A method and apparatus are provided to quantify psychological and physiological components to measure acute stress in humans, in which a stimulus can be applied to the test subject's environment during the test. The method involves multiple stress/relaxation intervals while physiological measurements are taken and "measured," and involves questionnaires that are answered after each of the intervals to "measure" the test subject's psychological state. A computerized testing apparatus acquires the physiological measurements, and also is used by the test subject in answering the questionnaires. The "stimulus" can be a fragrance, flavor, product, or task, and a "blank stimulus" is normally used during one of the stress intervals.