The Partner Institute for Computational Biology in Shanghai (specifically, the Comparative Biology Group) has published results of a decades long study that points toward eating meat as the primary stimulus in human brain development.

Approximately 2 million years ago, the size of the human brain doubled. "This happened because we started to eat better food, like eating more meat," according to PICB researcher Philipp Khaitovich. After that, little changed for a very long time.

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Only about 150,000 years ago, tremendous strides in cognitive thinking began to occur. Humans began inventing complex tools. Researchers also believe this time period to be the start of abstract thinking such as religion and creating art.

By comparing DNA from primate and human fossils and the differences in brain function, the PICB has come to the conclusion that changes in metabolism and food preparation are likely to be responsible for the developmental changes. Cooking meat allowed for less energy to be expended digesting food (tissues are broken down during the cooking process) and more energy to be used for the internal functions of the brain.

Read the PICB's report "Metabolic Changes in Schizophrenia and Human Brain Evolution" in the August 2008 issue of Genome Biology here.

Or read the slightly easier to comprehend Fox News break down here.