We sense our surroundings generally, but we place a special focus on our fellow humans because, as the adage goes, “man is man’s greatest joy.” As with engaging our surroundings in general, our senses discern approaching people in a sequence, coming into play at different distances, which has a profound effect on the size and character of our favorite places for spending time indoors and out.
Jan Gehl, the Danish architect who has been studying and creating pedestrian friendly outdoor spaces for more than 40 years, has described the distances our senses engage other people in both Life Between Buildings (1971) and Cities for People (2010).
We can distinguish a person from a deer or a shrub at between 300 and 500 m (a quarter mile, more or less) depending on light and background. At 100 m (110 yds) we can discern motion and overall body movement. This is the usual limit for viewing outdoor concerts or athletic games, so all seats in stadiums are within 100 meters of the middle of the stage or field.
We can usually identify an individual at 50-70 m (55-75 yds). At this distance we can also read hair color and body language. To provide this experience in large stadiums, massive screens display enlarged video of the action.
At a distance of 22-25 m (70-80 ft), we can make out facial expressions and dominant emotions. Nevertheless, the effective limit from a stage to the farthest spectator in a concert hall or opera house turns out to be nearer 35 than 25 m (110 than 80 ft) because performers elevate their voices, exaggerate their gestures, and wear makeup to emphasize their expressions.
As a person approaches, we focus first on the overall body, then the upper body, then on the face and finally on parts of the face. In urban settings where people contacts are vital to street liveliness, two thresholds are key: within 100 m (110 yds) is the social field of vision, the arena where we can distinguish humans moving, and within 25 m (80 ft) we can decipher an individual’s facial expressions and emotions. When we say a piazza or open space has human scale, we are referring to one that extends horizontally 100 m (110 yds) or less across its longest dimension.
Meanwhile, our development as the human species has had a significant effect on the way we use our eyes to see side-to-side and up-and-down. We are most concerned with what stands or lies directly ahead of us and what might approach us obliquely from either side. To cope with these potential threats, our eyes focus best directly ahead and slightly downward, and our head moves easily from side to side. We are poorly adapted to looking up, requiring us to “crane our necks.” More than that, we recognize objects we see frontally more easily than we recognize them when seen from below. As a result, we seldom see the person hiding in the tree or the person looking at us from a third-floor balcony, unless we are at some distance.
Walking along sidewalks we tend to appreciate features and engage people primarily on the ground floor or the second story. If people and details are lacking at these levels, particularly on the ground floor, we will find the scene boring if not discomforting.
By shouting and gesticulating we can indeed engage people at windows or on balconies of the third, fourth, and fifth floors. With effort they can be involved with the life of the street. Higher up that is not possible. “Above the fifth floor,” Gehl quips, “offices and housing should logically be the province of the air-traffic authorities. At any rate, they no longer belong to the city.”