IB Psychology – 2026 Biological Approach Practice Test: The Comprehensive All-in-One Guide for Exam Success!

Evidence for left-hemisphere language dominance in most right-handed people comes from lesion studies and neuroimaging. When language areas in the left hemisphere (like Broca’s and Wernicke’s areas) are damaged, people often develop aphasia, while damage to the right hemisphere does not produce the same pattern of language loss. Modern imaging (fMRI, PET) shows that language tasks reliably activate the left hemisphere more than the right in most right-handed individuals. This combination of behavioral evidence from lesions and imaging findings provides strong support for left-hemisphere localization of language. The other possibilities don’t fit as well: right-hemisphere language centers are not typical for most right-handers, language isn’t entirely bilateral with no specialization, and while the cerebellum supports language in some ways, it is not where language is primarily localized.