Encephalization

Quotient Encephalization Quotient (EQ) is a measure used to compare the relative size of an animal's brain to the expected brain size for an animal of its size. EQ is calculated by dividing the actual brain weight of an organism by the expected brain weight for an organism of its size and body mass. A higher EQ reflects a relative increase in the size and complexity of the brain compared to other animals, indicating greater intelligence and more developed cognitive abilities. EQ can be used to compare different species, as well as to determine relative cognitive complexity within a species. It has been found useful for predicting species-level behavioral differences and for evaluating the evolution of higher cognitive functions, such as tool use and language.