Litter-strewn beaches aren’t just bad for the environment. They’re also bad for your mental health. Looking at a beach with garbage on it undermines the otherwise restorative quality of looking at nature, according to a new study published in the journal Environment and Behavior. It probably won't come as a surprise that looking at litter is a bummer. But it turns out our reaction to dirty beaches depends on the kind of litter we see. 

Kayleigh Wyles, an environmental psychologist at Plymouth Marine Laboratory in the UK, photographed beaches covered in plastic bags, empty bottles, and other detritus she had carefully placed in the sand (and later removed). She then showed the images to participants in three different lab experiments. Participants rated clean, pristine beaches as more restorative, calming environments than beaches that had trash on them. 

What kind of garbage was on the beach mattered, though. She found that viewers rated beaches covered in fishing-related litter more highly than beaches filled with old candy wrappers and bags of chips, in part because they viewed the latter group to be evidence of deliberate littering and a sign of disrespect, while they didn't hold old fishing nets to the same standard. People reported being angry or sad as they thought about the environmental consequences of the litter. But the site of a clean beach left them feeling happy and relaxed. 

Scientists have found increasing evidence that spending time looking at nature is good for mental health. An idea called attention restoration theory, first introduced in 1989, says that looking at natural scenery boosts concentration and decreases stress by providing a break from the constant psychological stimulation of urban environments, where there’s always something the brain wants to pay attention to.

But beaches that would otherwise be mental health boosters may not be as beneficial if they’re covered in shiny trash that prompts people to think about pollution and how humanity is killing birds and marine life by dumping 8 million metric tons of trash into the ocean every year. That's yet another good reason to join a beach cleanup. 

[h/t: Hakai]