Abstract
An attractive product successfully attracts people not only when it is first introduced, but also throughout its lifetime. A product's ability to maintain attractiveness is an important factor in the design of a long-life product. People perceive product quality by the use of different sensory modalities such as vision and touch. The dominance of a particular sensory modality to perceive product qualities may change over time during product use. Two aspects are involved in this type of time-series change: physical changes in the product and users' psychological changes during their experiences with a product. In this paper, we propose an experimental methodology that analyzes changes in effects with respect to design parameters in relation to certain sensory modalities and two aspects of change. We applied the methodology to the design of a face lotion container. We asked 30 female participants to use a sample daily for one month. Participants were required to record their opinions about the samples (online assessment). On the first day, one week, and one month later, we invited the participants to visit the laboratory and asked them to assess 24 samples that contained different visual designs, surface finishes, amounts of lotion, and surface conditions (offline assessment). Based on these results, we demonstrated that the significance of design factors that participants perceived by different sensory modalities qualitatively and quantitatively changed over time. In this case study of lotion container design, we discovered that the potentially significant effect of a delicate surface finish that provided comfortable tactile sensations regardless of surface conditions on quality perception during long-term product use.
