A statue, a bench or something else we can see up ahead along our path draws us forward. What about something we can’t see? It turns out that mystery, properly displayed, is a prime human motivator, especially when we are on a leisurely stroll.
Mysteries offer invitations to explore, invitations that we adore.
Rachel and Stephen Kaplan, environmental psychologists who’ve studied human landscape preferences for decades, explain that exploration satisfies our basic need to understand our environment as a matter of survival and as fodder for our oversized brain and its need to know things.
Exploring itself takes two broad forms: Either traveling to some farther, as yet unknown place or examining something nearby in greater detail. I’ll characterize these two approaches as extensive exploration and intensive exploration.
Intensive exploration is prompted, and satisfied, by complex things that can be examined from a path. Almost any natural object qualifies because almost all natural things are fractal, and fractals offer new details at every scale of closeness.
In a similar way, much of the detailed artistry of Japanese landscapes and Chinese scholar gardens rewards this kind of exploration. Even manmade borders, such as historic city street edges, provide nearby opportunities to explore finely wrought facades and their details.
By contrast, the smooth Euclidian geometry of most recently machined objects, especially of expansive, blank modern building walls, repel up-close exploration so much that they actually deter nearby walking.
As for extensive exploration, Appleton takes our love for new information to its logical conclusion; we are most attracted, he argues, to places that promise the most new information. These places include sudden shifts along a route, such as where field meets woods, or where a sidewalk exits a plaza.
Appleton thinks the most prized destinations are far viewing points―a tower or hill on a far horizon, from which places the greatest amount of scenery farther on will be visible. He calls these especially attractive places for further exploration secondary vantage points.
The thing that all these farther viewpoints have in common is that they occur in concave spaces, that is, spaces that contain a bend, which hides part of the space around a corner or over a horizon.
The moment a bordering wall angles outward or the path’s treadway bends downward, some part of the path corridor becomes hidden from some viewing point. The edge that juts into the view is known as the casting edge. From that point outward projects a sightline that demarks the limit of what the walker can see, known as the occluded boundary.
Because things behind that limiting sightline remain hidden, it is also known as a lurk line. The view across such a bend might also be known as the exploration line, since it invites moving forward to see what lies hidden. Appleton called such a corner “a deflected vista [that] arouses curiosity and stimulates anticipation.”
We move forward, however, only if the likely value of what will be revealed warrants the effort of reaching it and exceeds our expected exposure to danger. If the distance is around a short curve in the path, we sense little risk but great interest. If, by contrast, we are aiming for a tower on the horizon, we sense greater reward but also greater risk—from vantage points like that we ourselves can be easily seen. And what of the route in between?
Context― a deep, dark forest, a dumpster-filled alley ―can augment our fears. Still, the context that makes us worry can be converted into a place of enticing mystery by good design, as by as by a sun-dappled path to the dense forest or by hiding the dumpsters and adding lights, trees, and windows to the alley.
Overall, research has found we will explore landscapes that can be read (to avoid getting lost), allow views to the sides (to avoid hidden threats), and grant physical access ahead (to avoid entrapment).
“As a concrete example,” researcher Thomas Herzog wrote, “gently curving paths with plenty of visibility in the bordering areas and a smooth ground texture throughout would satisfy most of these criteria.”