## 2 Theoretical Background
### Psychological Approach  
HCI research has developed based on various studies, primarily through psychological perspectives, to address multiple errors or build user-centered designs. The user research methodologies used in HCI research are primarily rooted in psychology as tools for understanding users who use products or services and know their world. Psychology is the study to understand human behavior, and the area used for that purpose is gradually expanding. Psychological approaches are beneficial for user-centered design in that they embrace ideas and knowledge built on multiple experiences and derive theoretical frames such as mental models. Constructivism is a theory of knowledge and learning in which the individual generates his or her knowledge, and constructs knowledge in the process of tackling problems [97; 98]. The theory of \"personal constructivism\" and \"radical constructivism\" has recently drawn new attention in the HCI field. Personal constructivism is also referred to as personal construct psychology (PCP) or personal construct theory (PCT), which originated with the pioneering work of [PERSON] [99]. [PERSON]'s theory of personal constructs was the first attempt to devise a theory of personality and psychotherapy based on a formal model of the organization of human knowledge [100]. He developed personal constructs to organize people's experiences, which predict how the world and individuals might behave [101]. In terms of PCP theory, they note that the external world has a significant impact on a person's constructions [101]. Radical constructivism (RC) emphasizes the ability of human beings to use the understanding they create to help them navigate life, regardless of whether or not such understandings match an external reality [102]. Furthermore, it rejects the possibility of objective knowledge because all knowledge depends on the knower's structure [103]. This notion of RC is mainly compatible with recent studies involving adaptive robots or autonomous agents, and for this reason, constructivism has recently gained attention again [104]. Various assessment techniques have been developed from PCP, divided into grid-based methods and non-grid-based methods [105]. The most famous method for grid-based methods is the repertory grid technique (RG) devised by [PERSON]. RG is the most widely used of all PCP-based psychological evaluation techniques [106] because it is closely related to PCP theory, can combine quantitative and qualitative analysis, can calculate multiple measurement ratings from the input data on a mathematical basis, and has good accessibility to statistics software [107]. RG builds a mental map of the world the user has into a subjective representation (language) of the individual [106]. In particular, from a design perspective, the goal of RG is to analyze elements, not subjects, and by analyzing the personal constructs generated with different participants, information such as perception-related consumer preference behavior can be obtained [107]. RG is a highly flexible method of data collection used in a wide range of research, including business, education, tourism, and forensic psychology [108]. [PERSON] and his colleagues revealed that the analysis of the RG provides useful qualitative information on progress at various stages of therapy, along with quantitative measures (such as self-ideal self-discrepancy as a measure of self-esteem) [109]. In research exploring the meanings of various kinds of outdoor spaces for people, they argue that the psychological meaning of constructing 'the natural' for individuals is different for each individual [110]. RG is also being used in the field of design. In research to collect user experience requirements in the early stages of product development, RG was used to derive more profound and more detailed user experiences [107]. In particular, in this work, RG is viewed as a useful user-centered design tool, as it is possible to derive detailed information that most users do not know themselves.