Plants are frequently used as design components for various types of interior settings. Design professionals may specify plants because of a subconscious awareness of the human need for natural contact, or as in may cases, such as in a "sunspace", because it is traditional to do so. Past studies by behavioral and horticulture researchers have documented human preference for plants, and have shown that plants positively affect people psychologically, but little research has been done to determine whether the use of plants in interior environments can influence human behavior. Interior plantscaping is a vital and expanding type of agribusiness, with millions of dollars being spent each year to install and maintain plants specified by design professionals. Plants are frequently used for clients in industry, health care, hospitality, retail, education, and in personal residences. Demonstrating that plants influence human physical behavior in interior environments would increase their value as interior design components, and provide a powerful sales tool to the plantscaping industry. Because of the potential importance of understanding more about the influence of plants in interior spaces on human behavior, this research examines whether user behavior patterns and spatial perceptions can be changed by the simple addition of interior plantscaping. This study was conducted to determine whether the introduction of trees and plants into an underutilized area of a newly constructed interior atrium would affect user perceptions of, and/or behaviors in the space. User perceptions of and activities within the atrium were recorded on questionnaires and behavioral maps, both before and after the installation of Ficus trees and Chinese Evergreen plants. Surveys were used to collect demographic information, suggestions for improving the atrium, and to determine user perceptions via the use of 13 polar adjective pairs on a six point semantic differential scale. Maps were used to record user behaviors on the lower atrium level where the plants were placed. The majority of data were analyzed descriptively by frequencies and percentages. Semantic differential analysis was done using two-tailed t-tests at p = .05. T-tests did not prove to be significant. There was mean movement of perceived perceptions from pre- to post-test. User behavior on the lower atrium level appeared to be affected by plant installation. A preference was shown for napping under the trees, and users spent more time on that atrium level when the trees and plants were present. / Master of Science