Does the display of color affect the taste of food I have a science project where we are putting the exact same cookies on three different color napkins to see if the cookies taste different?

Visual appearance, including colour, does affect how people perceive the taste of food. In the project you mention you'd expect tasters to find differences between the cookies on different coloured napkins. However, in any similar experiment people will find differences between foods they're tasting even if, for example, you have identical cookies on napkins of identical colour and appearance. People involved in this kind of project expect to taste differences, so they do!