The "tongue map" and the pervasive idea that different areas of the tongue map to different tastes has been thoroughly debunked.
[url:19l983oq]http://www.livescience.com/health/060829_bad_tongue.html[/url:19l983oq]
[url:19l983oq]http://www.aromadictionary.com/articles/tonguemap_article.html[/url:19l983oq]
HOWEVER, there's some more modern information on how our sense of taste works that helps to explain "mouth feel" and spicyness from peppers and other tastes.
[url:19l983oq]http://www.asha.org/about/publications/leader-online/archives/2002/q4/f021022a.htm[/url:19l983oq]
Always good to know when it comes to sensory evaluation of those craft brews!
Adam