The report at the arXiv blog (read here), compares brains to computer chips.  There is a limit to the size of most computer chips because the larger the chip, the more cooling it requires.  The same can be said for our brains.  We encounter a size limit when the amount of energy required for cooling becomes unsustainable and inefficient.  Some computer chip makers say we are fools to produce faster and faster chips because of these inevitable cooling problems (once again, good news for anyone who fears a robot apocalypse).

But, calculations by theoritical neurobiologists show that our brains could be much larger.

Are our brains growing?  How can we tell?