Allow me to share...
Geoffrey Miller has been one of the foremost proponents of the role of sexual selection in human evolution. In essence sexual selection concerns mate choice: Those individuals who possess characteristics which are attractive to members of the opposite sex will be chosen as reproductive partners.
Sexual selection, is the accepted means by which particularly, extravagant traits have evolved in the biological world, such as the peacock's tail, the antlers of the extinct giant elk, and various parts of human anatomy which are involved in sexual attraction.
Miller has made a strong argument that the most extravagant entity of the biological world -- the human brain -- is also a product of sexual selection. Rather then its having evolved because bigger brains could process more information, Miller claims that the key feature of a bigger brain is its ability to come up with creative and novel behavior. He argues that neophilia, the love of novelty, is the most important feature of the human mind and claims that:
In modern society, human neophilian is the foundation of the art, music, television, film, publishing, drug, travel, pornography, fashion and research interests, which account for substantial proportion of the global economy. Before such entertainment industries amused us, we had to amuse each other on the African Savannahh, and our neophilia may have demanded ever more creative displays from our mates. This hypothesis can explain the mysterious cultural capacities that are universally and uniquely developed in humans sucah as language, music, dance, art, humour, intellectual creativity, and innovative sexual play.
Miller's proposal is that those individuals within early hominid society were able to engage in creative and novel behavior were particularly attractive to members of the opposite sex and hence were selected as mates. As a consequence those traits of creative thinking and bigger brains proliferated in future generations.
I really think this is an intriguing argument, although it hasn't been proven, its really interesting in theory. Funny thing is... I've always been teased for having a big head, so this theory is definitely in my favor. :-D
For those of you who are single, start seeking people that have big heads--they are more creative.