In Comparative anatomy, the term encephalisation corresponds to two Concept S distinct but connected. On the one hand, the encephalisation indicates the variation measured between the size of the Cerveau in a Espèce Animal E compared to the theoretical size calculated starting from the size of the remainder of the body. In a second direction, the encephalisation indicates phenomenon of increase in the size of the Cerveau, in particular compared to the remainder of the body, observed during the evolution. The concept of telencephalisation more precisely indicates the increase in the size of the Télencéphale which reflects the Pression of selection being exerted on the cognitive capacities organizations and in particular during the human evolution.

Coefficient of encephalisation

The idea that the evolution of many species, in particular of the mankind, was marked by a big raise of the size of the Encéphale emerged at the 19th century, in particular in work of Anatomiste S like Eugene Dubois or Louis Lapicque. The latter had thus managed to show that the size of the brain follows a Loi of power compared to the remainder of the body:

$e=c\; \backslash \; cdot\; s^\; \{R\}$

where $e$ (for Brain ) indicates the mass of the brain and $s$, the body Masse of the organization. The coefficient $c$ is known as coefficient of cephalization and $r$, coefficient of relation .