Military vehicles painted with high-contrast geometric patterns can perturb enemy combatants’ perception of the vehicle’s speed and therefore the accuracy of any attack.
The study represents the first scientific proof that so-called ‘dazzle camouflage’, used in the First World War and Second World War, can in some instances be effective.
Our perception of speed is affected by many disparate factors: for example, larger objects appear to move more slowly than smaller objects; changes in contrast alter perceived speed; and differently oriented textures can be seen as moving at different speeds.
In a set of experiments, Dr Scott-Samuel from the University of Bristol showed participants two moving patterns on a computer screen and asked them to report which one moved faster.
One pattern was always plain and the other was selected from a typical range of textures used in dazzle camouflage: stripes, zigzags and checks. The stimuli moved either slowly or quickly, and could be either low or high contrast.
When moving quickly, two of the high-contrast patterns caused a significant reduction in perceived speed of around seven per cent. These patterns — zigzags and checks — were two-dimensional, in contrast to the other, one-dimensional, patterns tested.
Patterns that were less visible (low contrast) or slow moving had no effect on perceived speed, indicating that the effect is not simply due to texture per se, and implies that straightforward background-matching camouflage (which is generally lower contrast) would not produce a speed distortion. Thus, high-contrast texture, as used for dazzle camouflage, is necessary to produce this effect.
Scott-Samuel said the effect could be useful on low-tech battlefields, where handheld weapons are fired from short ranges against fast-moving vehicles.
‘We show that in a typical situation, involving an RPG7 attack on a Land Rover, the reduction in perceived speed would be sufficient to make the grenade miss where it was aimed by about a metre, which could be the difference between survival or otherwise for the occupants of the vehicle,’ he said.