The effect of adaptive camouflage on perceived speed in neutral and stressful situations N Scott-Samuel1, J Hall1, I Cuthill2, R Baddeley1, A Attwood1, M Munafò1 |
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1Experimental Psychology, University of Bristol, United Kingdom |
| Static high contrast colouration – “dazzle camouflage” - can reduce perceived speed by around 7% (Scott-Samuel et al., 2011, PLoS ONE, 6(6):e20233). We investigated the effect of moving dazzle patterns on the perceived speed of a target that was itself moving. A drifting 100% contrast vertical sinusoidal grating increased perceived speed when moving in the same direction as the object it covered, and reduced apparent speed when moving against the object direction. This effect was largest (15% speed change) when the grating and object speeds matched, and persisted when: stimulus contrast was reduced to 6.25%; the area covered by the moving texture was reduced to 25% of the object’s surface (divided equally between the leading and trailing edges); the moving grating was replaced by a zigzag pattern; subjects inhaled 7.5% CO2-enriched air, a procedure known to induce anxiety. These data offer the intriguing prospect of multi-purpose camouflage: if dazzle colouration need not be high contrast, completely covering an object, or of a particular pattern, then it could be static and cryptic for a stationary object, yet also dynamic and speed distorting when the object moves. Furthermore, the stress manipulation suggests that our laboratory results may obtain in more realistic situations. |
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