Fig 1.
Combined data for Experiments 1a (blue data points) and 1b (black data points). Data points are means and error bars represent standard deviations (N = 15 for each experiment). The target speed was 10 deg/s. The effect on the perceived speed of the target peaks at 10 deg/s. ‘Speed of dazzle texture’ is defined as relative to the target not the background.
Table 1.
Parameters and fit for the modelled relationship between speed of dazzle texture and change in perceived speed for the 10 deg/s target (Experiment 1) and the 5 deg/s target (Experiment 2).
Fig 2.
Data for Experiment 2 where the target speed was 5 deg/s.
Points are means and error bars represent standard deviations (N = 15). As in Experiment 1, the effect on perceived speed was greatest when the texture speed matched the target speed.
Fig 3.
White arrow indicates direction of target and red arrow indicates direction of dynamic texture motion. Red rectangle indicates the proportion of the texture that is moving. The remainder of the texture is static.
Table 2.
Experiment 3: Mean (±SD) change in perceived speed, compared to static dazzle control, and one-sample t-test results for different combinations of dazzle size and position.
Fig 4.
White arrow indicates direction of target and red arrow indicates direction of dynamic texture. Red rectangle indicates proportion of dynamic texture. The remainder of the texture is static.
Fig 5.
Mean (±SD) percentage change in perceived speed for Experiment 4 (N = 15 participants).
Dynamic texture was present only at the trailing edge of the target or at both ends (‘double’). *Indicates change in perceived speed is significantly different from zero. The effect on perceived speed was greatest for conditions where there was a patch of dynamic texture at each end (‘double’), even when the texture at the trailing edge covered an identical proportion of the target.
Table 3.
One-sample t-test results for different combinations of dazzle size and number of patches.
Fig 6.
Mean (±SD) percentage change in perceived speed for Experiment 5 (N = 15 participants).
All manipulations of the level of contrast in the texture produced a change in perceived speed that was significantly different from zero.
Table 4.
One-sample t-test results for differences between dynamic dazzle and static dazzle control for each of the 3 contrast levels tested.
Fig 7.
Colour combinations for Experiment 6.
Each combination was tested for the moving ‘with’ and moving ‘against’ directions, producing eight conditions.
Fig 8.
Mean perceived target speeds (± SD) for different colour combinations in Experiment 6 (N = 15 participants).
The effect of the texture was enhanced by the green background so that the perceived speed was increased for the moving with direction, and decreased for the moving against direction, when compared to the grey background.
Table 5.
Mean (±SD) for anxiety, mood, blood pressure and heart rate measures following inhalations of 7.5% CO2 and normal air.
Fig 9.
Mean (±SD) percentage change in perceived speed for the two inhalations conditions (N = 15 participants).
The dynamic texture causes the target to be perceived as moving faster or slower depending on the direction of the camouflage movement. This appears to be robust to stressful situations as the effect is similar for both normal air and 7.5% CO2 inhalations.