by EC South, BC Hohl, MC Kondo, JM MacDonald, CC Branas
Resource Type: Journal article
Source: JAMA Network Open 2018
Grades: High School
Can planting grass and a few trees improve mental health? Researchers answered this question using a surprisingly rigorous approach—a randomized controlled trial. More than 500 vacant lots in Philadelphia were randomly assigned to be greened, cleaned up, or left alone. Residents living near the greened lots reported feeling less depressed and less worthless, while simply removing trash had no measurable effect. The study suggests that thoughtfully designed green spaces can improve more than just the appearance of a neighborhood—they may also help improve the well-being of the people who live there.
Phenomena:
Human impacts on environment
Human health
DCIs:
LS2.C: Ecosystems dynamics, functioning, and resilience
LS4.D: Biodiversity and humans
ETS1.B: Developing possible solutions
Notes:
- Excellent example of a randomized controlled trial outside of medicine.
- Great opportunity to discuss correlation vs. causation.
- Before-and-after photographs (Figure 2) illustrate the intervention and make an excellent discussion starter.
- Connects ecology, public health, and urban planning.
- Could spark discussions about equity because the strongest effects were observed in neighborhoods below the poverty line.
Driving questions:
- Can changing a place improve people’s mental health?
- How could scientists test whether green spaces actually cause improvements in mental health?
- Why did the researchers compare greening with simple trash cleanup?
- Why is a randomized experiment stronger evidence than simply comparing two neighborhoods?
- What other benefits might result from transforming vacant lots into green spaces?
Topics: green infrastructure, mental health, public health, urban greening, and urban planning
Features: field study, map, p values, randomized control trial, and statistical tests