Table 3.
Descriptive Statistics by Age Group: Mean (SD)
| 10–11 | 12–13 | 14–15 | 16–17 | 18–21 | 22–25 | 26–30 | |
|---|---|---|---|---|---|---|---|
| Par. Ed. | 11.83 (3.00) | 12.07 (2.91) | 12.12 (2.78) | 11.86 (2.88) | 12.01 (2.79) | 11.78 (3.03) | 11.24 (3.24) |
| WASI | 48.33 (11.00) | 46.01 (11.07) | 46.18 (10.87) | 46.97 (10.54) | 49.81 (10.41) | 51.36 (10.19) | 51.42 (11.62) |
| RPI | .57 (.25) | .60 (.25) | .60 (.25) | .62 (.25) | .62 (.24) | .67 (.23) | .67 (.25) |
| Stoplight | .42 (.22) | .42 (.21) | .44 (.23) | .42 (.21) | .43 (.23) | .42 (.23) | .39 (.23) |
| DD | 400.85 (301.17) | 375.29 (303.76) | 384.49 (269.58) | 400.23 (295.09) | 415.20 (291.62) | 443.08 (303.11) | 437.20 (311.98) |
| IGT | −.02 (.24) | −.03 (.24) | −.06 (.25) | −.07 (.27) | −.10 (.28) | −.12 (.29) | −.13 (.32) |
| ToL | 4475.99 (3382.75) | 4467.41 (3661.45) | 5363.33 (5660.86) | 5848.01 (6092.83) | 6481.17 (5978.23) | 6926.48 (6618.99) | 7055.67 (6932.37) |
| WM | 6.11 (1.37) | 6.58 (1.26) | 6.97 (1.08) | 7.15 (1.00) | 7.26 (0.95) | 7.21 (1.08) | 7.17 (1.11) |
| VF | 10.5 (4.44) | 11.03 (5.15) | 12.72 (5.71) | 13.65 (6.52) | 13.94 (5.84) | 14.46 (6.49) | 14.90 (6.48) |
| DSB | 4.02 (1.19) | 4.26 (1.20) | 4.52 (1.47) | 4.61 (1.43) | 4.82 (1.49) | 4.81 (1.52) | 4.79 (1.39) |
| N | 1191 | 702 | 667 | 623 | 715 | 670 | 659 |
| % Female | 51.8 | 48.4 | 50.7 | 50.9 | 49.9 | 51.3 | 51.4 |
Note. Par. Ed. = Parental education. WASI = WASI t-score. DD = Delay discounting, average indifference point for longest delays. RPI = Resistance to peer influence (on a 0–1 scale). IGT = Iowa Gambling Task, corresponding to the proportion decrease in plays on disadvantageous decks. ToL = Tower of London, latency to first move (in ms). WM = Working memory, average accuracy (out of 8). VF = Verbal fluency, number of words produced in one minute. DSB = Digit Span backward, longest string of digits correctly recalled in reverse order (with a maximum value of 8).