Effects of Indoor Plants on Self-Reported Perceptions: A Systemic Review

Abstract

Bringslimark, Hartig, and Pati conducted a literature review of empirical studies investigating the psychological benefits of indoor plants, all of which adopted an experimental design and were written in English. However, the researchers did not follow the rigorous Preferred Reporting Items for Systematic Reviews and Meta-Analysis (PRISMA) protocol. Additionally, the reviewed data were obtained at least a decade ago, and thus require an update. Therefore, the present article reports a systemic review of the quantitative empirical research (in English and Chinese) exploring the effects of indoor plants on subjective psychological perceptions. The information sources were mainly Web of Science (1900–) and WANFANG DATA (1980–), in which only empirical studies using quantitative methods were selected. The eligibility criteria were studies (1) involving any participants, (2) regarding indoor plants (real or surrogates) as an intervention, excluding those equipped with a power-driven biofilter, (3) involving comparators to facilitate within-subject and between-subject comparisons, (4) presenting psychological perceptions as outcome measures, and (5) of all study designs. The two authors collected 45 journal papers (with 50 studies in total). The (1) authors and publication years, (2) participants’ nationalities, sex, and age, (3) number of interventions, (4) duration of plant exposure, (5) participant–plant distance, (6) experiment room size, (7) room climate (i.e., lighting, temperature, and humidity), (8) study designs (i.e., experimental, field experimental, quasi-experimental, field quasi-experimental, or survey designs), and (9) self-reported perceptions (i.e., emotion, cognition, health, restoration, thermal comfort, productivity, and satisfaction) were identified and reviewed. These 50 studies were also analyzed for their quality. Most had moderate research quality. The synthesized results of the reviewed studies showed that the most noticeable effects of indoor plants on participants were increasing positive emotions and reducing negative feelings, followed by reducing physical discomfort. Because members of the general public today spend most of their time indoors and are faced with increasingly severe problems associated with physical–mental health and wellbeing, the application of indoor plants to improving people’s physical–mental health is worth exploring.

Association between indoor-outdoor green features and psychological health during the COVID-19 lockdown in Italy: A cross-sectional nationwide study

“…These results are of considerable importance for the extension of previous literature on health conditions in the living environment, such as the home and workplace ( Dreyer et al, 2018 ). For example, the presence of plants in working environments seems to reduce perceived stress and, in general, to promote positive emotions and reduce negative feelings ( Han, & Ruan, 2019 ). Interestingly, our results are inconsistent with those reporting associations between presence of indoor plants and lower level of anxiety ( Hassan et al, 2018 ; Toyoda et al, 2020 ).…”

Does greenery experienced indoors and outdoors provide an escape and support mental health during the COVID-19 quarantine?

“…A second opportunity to engage with greenery at home is through indoor vegetation. Potted plants can reduce stress, physical discomfort, anxiety, and depressive symptoms ( Chang and Cheng 2005 ; Fjeld, 2000 ; Hall and Knuth, 2019 ; Han and Ruan, 2019 ) as well as increase attention ( Raanaas et al, 2011 ; Hall and Knuth, 2019 ; Kim et al, 2018 , 2020 ), mood ( Han and Ruan, 2019 ), and cognitive performance ( Adamson and Thatcher, 2019 ; Hall and Knuth, 2019 ). In one study, the mere presence of plants in the classroom also contributed to higher perceived restoration and positive affect of students ( Han and Ruan, 2019 ).…”

“…Potted plants can reduce stress, physical discomfort, anxiety, and depressive symptoms ( Chang and Cheng 2005 ; Fjeld, 2000 ; Hall and Knuth, 2019 ; Han and Ruan, 2019 ) as well as increase attention ( Raanaas et al, 2011 ; Hall and Knuth, 2019 ; Kim et al, 2018 , 2020 ), mood ( Han and Ruan, 2019 ), and cognitive performance ( Adamson and Thatcher, 2019 ; Hall and Knuth, 2019 ). In one study, the mere presence of plants in the classroom also contributed to higher perceived restoration and positive affect of students ( Han and Ruan, 2019 ). Another study found that students transplanting an indoor plant experienced reduced psychological and physiological stress and feelings of relaxation compared with working on a computer ( Lee et al, 2015b ).…”

“…Most previous studies on indoor greenery were related to workplaces, especially office spaces or classrooms ( Raanaas et al, 2011 ; Han and Ruan, 2019 ). In addition, studies conducted in experimental settings have yielded mixed findings ( Bringslimark et al 2007 , 2009 ).…”

Foliage colors improve relaxation and emotional status of university students from different countries

“…As beneficial outcomes of contact with nature are known, several studies has given to showing the significance of the natural spaces for human prosperity [7,8,9]. Studies have come to promising conclusions on the psycho-physiological impacts of green spaces [10,11,12,13,14,15]. Conservation of green spaces, in terms of quantity and quality, is an urgent global challenge in the face of growing urbanization [16,17].…”