ARE WE GETTING DUMBER? Human Brain Size and Behavior Over the Past 20,000 Years


Over the past 20,000 years, the volume of the human braincase has shrunk–as much as 10%, by some estimates. Some experts say that this shrinkage just mirrors a shrinkage in body size resulting from poor nutrition in farming societies. Others believe that evolution has worked to conserve calories by making the human brain smaller and more efficient, with no loss of function. But other scientists think that we are actually getting stupider, as a result of “self-domestication” or increased population density. Is this shrinkage real? If it is, what does it mean?

Two leading experts on human brain evolution–Dr. Ralph Holloway (Columbia) and Dr. Robert D. Martin (Field Museum of Natural History) will debate and discuss this question on Monday, May 5 at 3:00 PM on the BU Campus. You can read their preliminary statements here (see below) and watch their conversation and the following panel discussion with a live audience on this site after May 7. If you wish to attend and participate, contact Dr. Matt Cartmill (


Read Dr. Martin’s statement here.

Read Dr. Holloway’s statement here.

 Read additional readings by Martin and Holloway here.


May 5, 2014  3 PM