According to an article in Bro Bible, Don Katz, a neuropsychologist from Brandeis University, has proven that Skittles only have different colors and fragrances...not tastes! They wrote:
“…I don’t usually talk about gummy bears, what I like to talk about is Skittles,” Katz says. “The Skittles people, being much smarter than most of us, recognized that it is cheaper to make things smell and look different than it is to make them actually taste different.”
Katz continues: “So, Skittles have different fragrances and different colors — but they all taste exactly the same.”
Katz says this works because our brains are used to processing certain sensory cues together. For example, our brains associate the color yellow, a lemon smell and a slightly acidic taste with each other. When you’re offered two of these three sensory cues, your brain will fill in the blanks.