That was the key process prompting large brains.
The Sahul which includes New Guinea and the Carpentian Sea and Northern Australia was the last remaing environmemt retaining dinosaur era fauna, remnants of which still remain. Most of the Indonesian platform and theSouth China Sea was also above water. It too was continental in scale. All this was tropical rainforest and rich coastal reefs. It wasthose coastal reefs that supported the rise of stable communities.