Re: how are our tastebuds tricked?,

Hi Hayden!

Great question!  Scientists in an area of biology called "psychophysics" 
have looked at this question, and come up with some very interesting 
answers.

The short answer to your question is yes.  When food coloring is added to a 
food, it changes peoples' perception of how that food tastes -- or if 
they're even willing to taste the food at all!

A great summary of these sorts of experiments can be found at this page: 
http://faculty.washington.edu/chudler/coltaste.html

The author of this site discusses a handful of experiments like the one you 
describe, where people describe red sugar water as "sweeter" than pink sugar 
water, or redder orange drink as "less natural."

Now, are your tastebuds being tricked?  Probably not.  Your tastebuds detect 
only a few qualities -- sweetness, sourness, saltiness, and bitterness, as 
well as a quality called umami (found in the additive MSG).  The neurons 
(nervous system cells) in your nose detect most of the flavors/aromas that 
we associate with foods.  Both tastebuds and nose neurons work by grabbing 
onto molecules found in the food.  Their ability to grab these molecules is 
most likely unaffected by color. However, your brain's *interpretation* of 
what those flavors mean *is* affected by color.

So, a glass of orange 7UP may have all of the flavors/aromas/tastes 
associated with 7UP, but the visual information of orange soda.  Your brain 
may override the taste/smell information and believe it's tasting orange 
soda, because all of your experience drinking soda in the past tells you 
that 7UP = clear, orange soda = orange.

I wonder how blue or green or brown soda might taste?

For more information on how your eyes, nose, and tongue work, check out the 
rest of the NeuroKids site: http://faculty.washington.edu/chudler/introb.html

Hope this helps,
Amanda Kahn
amandak@phy.ucsf.edu