Definition of encephalization in US English:



  • An evolutionary increase in the complexity or relative size of the brain, involving a shift of function from noncortical parts of the brain to the cortex.

    • ‘The increased encephalization of the human fetus - the size of its brain and therefore its skull - compared with any other animal has meant that the female pelvis has had to expand even further to ensure safe passage.’
    • ‘For example, it is known that major increases in encephalization occurred only after the appearance of early Homo.’
    • ‘In 1973, Jerison attempted to establish a quantitative measure of intelligence with his concept of the encephalization quotient, which was the ratio of actual brain size to expected ‘average’ brain size.’
    • ‘The resulting degree of encephalization is unique, and clearly causes (and is probably also caused by) some qualitative differences in language, tools and social organization.’
    • ‘Moreover, a trend toward increased encephalization within many mammalian taxa is widely recognized.’