The right-hemisphere and valence hypotheses: Could they both be right (and sometimes left)?

William D.S. Killgore, Deborah A. Yurgelun-Todd

Research output: Contribution to journalArticlepeer-review

187 Scopus citations


The two halves of the brain are believed to play different roles in emotional processing, but the specific contribution of each hemisphere continues to be debated. The right-hemisphere hypothesis suggests that the right cerebrum is dominant for processing all emotions regardless of affective valence, whereas the valence specific hypothesis posits that the left hemisphere is specialized for processing positive affect while the right hemisphere is specialized for negative affect. Here, healthy participants viewed two split visual-field facial affect perception tasks during functional magnetic resonance imaging, one presenting chimeric happy faces (i.e. half happy/half neutral) and the other presenting identical sad chimera (i.e. half sad/half neutral), each masked immediately by a neutral face. Results suggest that the posterior right hemisphere is generically activated during non-conscious emotional face perception regardless of affective valence, although greater activation is produced by negative facial cues. The posterior left hemisphere was generally less activated by emotional faces, but also appeared to recruit bilateral anterior brain regions in a valence-specific manner. Findings suggest simultaneous operation of aspects of both hypotheses, suggesting that these two rival theories may not actually be in opposition, but may instead reflect different facets of a complex distributed emotion processing system.

Original languageEnglish (US)
Pages (from-to)240-250
Number of pages11
JournalSocial cognitive and affective neuroscience
Issue number3
StatePublished - Sep 2007


  • Affect
  • Emotion
  • FMRI
  • Faces
  • Neuroimaging

ASJC Scopus subject areas

  • Experimental and Cognitive Psychology
  • Cognitive Neuroscience


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