The five different number of bars are represented by different symbols; 6(▪), 24(♦), 48(▴), 72(*) and 96 (○). The two luminance conditions (congruent and incongruent) are represented by dotted or continuous lines. A shows effects of complexity (F1,7= 16.992, P < 0.01), colour (trichrome > monochrome, F1,966= 13.024, P < 0.001) and luminance (congruent > incongruent, F1,966= 8.771, P < 0.01) on the perceived depth.