Color is a Tricky Concept. How people perceive color varies widely. Many factors can influence this, including environment (such as lighting), personal history or knowledge (such as cultural differences) and many others.
Lighting can be the biggest factor of all, if other variables match. If two people view the same color sample under different lighting conditions this can affect their perception. White light and yellow light, used to be the most recognizable contrasts for color. However, the advancement of different light sources, such as CFL or LED create an environmental variable.