The right and left cerebral hemispheres are important for face and word recognition, respectively—a specialization that emerges over human development. The question is whether this bilateral distribution is necessary or whether a single hemisphere, be it left or right, can support both face and word recognition. Here, face and word recognition accuracy in patients (median age 16.7 y) with a single hemisphere following childhood hemispherectomy was compared against matched typical controls. In experiment 1, participants viewed stimuli in central vision. Across both face and word tasks, accuracy of both left and right hemispherectomy patients, while significantly lower than controls' accuracy, averaged above 80% and did not differ from each other. To compare patients' single hemisphere more directly to one hemisphere of controls, in experiment 2, participants viewed stimuli in one visual field to constrain initial processing chiefly to a single (contralateral) hemisphere. Whereas controls had higher word accuracy when words were presented to the right than to the left visual field, there was no field/hemispheric difference for faces. In contrast, left and right hemispherectomy patients, again, showed comparable performance to one another on both face and word recognition, albeit significantly lower than controls. Altogether, the findings indicate that a single developing hemisphere, either left or right, may be sufficiently plastic for comparable representation of faces and words. However, perhaps due to increased competition or “neural crowding,” constraining cortical representations to one hemisphere may collectively hamper face and word recognition, relative to that observed in typical development with two hemispheres.

The left and right cerebral hemispheres are important for word and face recognition, respectively—a specialization that emerges over human development. But children who have undergone a hemispherectomy develop with only one hemisphere. The question is whether this preserved hemisphere, be it left or right, can support both word and face recognition. Here, a large sample of patients with childhood hemispherectomy and age-matched controls performed word- and face-matching tasks. Controls viewed stimuli either in one visual field (restricting initial processing to one hemisphere) or, like the patients, in central vision. Across word and face tasks, patients performed comparably to controls using primarily one hemisphere, but more poorly than controls viewing stimuli centrally with both hemispheres engaged. Additionally, patients showed deficits in low-level visual processing that may explain their word/face recognition deficits relative to controls. Altogether, the findings suggest that either hemisphere alone can support word and face recognition, albeit sub-optimally.

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