Asymmetries of the Left and Right Temporal Lobes

Around 1861, after studying various cases of left hemisphere lesions and alterations in language, Paul Broca became convinced of the correctness of the studies of Mark Dax, which stated that language ability was localized on the left side of the brain, given that since 1877, it had already been considered that man, among all the other animals, had the most asymmetric brain with the largest quantity of acquired abilities, of which language was the highest, since it distinguished humans from animals. In this way, the concept was established that asymmetry is the defining characteristic of the human brain (Crow, 2004). This concept ran the risk of being lost during the 19 century, but reemerged in the second half of the 20 century due to the anatomical rediscovery of asymmetry by Geschwind & Levitsky (1968), in a study which compared the two sides of the brain, highlighting above all the asymmetry present in the left hemisphere.