Noun

(en noun)

(biology) the amount of brain mass exceeding that related to an animal's total body mass.

*{{quote-journal, 1998, date=June 12, Dean Falk, PALEONTOLOGY: Hominid Brain Evolution: Looks Can Be Deceiving, Science citation

, passage=The answer to this will determine the encephalization quotients of the two types of early hominids ( 8 ), which is an important indicator of relative "braininess," an issue that is now up for grabs. }}

*{{quote-journal, 1999, date=January 15, Matt Sponheimer & Julia A. Lee-Thorp, Isotopic Evidence for the Diet of an Early Hominid, Australopithecus africanus, Science citation

, passage=It is believed that the encephalization of early Homo was made possible by the consumption of energy- and nutrient-rich animal foods to "pay" for its metabolically expensive brain (39 , 40 ). }}

*{{quote-journal, 2001, date=November 2, Jerome M. Siegel, The REM Sleep-Memory Consolidation Hypothesis, Science citation

, passage=The time spent in REM sleep is not correlated with learning ability across humans, nor is there a positive relation between REM sleep time or intensity and encephalization across species. }}