Marc Berman on Attention Restoration, Nature, and Environmental Neuroscience

Environmental neuroscientist Marc Berman lays out the evidence that time in nature does not merely lift the mood but measurably restores the brain’s capacity to think — and asks what the low-level statistics of a natural scene have to do with it.

Key ideas

1. Directed attention is a depletable resource, and nature refills it. Attention restoration theory distinguishes directed attention — the effortful, self-controlled focus you spend deciding what to attend to — from involuntary attention, which interesting stimuli capture automatically. Directed attention fatigues with use; involuntary attention does not. An environment that makes few demands on the former while gently engaging the latter lets the depleted resource recover. Natural settings are one such environment.

2. The cognitive gain is real, objective, and separable from mood. In Berman’s within-subject studies, a roughly 50-minute walk in nature improved backwards-digit-span (working-memory) performance by about 20% — a digit and a half — where an urban walk did not. Participants who walked in freezing January weather and hated it gained the same cognitive benefit as those who walked in pleasant June. You must enjoy the walk to get the mood benefit; you need not enjoy it to get the cognitive one.

3. The effect is ‘softly fascinating’ stimulation, not leisure. Photographs, sounds, and videos of nature reproduce a weaker version of the effect, which points to the perceptual qualities of a scene rather than the holiday feeling. The restorative kind of stimulus captures involuntary attention while still leaving room to mind-wander — a waterfall, not Times Square. Berman calls this softly fascinating, as against the harshly fascinating pull of a city street or an addictive app.

4. Natural scenes are more compressible, more forgettable, and easier to process. Running JPEG-style compression (an algorithm tuned to human vision) over hundreds of images, Berman’s lab found that pictures people rate as more natural compress to fewer bits — they carry more repeated, redundant structure. Such images are also less well remembered, and statistically the compressibility explains the forgettability. Nature’s fractal structure — the same characteristic shape zoomed in or out — lets the brain grasp the gist cheaply.

5. Nature is a necessity for cognition, not an amenity — a case for city and building design. Green space near homes and schools tracks better attention in children after controlling for income; hospital patients with a window onto nature recovered from surgery a day faster on less pain medication. Berman’s frustration is that psychology has not quantified these gains in terms a policymaker can act on, so nature is treated as a luxury rather than infrastructure for human flourishing.

Summary

The bidirectional brain and the environmental-neuroscience programme

Berman’s field, environmental neuroscience, studies the two-way traffic between physical surroundings and the brain: our brains were shaped by the environment, we now design the environment, and that designed environment reshapes our brains in turn — all far faster than evolution can track. His wry point is that the very control humans hold over their surroundings breeds the illusion of immunity to them. Modern buildings are optimised to house people and move goods efficiently, never to make them more attentive or cooperative. The work is hard because you cannot cleanly randomise where people live, so conclusions have to be triangulated from many partial designs.

The nature walk: an objective cognitive dividend

Earlier researchers had shown people feel better after nature; Berman ran among the first studies to measure performance objectively. Using the backwards-digit-span task — hearing digits and repeating them in reverse, brutal past about five — participants were tested, walked roughly 50 minutes in either a park or a city street, and tested again, each serving as their own control a week apart. Nature walks produced about a 20% improvement; urban walks essentially none. Mood rose after nature too, but improved mood did not correlate with improved performance, and the January-versus-June contrast clinched it: misery in the cold cost the mood benefit but not the cognitive one. Repeated with clinically depressed participants primed to ruminate, the nature advantage was larger still — which is why physicians in the UK and Canada now prescribe nature walks as supplemental therapy.

Two attentions, softly fascinating

The theoretical spine is attention restoration theory, codified by Berman’s mentors Steve and Rachel Kaplan. Directed (top-down) attention is what you steer deliberately, and it fatigues — the 3 p.m. blur, the lecture hall drifting off at minute forty-five. Involuntary (bottom-up) attention is seized by bright lights and loud noises and resists fatigue; nobody tires of watching a waterfall. Restoration happens in an environment that spares directed attention while feeding involuntary attention with stimulation that is softly rather than harshly fascinating — engaging enough to hold you, loose enough to let the mind wander. This reframes attention: not a bucket that only empties, but a resource that some kinds of attending actively refill. It need not be nature — Berman allows that a light video game can qualify — but a dark room will not, because boredom is itself fatiguing; restoration is an active process, not mere rest.

What makes a scene restorative: compression, entropy, fractals

Because pictures and sounds of nature partly reproduce the effect, the cause seems to lie in perceptual features. Berman’s lab found natural images compress to fewer bits under a perception-tuned JPEG algorithm, are less memorable, and that the compressibility statistically accounts for the forgettability — a cheap-to-process scene need not be laboured over. Carroll pushes toward information-theoretic entropy: nature as low-surprise, low-entropy input. Berman refines it — pure white noise is maximal entropy yet not restorative, and a perfect Sierpinski-triangle fractal would be too boring. What restores sits at an intermediate complexity: predictable enough to grasp the gist, with just enough deviation — the bend in the path hiding what lies beyond — to stay softly fascinating. He connects this to the brain’s own signals, which grow measurably less fractal (their 1/f scaling breaking down) under hard cognitive effort, ageing, or distress.

From evidence to design

The payoff is practical and wide-ranging. Ulrich’s classic 1980s study found gallbladder-surgery patients with a nature view recovered a day sooner on less pain medication; green space around Chicago public housing, where families were near-randomly assigned, tracked better attention and less reported aggression. Berman frames access to nature as a staircase — real nature beats a window onto nature, which beats pictures, which beat nothing, with natural textures and even fake plants offering something. His candid limit: he could sketch a restorative school or hospital but could not yet tell a policymaker whether it is worth $20 million, because psychology has not translated a ‘20% gain in working memory’ into economic terms the way economics translates everything. Until it does, nature will be sold as an amenity when it is closer to a necessity. (The episode closes with a role-reversal ‘AMA’ in which Berman quizzes Carroll on many-worlds, free will, and consciousness.)

Speakers

• Marc Berman — guest; environmental neuroscientist and Professor of Psychology at the University of Chicago, director of the Environmental Neuroscience Lab and author of Nature and the Mind.
• Sean Carroll — host; theoretical physicist and author, Mindscape.

See also

• Sean Carroll — host
• Bing Brunton on the Connectome, Neural Computation, and How the Brain Controls the Body — a companion Mindscape conversation on the brain as an embodied, physical system
• Consciousness — the closing AMA turns to free will, consciousness, and emergence, and the body of the talk argues that the environment reaches into cognition