- Sensory evaluation is a scientific discipline involved in evoking, measuring, analyzing, and interpreting responses to properties of foods and materials as perceived by sight, smell, taste, touch and hearing. Historically, sensory evaluation test methods have been divided into two basic types, affective and discriminative. Affective tests involve acceptance tests, usually involving some type of scale or response (for example, a scale ranging from like extremely to dislike extremely) or preferences, where two products are presented and a person is to select which one is preferred. This affective type of test method is known to be 11 subjective" or to reflect a person's personal reaction to a food or material. Discriminative methods are analytical in nature and should be thought of as "objective" sensory methods. Discriminative methods fall into two main types: The first is where simple differences between samples are observed. This could be overall differences such as a difference in overall taste intensity or it could be specific to an individual attribute such as difference in sweetness or sourness (acidity). The other main type of discriminative sensory test is descriptive. Descriptive testing, or descriptive analysis, utilizes a highly-trained panel so that each panelist can be thought of as an analytical instrument. Because of the high degree of training, results from a descriptive analysis panel are very reproducible.