Encephalization quotient

The Enzephalisationsquotient (EQ) is a measure of the relative size of the brain, and is defined as the ratio of observed to expected brain weight for a given body weight of brain weight.

The EQ was in 1973 by H. J. Jerison developed to determine a quantitative relationship between brain weight and cognitive ability, taking into account other than the simple ratio of brain weight and body weight results Allometrie. The EQ but it is used for comparison of different animal species also in anthropology for comparison of different human species.

An EQ > 1 indicates that the brain is heavier than expected and may be indicative of increased cognitive abilities. However, the EQ is only very limited as a measure of cognitive ability. Firstly, it depends on the comparison group for which the expected brain mass is calculated, on the other hand are up and structure of the brain that are important for the cognitive abilities of great importance, not taken into account.

Calculation

The EQ is calculated as

The "expected brain weight " is an empirically determined size and depends on the kind of organism you want to compare means of EQ. Typically, it is found that the brain weight increases according to a power law with the body weight, the exponent. The literature values ​​are called by different groups of mammals or warm-blooded animals.

Examples

The man, in comparison to other animals to a very high EQ. EQ of warm-blooded animals is significantly higher than the other animals.