Interior design psychology is a field within environmental psychology, which concerns the environmental conditions of the interior. It is a direct study of the relationship between an environment and how that environment affects the behavior of its inhabitants, intending to maximize the positive effects of this relationship. Through interior design psychology, the performance and efficiency of the space and the well-being of the individual are improved. Figures like Walter Benjamin, Sigmund Freud, John B. Calhoun and Jean Baudrillard have shown that by incorporating this psychology into design one can control an environment and to an extent, the relationship and behavior of its inhabitants. An example of this is seen through the rat experiments conducted by Calhoun in which he noted the aggression, killing and changed sexual tendencies amongst rats. This experiment created a stark behavioral analogy between the rat's behavior and inhabitation in high-rise building projects in the US after WWII, an example of which is the Pruitt-Igoe development in St Louis demolished in 1972 only 21 years after being erected.
Proxemics
Proxemics study the amount of space people feel necessary to have between themselves and others.
Crowding and personal space
In this field of study, the phenomenon of territoriality is demonstrated continuously through unwritten indices and behaviors, which communicate, the conscious or subconscious notions of personal space and territoriality. This phenomenon is seen, for example, through the use of public seating and the empty seats on a crowded bus or train. "Crowding occurs when the regulation of social interaction is unsuccessful and our desires for social interaction are exceeded by the actual amount of social interaction experienced." Studies observing social behaviors and psychology have indicated, such as in the case of commuters that people will seek to maximize personal space whether standing or sitting.
In a study conducted by Gary W. Evans and Richard E. Wene, (who work within the field of environmental design and human development) of 139 adult commuters, commuting between New Jersey and Manhattan, (54% male) saliva samples were taken to measure cortisol levels, a hormonal marker of stress. Their research accounts statistically for other possible stressors such as income and general life stress. "We find that a more proximal index of density is correlated with multiple indices of stress wherein a more distal index of density is not." Concerns arising from the results of this study suggest that small deviations in increased seat density, controlled against income stress, would elevate the log of cortisol (i.e. stress levels) and diminish task performance and mood.
Smooth and Striated space
According to Learning Spaces: Creating Opportunities for Knowledge Creation in Academic Life by Savin-Baden, it explored the concept of space in the physical sense when describing smooth and striated cultural spaces. Smooth spaces are described as "nomadic"; that is, in a constant state of movement. For example, the lobby of a hotel, an activity room where the seating directions are towards each other instead of focusing in one line, which provides a sense of relaxation and informality. These spaces are open, flexible, and owned by their inhabitants. Smooth spaces are where knowledge is contested and learning is co-created. They are messy and undisciplined, which often creates tension between stakeholders and users. Striated spaces, on the other hand, are described as bounded spaces, which refers to a certain orientation that focuses primarily in one direction, reflecting the organizational and pedagogical structure of the space. Classrooms and lecture halls are examples of striated spaces.
Relationships between people
Closely related to the proxemics of space, in the area of privacy. In "Perspectives on Privacy" P. Brierley Newell from the department of psychology at the University of Warwick, Coventry defines privacy as "a voluntary and temporary condition of separation from the public domain." The desire for privacy is often identified as a link between stress and distress. The ability to obtain privacy within an environment allows the individual to separate themselves physically and mentally from others and relax. This notion is of key importance in determining the behavior and well-being of the individual. As above in the scenario of crowding and density on public transport, privacy dictates the perception of comfort, in relation to crowding and personal space. Dissatisfaction with one's environment can be related to close proximity with others, leading to stress and as a result, diminish mood and performance behaviors.