Kansei engineering for product optimization
The main problem with conjoint analysis is the lack of an emotional or feelings assessment of the product. Conjoint merely provides an assessment of the materialistic or engineering aspect of a possible design. When you buy a product, you buy more than a material item; you also buy an attachment that transcends the material. A good example is the purchase of a new car. In a simplistic sense, the car is only a physical container composed of many individual physical items: metals, plastics, glass, rubber to mention a few. These are arranged in some fashion to create an object called an “automobile” or “car” that has speed, power, fuel efficiency, maneuverability, and safety. Other design elements, such as the appearance (i.e., the aesthetics), are also embedded in the car as part of the arrangement of the materialistic parts. These are additional important factors customers consider when purchasing a new car along with the materialistic combinations of the metals, plastics, glass and rubber. Because of both the materialistic and aesthetic aspects, people develop an attachment (or not) to a car so that it becomes an extension of themselves. See Sheller  for some discussion about the emotions associated with a car. Also see Edensor  for an interesting discussion about how national identity is also expressed by car and what the author calls “automobility.”
Jewelry is another product that has more aesthetic appeal than materialistic. Certainly for a diamond engagement ring, there is concern about the features of the diamond such as its rating on the “4Cs” of diamonds: cut, color, clarity, and carat weight. The shape and perhaps certification may also be important. But by and large, the emotions attached to giving or receiving that ring far outweigh these physical attributes. See Ahde 12010J for a study of the emotions attached to jewelry.
Clothing, foot apparel, and a house are other examples. You have a favorite shirt or blouse, or sneakers you believe make you look sexy, successful, powerful, independent, and so forth. A house shows status, success, lifestyle, and comfort but also embodies memories and emotions, good and bad. These examples illustrate an appeal that transcends purely physical characteristics. Conjoint analysis captures the importance and weight in total value or worth of the physical attributes, but the emotional aspects are absent.
There is research that shows that people form attachments to their material possessions that go beyond the physical attributes of those products, usually durable goods. Schifferstein and Zwartkruis-Pelgrim  argue that some products, such as cars, have a degree of irreplaceability, indispensability, and self-extension that transcend the physical attributes. They claim that there is an emotional bond that ties the product to memories, enjoyment, self-identity, life vision, and market value that new product designers should be aware of and should tty' to incorporate into their product designs. It may be difficult or next to impossible to incorporate some of these emotional aspects into a physical design (how do you incorporate “memories” or “self-worth”?) so they may be better left to the marketing messaging, a topic I discuss in Chapter 5. But yet for some products that are considered gifts, memories can be invoked or created by the product itself. An example is a silver platter given as an anniversary gift or a picture frame given as a wedding or graduation gift. Nonetheless, they should be considered rather than being either ignored or given scant attention simply because they are difficult to measure. See Schifferstein and Zwartkruis-Pelgrim  for some suggestions on how to incorporate emotions in new product design. Also see Sheller  for more comments on the role, extent, and importance of emotions regarding automobiles.
Since conjoint analysis is materialistically focused with the emotional aspect absent, another approach is needed that captures this emotional aspect. One such approach is called Kansei Engineering. “Kansei” is a Japanese word that implies “feelings” or “impressions” or “emotions”. The goal of Kansei analysis is to identify, measure, and incorporate emotional aspects of products in the new product design stage. See Matsubara et al. , Lai et al. , and Chuang et al.  for discussions and applications. Also see Lokman et al.  for proceedings of an international conference on Kansei methods and emotion research.