the rostral/caudal plane both in their magnitude and direction, as well as in their functional significance. Research in this area must explicitly take this variable into account. Different measures of asymmetry do not reflect the same underlying process and so cannot be used interchangeably. In particular, behavioural measures which lack extensive localising validation, must be used with caution. Finally, the nature of the causal connection between alterations in asymmetric activation and emotion is not a simple one and extant data indicate that an asymmetric shift is not sufficient for the production of emotion. This fact has serious implications for the types of experimental designs that must be used to adequately test for relations between cerebral asymmetry and emotion. The article concludes with a discussion of some of the major outstanding questions that will occupy a central position in the future research agenda in this area.