How do we find our way?

A Most modern navigation, such as the Global Positioning System (GPS), relies primarily on positions determined electronically by receivers collecting information from satellites. Yet if the satellite service’s digital maps become even slightly outdated, we can become lost. Then we have to rely on the ancient human skill of navigating in three dimensional space. Luckily, our biological finder has an important advantage over GPS: we can ask questions of people on the sidewalk, or follow a st...