Limits...
Dazzle camouflage affects speed perception.

Scott-Samuel NE, Baddeley R, Palmer CE, Cuthill IC - PLoS ONE (2011)

Bottom Line: Here we show that dazzle patterns can distort speed perception, and that this effect is greatest at high speeds.The effect should obtain in predators launching ballistic attacks against rapidly moving prey, or modern, low-tech battlefields where handheld weapons are fired from short ranges against moving vehicles.In the latter case, we demonstrate that in a typical situation involving an RPG7 attack on a Land Rover the reduction in perceived speed is sufficient to make the grenade miss where it was aimed by about a metre, which could be the difference between survival or not for the occupants of the vehicle.

View Article: PubMed Central - PubMed

Affiliation: Experimental Psychology, University of Bristol, Bristol, United Kingdom. n.e.scott-samuel@bris.ac.uk

ABSTRACT
Movement is the enemy of camouflage: most attempts at concealment are disrupted by motion of the target. Faced with this problem, navies in both World Wars in the twentieth century painted their warships with high contrast geometric patterns: so-called "dazzle camouflage". Rather than attempting to hide individual units, it was claimed that this patterning would disrupt the perception of their range, heading, size, shape and speed, and hence reduce losses from, in particular, torpedo attacks by submarines. Similar arguments had been advanced earlier for biological camouflage. Whilst there are good reasons to believe that most of these perceptual distortions may have occurred, there is no evidence for the last claim: changing perceived speed. Here we show that dazzle patterns can distort speed perception, and that this effect is greatest at high speeds. The effect should obtain in predators launching ballistic attacks against rapidly moving prey, or modern, low-tech battlefields where handheld weapons are fired from short ranges against moving vehicles. In the latter case, we demonstrate that in a typical situation involving an RPG7 attack on a Land Rover the reduction in perceived speed is sufficient to make the grenade miss where it was aimed by about a metre, which could be the difference between survival or not for the occupants of the vehicle.

Show MeSH

Related in: MedlinePlus

Stimuli.(a)–(e) standards, (f) comparison. (a) horizontal, (b) vertical, (c) zigzag, (d) check, (e) plain, (f) 1-D Gaussian. Stimuli (a)–(d) were displayed at two contrast levels (6.25% and 100%); stimulus (e) was displayed at maximum luminance (95.4 cd/m2); stimulus (f) ranged from mean luminance (47.7 m2) to maximum luminance (95.4 cd/m2).
© Copyright Policy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC3105982&req=5

pone-0020233-g002: Stimuli.(a)–(e) standards, (f) comparison. (a) horizontal, (b) vertical, (c) zigzag, (d) check, (e) plain, (f) 1-D Gaussian. Stimuli (a)–(d) were displayed at two contrast levels (6.25% and 100%); stimulus (e) was displayed at maximum luminance (95.4 cd/m2); stimulus (f) ranged from mean luminance (47.7 m2) to maximum luminance (95.4 cd/m2).

Mentions: On each trial, subjects were presented with a two temporal interval, binary choice task, and reported (via a keypad) which of the two stimuli moved more quickly. The speed of the standard stimulus was constant in a given block (either 3.33 or 20.0 deg/s), whilst that of the comparison stimulus was varied from trial to triaby the APE algorithm [21] in order to home in on the point of subjective equality. The comparison stimulus had a one-dimensional horizontal Gaussian luminance profile (fig.2f), which allowed for fine adjustment of its speed.


Dazzle camouflage affects speed perception.

Scott-Samuel NE, Baddeley R, Palmer CE, Cuthill IC - PLoS ONE (2011)

Stimuli.(a)–(e) standards, (f) comparison. (a) horizontal, (b) vertical, (c) zigzag, (d) check, (e) plain, (f) 1-D Gaussian. Stimuli (a)–(d) were displayed at two contrast levels (6.25% and 100%); stimulus (e) was displayed at maximum luminance (95.4 cd/m2); stimulus (f) ranged from mean luminance (47.7 m2) to maximum luminance (95.4 cd/m2).
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3105982&req=5

pone-0020233-g002: Stimuli.(a)–(e) standards, (f) comparison. (a) horizontal, (b) vertical, (c) zigzag, (d) check, (e) plain, (f) 1-D Gaussian. Stimuli (a)–(d) were displayed at two contrast levels (6.25% and 100%); stimulus (e) was displayed at maximum luminance (95.4 cd/m2); stimulus (f) ranged from mean luminance (47.7 m2) to maximum luminance (95.4 cd/m2).
Mentions: On each trial, subjects were presented with a two temporal interval, binary choice task, and reported (via a keypad) which of the two stimuli moved more quickly. The speed of the standard stimulus was constant in a given block (either 3.33 or 20.0 deg/s), whilst that of the comparison stimulus was varied from trial to triaby the APE algorithm [21] in order to home in on the point of subjective equality. The comparison stimulus had a one-dimensional horizontal Gaussian luminance profile (fig.2f), which allowed for fine adjustment of its speed.

Bottom Line: Here we show that dazzle patterns can distort speed perception, and that this effect is greatest at high speeds.The effect should obtain in predators launching ballistic attacks against rapidly moving prey, or modern, low-tech battlefields where handheld weapons are fired from short ranges against moving vehicles.In the latter case, we demonstrate that in a typical situation involving an RPG7 attack on a Land Rover the reduction in perceived speed is sufficient to make the grenade miss where it was aimed by about a metre, which could be the difference between survival or not for the occupants of the vehicle.

View Article: PubMed Central - PubMed

Affiliation: Experimental Psychology, University of Bristol, Bristol, United Kingdom. n.e.scott-samuel@bris.ac.uk

ABSTRACT
Movement is the enemy of camouflage: most attempts at concealment are disrupted by motion of the target. Faced with this problem, navies in both World Wars in the twentieth century painted their warships with high contrast geometric patterns: so-called "dazzle camouflage". Rather than attempting to hide individual units, it was claimed that this patterning would disrupt the perception of their range, heading, size, shape and speed, and hence reduce losses from, in particular, torpedo attacks by submarines. Similar arguments had been advanced earlier for biological camouflage. Whilst there are good reasons to believe that most of these perceptual distortions may have occurred, there is no evidence for the last claim: changing perceived speed. Here we show that dazzle patterns can distort speed perception, and that this effect is greatest at high speeds. The effect should obtain in predators launching ballistic attacks against rapidly moving prey, or modern, low-tech battlefields where handheld weapons are fired from short ranges against moving vehicles. In the latter case, we demonstrate that in a typical situation involving an RPG7 attack on a Land Rover the reduction in perceived speed is sufficient to make the grenade miss where it was aimed by about a metre, which could be the difference between survival or not for the occupants of the vehicle.

Show MeSH
Related in: MedlinePlus