All of the elements that have underpinned the development of human cognitive abilities -- encephalization
(the evolutionary increase in the size of the brain), tool use, teaching, and language -- have one key characteristic in common: The conditions that favored their evolution were created by cultural activities, through selective feedback.
The most functionally significant comparison between brain sizes is the encephalization
quotient (EQ), the expected brain size given the size of the body.
The Social Brain Hypothesis proposes that the complexity of living in group influences encephalization
in vertebrates, but this theory has not been critically tested in invertebrate species.
The process by which some species evolved larger brains -- called encephalization
-- is not well understood by scientists.
and Brain Organization of Mobulid Rays (Myliobatiformes, Elasmobranchii) with Ecological Perspectives.
and allometric trajectories in the genus homo: Evidence from the Neandertal and modern lineages.
In the course of evolution, as a result of encephalization
, the motor functions of particular elements of the CNS become more and more "fuzzy" distributed among spinal cord, cerebellum, basal ganglia and cortex.
Body size, body proportions and encephalization
in a middle Pleistocene archaic human from Northern China.
In the first-ever comprehensive analysis of its kind, a study guided by psychologist Lori Marino used computed tomography to investigate the pattern of encephalization
in some fossil cetacean species in the past 47 million years, and analyzed these data along with those for some modern species.
The full association of anatomical properties, language, tool making, encephalization
, self-awareness, and self-reflection that come together in true Homo sapiens may have emerged only gradually in time, and only at some point then involved the new relationship of humanity and God involved in the fundamental narrative of salvation history.
Thus, largely due to increased body size and encephalization
, early Homo gradually transitioned in two ways.
This led to a measure called the encephalization
quotient (eQ) that permitted a comparison across species of actual, observed brain sizes versus those that would be predicted purely on the basis of body size.