Robert Sommer is best known for his pioneering work on personal space and proxemics, which he explored in his highly influential book, 'Personal Space: The Behavioral Basis of Design' (1969). He argued that personal space is not just a fixed distance around a person, but a dynamic, context-dependent boundary that regulates social interaction. His research demonstrated how the physical design of environments, from hospitals to classrooms, can significantly impact human behavior, making him a foundational figure in the establishment of environmental psychology as a distinct discipline.

For Robert Sommer, personal space is an invisible, portable territory surrounding an individual, which serves as a buffer zone to regulate social interaction and intimacy. He distinguished personal space from 'territoriality,' which is a fixed area. He found that personal space varies based on factors like culture, social status, relationship, and the specific situation. His research on seating arrangements, for example, showed that people adjust their personal space based on their relationship with others (e.g., sitting next to a friend vs. across from a stranger), demonstrating that it's a key mechanism in human communication and comfort.

Robert Sommer spent the vast majority of his academic career at the University of California, Davis, where he was a professor of psychology. He joined the faculty in 1963 and served for over five decades, founding the Environmental Psychology program at UC Davis. His position there was pivotal, as it allowed him to develop a comprehensive research agenda on the interaction between people and their environments. He was also a prolific author and a passionate advocate for using psychological research to inform design, architecture, and social policy.

Robert Sommer's most famous and influential book is 'Personal Space: The Behavioral Basis of Design,' first published in 1969. This seminal work brought the concept of personal space to a wide audience and was a landmark in the field of environmental psychology. In it, he synthesized his own experimental research with findings from anthropology, sociology, and animal behavior to explore how people use space to communicate. The book was highly praised for its accessible writing style and its practical implications for designing more humane and functional public spaces, buildings, and institutions.

A significant part of Robert Sommer's career was dedicated to studying and improving the design of mental health institutions. He argued that the physical environment of psychiatric hospitals and wards often inadvertently hindered the recovery of patients. Through his research, he identified how factors like furniture arrangement, lighting, and spatial density could increase or reduce patient stress and aggression. His work, including his book 'The Design of Mental Health Facilities,' provided concrete evidence and design principles for creating therapeutic environments that promote dignity, safety, and positive social interaction among patients and staff.

Robert Sommer drew a clear distinction between personal space and territory, which are often conflated. He defined personal space as a flexible, portable zone that surrounds an individual and moves with them, serving as a buffer zone for social interaction. In contrast, territory is a fixed, physical area that an individual or group claims, defends, and identifies with, such as a seat in a classroom, a neighborhood, or a country. While territory is a form of static spatial claiming, personal space is dynamic and situational, regulating the flow of social interaction.

Robert Sommer was a doctoral student of the renowned psychologist Roger Barker at the University of Kansas. Barker, the founder of ecological psychology, profoundly influenced Sommer's intellectual trajectory. From Barker, Sommer inherited a deep commitment to studying human behavior in its natural, real-world settings rather than in artificial laboratory environments. Barker's concept of 'behavior settings' inspired Sommer's focus on the relationship between the environment and behavior, which he applied specifically to spatial behavior, personal space, and the design of everyday places.