A neuroanatomical predictor of mirror self-recognition in chimpanzees

Soc Cogn Affect Neurosci. 2017 Jan 1;12(1):37-48. doi: 10.1093/scan/nsw159.


The ability to recognize one's own reflection is shared by humans and only a few other species, including chimpanzees. However, this ability is highly variable across individual chimpanzees. In humans, self-recognition involves a distributed, right-lateralized network including frontal and parietal regions involved in the production and perception of action. The superior longitudinal fasciculus (SLF) is a system of white matter tracts linking these frontal and parietal regions. The current study measured mirror self-recognition (MSR) and SLF anatomy in 60 chimpanzees using diffusion tensor imaging. Successful self-recognition was associated with greater rightward asymmetry in the white matter of SLFII and SLFIII, and in SLFIII's gray matter terminations in Broca's area. We observed a visible progression of SLFIII's prefrontal extension in apes that show negative, ambiguous, and compelling evidence of MSR. Notably, SLFIII's terminations in Broca's area are not right-lateralized or particularly pronounced at the population level in chimpanzees, as they are in humans. Thus, chimpanzees with more human-like behavior show more human-like SLFIII connectivity. These results suggest that self-recognition may have co-emerged with adaptations to frontoparietal circuitry.

Keywords: brain evolution; chimpanzees; lateralization; self-recognition; superior longitudinal fasciculus.

MeSH terms

  • Animals
  • Brain / anatomy & histology*
  • Brain / diagnostic imaging
  • Diffusion Tensor Imaging / methods
  • Female
  • Functional Neuroimaging
  • Gray Matter / anatomy & histology*
  • Gray Matter / diagnostic imaging
  • Male
  • Nerve Net / anatomy & histology
  • Nerve Net / diagnostic imaging
  • Pan troglodytes / anatomy & histology*
  • Pan troglodytes / psychology
  • Recognition, Psychology / physiology*
  • Self Concept*
  • White Matter / anatomy & histology*
  • White Matter / diagnostic imaging