Bigger human brain prioritizes thinking hub -- at a cost. Some human brains are nearly twice the size of others -- but how might that matter? Researcher have discovered that these differences in size are related to the brain's shape and the way it is organized. The bigger the brain, the more its additional area is accounted for by growth in thinking areas of the cortex, or outer mantle -- at the expense of relatively slower growth in lower emotional, sensory, and motor areas. Source 7a.
No I believe it has nothing to do with your brain size but how you exercise and use you brain. If you continue to learn and use your brain to get smarter then it does not matter if you have a smaller or bigger brain. If you have a bigger brain and do not use it then are you smarter than others?
We break from Does Brain Size Matter? to share caption from antiquity:
Today is: 17th January (GMT), in history on the 17th of January, 1861 AD the following event happened:
Flush toilet patented by Mr Thomas Crapper (Honest!)