Global Matters Weekly – Gradually and then Suddenly

Spotting dangers and threats can be a difficult skill; not least because they often hide in plain sight. The physical act of literally seeing a danger can require a deliberate act of searching it out. For example an object such as a car or aircraft you are on a collision course with is often masked by the fact that the relative angle between you is constant, thereby it appears stationary. If the eye does not detect an angular change then it can be literally blind to it until the final moments before impact when its relative size in your field of view blooms to a large size, at which point evasive action can be too late. It is due to this optical phenomenon that to spot the danger we need to move our head around in our scan to create an angular change for the eye to spot.