Dr. Marc Berman on Huberman Lab: How Nature Restores Focus

Berman distinguishes between directed attention—effortful focus we use to read, work, inhibit impulses—and involuntary attention, which is automatically captured by interesting stimuli (e.g., a waterfall, loud noise). Directed attention fatigues after sustained use (e.g., late in the workday, students nodding off mid-lecture), leading to poor impulse control, more aggression, and reduced goal pursuit. Modern environments—constant notifications, social media, dense urban stimuli—continually draw on directed attention, leaving people feeling “mentally tired” even when physically rested.

In a core 2008 study, participants completed a demanding working-memory task (backwards digit span), then took either a ~50-minute walk through an arboretum or a busy urban street, and repeated the task. The same individuals showed ~20% improvement in working memory and directed attention after the nature walk, but not after the urban walk, in a tightly controlled within-subject design. Crucially, mood improvements did not explain the effect, and even unpleasant winter nature walks (participants reported being “freezing” and not enjoying them) yielded the same cognitive benefits as pleasant summer walks.

Short lab exposures—about 10 minutes of viewing slideshow images of nature vs. urban scenes, or listening to nature sounds vs. urban noise—also improved working memory, though effects were smaller than real-world walks. Even hospital patients with modest window views of trees recovered from gallbladder surgery a day earlier and used less pain medication than those viewing a brick wall. Indoor plants and even high-quality nature photographs can provide some of the same ‘softly fascinating’ qualities when actual outdoor access is limited.

Natural environments are rich in fractals—repeating patterns across scales (tree branches, coastlines, mountains, snowflakes). Berman’s lab showed that nature images are more ‘compressible’ by JPEG algorithms than urban images, implying more redundancy and predictability: the brain can ‘throw away’ more detail while maintaining a coherent perception. People also remember nature scenes less accurately than urban ones, suggesting they are easier to process and less cognitively sticky. Brain activity in more rested, efficient states tends to be more fractal in time; Berman hypothesizes that nature exposure nudges brain dynamics toward this higher-fractal, lower-effort regime.

Scrolling social media, watching TV, or juggling texts feel low-effort but continue to draw on and fragment directed attention. Evidence from TV research shows people often feel more fatigued and irritable after extended viewing, and cognitive performance worsens. Berman emphasizes that ‘low cognitive load’ does not equal ‘restorative’: activities like social media are “harshly fascinating” and attention-grabbing in an all-consuming way, more like Times Square than a waterfall, continually draining the same attention resources you’re trying to replenish.