Examining the relationship between lateralisation for processing emotional faces, depression, and sex

Abstract

It is now relatively well established that the right hemisphere is specialised for processing facial emotion; however, there is variability in this pattern of lateralisation. One factor that has been examined is atypical lateralisation in individuals diagnosed with clinical psychological conditions. To date the evidence regarding the neuropsychological processing of emotional stimuli in individuals with depression is contradictory. In this study 160 participants completed the Beck Depression Inventory and the chimeric faces test, a test of lateralisation for the processing of facial expressions of each of the six basic emotions. A negative relationship between depression and lateralisation was found for females only, showing that women with higher depression scores tend to be less strongly lateralised to the right hemisphere, or even lateralised to the left hemisphere, for processing facial emotion. The strength of this relationship also varied across the different emotions with the clearest results for the processing of anger, disgust, and fear. There were no significant findings for males. The possible reasons for there being a sex difference in our findings and an attempt to reconcile the disparate findings within this area of research are discussed.

Keywords:

• Emotion lateralisation
• Chimeric faces
• Depression
• Sex differences

Notes

¹ Note that the directional scoring of the chimeric faces test (i.e., negative for left and positive for right) refers to the hemispheric bias, not the visual field. Consequently, a negative score reflects a right visual field (left hemisphere) bias and a positive score reflects a left visual field (right hemisphere) bias. While this directional scoring differs from some frequently used behavioural measures of lateralisation, such as line bisection, it is the typical method for scoring this particular test and the research in this field follows the hemispheric directional scoring (e.g., Kucharska-Pietura et al., 2002; Rahman & Anchassi, 2012).