Which hypothesis about the selective forces influencing brain size has the strongest supporting evidence?

Question

Quizplus · Accepted Answer

Both social complexity (A) and the use of tools and processing food (B) have strong supporting evidence as selective forces for increased brain size in humans. Social interactions and cultural developments require sophisticated cognitive abilities, which are supported by larger brain sizes. Similarly, the creation and use of tools, as well as the processing of food, demand advanced cognitive functions and problem-solving skills, which are facilitated by larger brains. These factors have likely worked in tandem to drive the evolution of larger brain sizes in human ancestors.

Which Hypothesis About the Selective Forces Influencing Brain Size Has