I was looking some stuff up about amphibians and started coming across all these articles on neoteny...then neoteny in humans....and sure enough, I wasn't the only one who connected this stuff to Japanese. (though not so sure I buy the whole rice theory)
http://fujiland-mag.blogspot.jp/2011/12 ... rever.html
Neoteny is a biological term that describes the retention of juvenile characteristics in adults, something that is widely recognized in the animal world. For example, we know that tadpoles mature into frogs, losing their juvenile aquatic character along the way. However, the axolotl species of salamander remains fully aquatic throughout its life, merely becoming a large version of a tadpole. A better known example of neoteny is the giant panda, which retains its baby-like cuteness into adulthood. Indeed, humans have juvenile characteristics relative to other primates. Our sparse body hair and enlarged heads are in fact reminiscent of baby primates.