Is human face recognition lateralized to the right hemisphere due to neural competition with left-lateralized visual word recognition? A critical review

Abstract

The right hemispheric lateralization of face recognition, which is well documented and appears to be specific to the human species, remains a scientific mystery. According to a long-standing view, the evolution of language, which is typically substantiated in the left hemisphere, competes with the cortical space in that hemisphere available for visuospatial processes, including face recognition. Over the last decade, a specific hypothesis derived from this view according to which neural competition in the left ventral occipito-temporal cortex with selective representations of letter strings causes right hemispheric lateralization of face recognition, has generated considerable interest and research in the scientific community. Here, a systematic review of studies performed in various populations (infants, children, literate and illiterate adults, left-handed adults) and methodologies (behavior, lesion studies, (intra)electroencephalography, neuroimaging) offers little if any support for this reading lateralized neural competition hypothesis. Specifically, right-lateralized face-selective neural activity already emerges at a few months of age, well before reading acquisition. Moreover, consistent evidence of face recognition performance and its right hemispheric lateralization being modulated by literacy level during development or at adulthood is lacking. Given the absence of solid alternative hypotheses and the key role of neural competition in the sensory-motor cortices for selectivity of representations, learning, and plasticity, a revised language-related neural competition hypothesis for the right hemispheric lateralization of face recognition should be further explored in future research, albeit with substantial conceptual clarification and advances in methodological rigor.

Let’s face it: The lateralization of the face perception network as measured with fMRI is not clearly right dominant

“…The challenge of future research will be to delineate potential factors driving hemispheric lateralization of fMRI activation patterns not only at the group level, but also in individual subjects. In other words, while decades of research investigated the underlying mechanisms of a right dominant face perception network (e.g., neural competition hypothesis with language areas, see Behrmann and Plaut, 2020, 2015; Dehaene et al, 2015, 2010; Rossion and Lochy, 2021) one should now address the question why – based on fMRI – roughly 50% of subjects do not show this so called “typical” pattern. Consequently, if it is totally normal for half of the population to present an atypical lateralization pattern, this brings up the questions whether lateralization patterns of individual subjects’ matter at all in terms of healthy brain function or disease.…”

“…In face perception research it is generally accepted that the right hemisphere is playing the dominant role (Duchaine and Yovel, 2015; Rossion and Lochy, 2021). This observation is based on ample evidence accumulated over the last decades with lesion patients, brain stimulation studies, and behavioral experiments.…”

“…The right-hemispheric dominance of the faceprocessing network was subsequently confirmed in various other studies. It is now based on ample evidence accumulated over decades of research with lesion patients, brain stimulation techniques or behavioral experiments (for an overview, see Duchaine and Yovel, 2015;Rossion and Lochy, 2021). Also the functional magnetic resonance imaging (fMRI) literature seems to confirm, at least at first glance, the right-hemispheric dominance of the face perception network.…”

“…The right-hemispheric dominance of the face-processing network was subsequently confirmed in various other studies. It is now based on ample evidence accumulated over decades of research with lesion patients, brain stimulation techniques or behavioral experiments (for an overview, see Duchaine and Yovel, 2015; Rossion and Lochy, 2021).…”

“…Bukowski et al (2013) replicated these findings and additionally showed that this reduced right-hemispheric lateralization was specific to the FFA, while OFA and STS were right-lateralized in both right- and left-handers, without a difference in the degree of lateralization. A possible explanation for this spatial specifity is often attributed to the left dominance of the visusal word form area (VWFA), a region associated with the identification of words and letters from lower-level shape images, prior to association with phonology or semantics (Dehaene and Cohen, 2011; Price and Devlin, 2003; for an overview also see Hildesheim et al, 2020; Rossion and Lochy, 2021). In another recent study, Frässle et al (2016a) combined fMRI and Dynamic Causal Modeling (DCM) to elucidate the neural mechanisms underlying the different hemispheric lateralization of face perception in right- and left-handers.…”