Table 1. Mean ± SD of JNDs for chromatic and luminance (achromatic) contrasts.
To determine whether T-shirts differed in their resemblance to the sexually-selected blue patches of male Sceloporus occidentalis, we calculated JNDs by comparing T-shirts to the throat patch and to the abdominal patch of lizards. To determine whether T-shirts differed in their detectability, we calculated JNDs by comparing T-shirts to the background environment from photographs taken within each study site.
| Contrast type | Comparison region | T-shirt color | |||
|---|---|---|---|---|---|
| Dark blue | Light blue | Gray | Red | ||
| Chromatic | Throat | 3.0 ± 1.5 | 2.3 ± 1.0 | 3.4 ± 1.8 | 8.2 ± 1.7 |
| Abdomen | 7.2 ± 1.2 | 7.2 ± 1.3 | 7.6 ± 1.5 | 9.8 ± 1.1 | |
| Background environment | 10.3 ± 3.4 | 6.9 ± 3.2 | 3.6 ± 1.0 | 59.2 ± 6.4 | |
| Luminance | Throat | 1.4 ± 1.2 | 3.6 ± 1.7 | 7.5 ± 1.7 | 5.1 ± 1.7 |
| Abdomen | 5.2 ± 2.4 | 2.0 ± 1.0 | 11.7 ± 2.4 | 9.3 ± 2.4 | |
| Background environment | 7.6 ± 6.8 | 16.6 ± 10.5 | 13.9 ± 8.1 | 8.2 ± 7.1 | |