Posted: Dec 16, 2012 10:20 pm
Look to toddlers for differences. There are a number of neat experiments that highlight the differences.
Here is one
http://www.lifeslittlemysteries.com/280 ... rucks.html
and some more formal stuff
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3030576/
Here is one
http://www.lifeslittlemysteries.com/280 ... rucks.html
and some more formal stuff
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3030576/