Simon Garfield, a journalist and author of On The Map: Why the World Looks The Way It Does, explains how with the advent of GPS we're losing not only the ability to get lost but we may be losing our spatial ability and perspective, and our ability to remember landmarks.

It is quite possible to walk, phones in our palms, from one end of a city to another without looking up. The loss is historical, social and monumental (as one inspired tweeter observed, I wouldn't change my Apple Maps for all the tea in Cuba). In our cars, GPS may guide us quite merrily from one country to another, and we may arrive at our destination without any idea of how we got there. En route from London to Cornwall, drivers may listen to a radio documentary about Stonehenge without realising that they have passed it on the right, for it is not on the sat nav. We now tend to look just a few yards ahead, which is a shorter distance than our ancestors used to gaze when they lived in caves.

There is another problem - digital maps may be shrinking our brains. Richard Dawkins has suggested that it may have been the drawing of maps, rather than the development of language, that boosted our brains over that critical hurdle that other apes failed to jump. Over the centuries, maps have always provided a key contribution and guide towards what makes us human, and they continue to record and realign our history.

It is still too early to say whether a lessening in our spatial ability and perspective, and our ability to remember landmarks, will decrease that area in our hippocampus that serves as the engine room for such skills, but it is highly likely. An examination of the brains of cab drivers has shown a great expansion in that area due, it is thought, to the retention of many miles of street plans.