TABLE 3.
Average WMC and verbal comprehension scores depending on visual ability.
| Sample | Blind | Visually impaired | Sighted | r [95% CI] | Cohen’s d [95% CI] |
| M (SD) | M (SD) | M (SD) | |||
| South Africa (N = 155) | |||||
| WMC | 120.47 (10.47) | 110.43 (12.94) | 103.21 (10.14) | +0.52 [+0.39, +0.63] | +1.67 [+1.42, +1.93] |
| VC | 80.16 (10.82) | 78.53 (11.71) | 92.06 (8.68) | −0.40 [−0.52, −0.26] | −1.22 [−1.45, −0.97] |
| Austria (N = 94) | |||||
| WMC | 114.00 (21.35) | 102.58 (17.29) | 106.77 (14.10) | +0.11 [−0.09, +0.31] | +0.40 [+0.17, +0.62] |
| VC | 89.63 (9.44) | 90.29 (13.55) | 99.50 (12.69) | −0.33 [−0.49, −0.13] | −0.89 [−1.12, −0.65] |
| All together (N = 249) | |||||
| WMC | 118.55 (14.69) | 107.70 (14.98) | 104.84 (12.18) | +0.35 [+0.24, +0.45] | +1.02 [+0.78, +1.25] |
| VC | 82.97 (11.24) | 82.63 (13.53) | 95.47 (11.28) | −0.39 [−0.49, −0.28] | −1.11 [−1.35, −0.87] |
WMC, working-memory capacity; VC, verbal comprehension; r, correlation between visual ability (sighted: “0,” visually impaired: “1,” blind: “2”) and ability results in the respective IQ dimension; d = intelligence difference between the blind and sighted expressed in standard deviation units (M = 0, SD = 1) using the averaged standard deviations of the blind and sighted of this sample (not SD = 15), positive values mean higher results for the blind.