Two theories posit the restorative benefits of exposure to plants and natural settings, either in the form of stress reduction and improved mood, or through enhancement of cognitive performance, specifically attention processes. Research conducted on the latter area has used a wide variety of tasks to measure attention, often without consideration to underlying cognitive processes. The main purpose of this research was to examine the effects of natural stimuli on cognition and mood from a cognitive science perspective, using measures that assess specific underlying cognitive processes. The secondary objectives of the research were to explore the effect of natural stimuli on subjective well-being and examine whether different types of exposure would have distinct impacts on cognition and mood.

Four experimental studies were conducted in order to examine three exposure types: (1) window views of nature vs. buildings vs. control, (2) plants vs. other embellishments, and (3) two studies comparing the interaction with living plants to viewing pictures of plants. Dependent variables consisted of tasks used in the cognitive sciences to measure underlying cognitive processes of inhibition, working memory, creative problem solving, and sustained attention. Verbal working memory was measured using the Backwards Digit Span task and the n-back task. Sustained attention was assessed using a vigilance task. Executive attention processes of inhibition and creative problem solving were measured by the Stroop Task, and either the Remote Associates Test or the Abbreviated Torrance Test for Adults, respectively. Subjective mood state was examined using the Profile of Mood States ? Short Form and the Positive and Negative Affectivity Scale.

Quantitative statistical analyses revealed the use of dependent measures assessing specific cognitive processes produces results different from previous operationalizations of attention employed in other studies. Window views of nature enhanced creative problem-solving performance more than the building view or ?no-view? control, but did not influence sustained attention. Participants exposed to plants versus other office embellishments did not show better performance on a working memory task. In the majority of the studies, mood state was unaffected. Overall, the results suggest that more precise operationalizations of attention are required.