Dazzle camouflage, target tracking, and the confusion effect

Abstract

Lay SummaryThe influence of coloration on the ecology of moving animals in groups is not well understood. High-contrast stripes may act as “motion dazzle camouflage” by preventing predators from accurately tracking prey, particularly in groups. We used a computer study with human “predators” to investigate this and found that targets in groups with horizontal striped patterns were harder to track than the ones with conventional camouflage, and the benefit increased with group size.Twitter: @Camo_Lab

Dazzle camouflage and the confusion effect: the influence of varying speed on target tracking

“…This could mean that correct assessment of the heading and rotation of targets is of heightened importance in these studies. It could be that these represent the parameters that are influenced by parallel striped conditions (Hogan, Cuthill, et al., 2016). Several of the empirical experiments on dazzle camouflage have focused on the hypothesis that bias in perceived speed could represent the primary mechanism by which this type of coloration reduces predation risk (Hall et al., 2016, Hogan et al., 2016a, Murali and Kodandaramaiah, 2016, von Helversen et al., 2013).…”

“…Each trial, subjects were presented with sets of 1, 10, 30 or 50 moving squares which were constrained within a central area on the screen (268 × 268 pixels). Each square was 32 × 32 pixels in size, and the direction of movement of all squares from one frame to the next can be described as a correlated random walk (see Hogan, Cuthill, et al., 2016). The participant's task was to track the movements of a predetermined target square with a mouse-controlled on-screen cursor until the end of a 5000 ms moving period.…”

“…Each trial, the background upon which the objects were drawn was a trinary noise pattern (see Hogan, Cuthill, et al., 2016). There were three coloration treatments applied to the moving squares: one was a trinary pattern created in the same way as the background coloration (see Fig.…”

“…Motion dazzle camouflage consists of geometric high-contrast coloration and is hypothesized to interfere with an observer's accurate perception of speed and trajectory (Hall et al., 2016, Hogan et al., 2016a, Hogan et al., 2016b, Hughes et al., 2014, Scott-Samuel et al., 2011, Stevens et al., 2008, Thayer, 1909). In a recent study, Hogan, Cuthill, et al.…”

The key role of behaviour in animal camouflage

“…As yet, this idea has not been explored further but merits study. Finally, note that there may be interesting interactions between some camouflage types, motion dazzle, and other defences in group-living animals, for example the confusion and dilution effect (see for example Hogan, Cuthill & Scott-Samuel, 2016).…”