Right news, good news! The valence hypothesis and hemispheric asymmetries in auditory imagery

摘要

A Right Ear Advantage (REA) has been found during dichotic listening, but also in tasks requiring the sole imagery of auditory content, due to the left-hemispheric specialisation for language. According to the Valence Hypothesis (VH) the left (right) hemisphere would be also specialised in processing stimuli with a positive (negative) emotional valence. In a single trial imagery task, we asked 200 right-handed participants to imagine hearing in one ear a sentence with a positive or a negative valence, either in first or in second person. Results confirmed an imagery REA for the positively-valenced sentences, but no hemispheric asymmetries emerged for the negatively-valenced sentences (both in first and second person). We conclude that hemispheric asymmetries for language and for emotions interact during imagery tasks: the right-hemispheric superiority for negative emotions balances the left-hemispheric superiority for language, resulting in the absence of hemispheric asymmetries when a negative emotional content is imagined.