Dynamic Dazzle Distorts Speed Perception

Abstract

Static high contrast (‘dazzle’) patterns, such as zigzags, have been shown to reduce the perceived speed of an object. It has not escaped our notice that this effect has possible military applications and here we report a series of experiments on humans, designed to establish whether dynamic dazzle patterns can cause distortions of perceived speed sufficient to provide effective defence in the field, and the extent to which these effects are robust to a battery of manipulations. Dynamic stripe patterns moving in the same direction as the target are found to increase the perceived speed of that target, whilst dynamic stripes moving in the opposite direction to the target reduce the perceived speed. We establish the optimum position for such dazzle patches; confirm that reduced contrast and the addition of colour do not affect the performance of the dynamic dazzle, and finally, using the CO2 challenge, show that the effect is robust to stressful conditions.

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

“…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). Our results indicate that misperception in speed may not always drive the benefits of dazzle camouflage.…”

“…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.…”

“…However, it has been suggested that motion dazzle camouflage may act through the manipulation of perceived speed (Hall et al., 2016, Murali and Kodandaramaiah, 2016, Scott-Samuel et al., 2011, von Helversen et al., 2013). If motion dazzle camouflage introduces inaccuracies in the observer's perception of object speed, any harm accrued through oddity in individual speed may be minimized.…”

Dissociation between perception and smooth pursuit eye movements in speed judgments of moving Gabor targets

“…It is well known that speed and direction perception can be affected by the internal motion of a moving target whilst a participant is fixating at a specific point (Hisakata, Terao, & Murakami, 2013;Hughes, Fawcett, & Tolhurst, 2015;Lisi & Cavanagh, 2015;Shapiro, Lu, Huang, Knight, & Ennis, 2010;Zhang, Yeh, & De Valois, 1993). One recent study has shown quantitatively that speed judgments can also be biased in a similar manner while tracking the target (Hall et al, 2016). Furthermore, it is known that steady state smooth pursuit to this type of second order stimulus is less precisely matched to the velocity of the target, particularly for relatively slow motion (18/s), and the resulting errors are corrected by saccades (Butzer, Ilg, & Zanker, 1997;Hawken & Gegenfurtner, 2001).…”

Diverted by dazzle: perceived movement direction is biased by target pattern orientation

“…In addition, modelling work predicts that the striped patterns on zebra should cause visual illusions [13]. In the case of speed perception, experimental findings have suggested that static striped patterns do not significantly disrupt speed perception [14], but that internally moving striped patterns are able to bias speed judgements in a systematic way [15]. However, to date, there has been little work on whether the striped patterns on individual targets can cause trajectory or direction misperceptions.…”