Table 1.
A comparison of Mensa and control samples in terms of chronotype-related and miscellaneous variables.
| N (Control) | N (Mensa) | M (Control) | M (Mensa) | SD (Control) | SD (Mensa) | Cohen’s d | p | ||
|---|---|---|---|---|---|---|---|---|---|
| Work day | Age (years) | 586 | 569 | 38.17 | 38.22 | 10.66 | 10.74 | <0.01 | 0.94 |
| Bedtime (hmidnight) | 577 | 518 | −0.69 | −0.65 | 1.39 | 1.28 | −0.03 | 0.67 | |
| Sleep preparation (hmidnight) | 577 | 518 | −0.56 | −0.31 | 1.21 | 1.28 | −0.20 | <0.001 | |
| Sleep latency (min) | 576 | 517 | 16.99 | 13.36 | 16.92 | 15.32 | 0.22 | <0.001 | |
| Sleep onset (hmidnight) | 577 | 517 | −0.27 | −0.09 | 1.25 | 1.32 | −0.14 | 0.02 | |
| Wake time (hmidnight) | 578 | 516 | 6.69 | 6.91 | 1.21 | 1.31 | −0.17 | <0.001 | |
| Waking inertia (min) | 574 | 517 | 15.98 | 15.41 | 16.54 | 17.08 | 0.03 | 0.57 | |
| Sleep duration (h) | 577 | 518 | 6.98 | 6.99 | 1.07 | 1.07 | −0.01 | 0.89 | |
| Midsleep (hmidnight) | 576 | 517 | 3.21 | 3.40 | 1.10 | 1.22 | −0.17 | 0.01 | |
| Free day | Bedtime (hmidnight) | 585 | 518 | 0.44 | 0.28 | 1.74 | 1.44 | 0.10 | 0.11 |
| Sleep preparation (hmidnight) | 585 | 518 | 0.54 | 0.58 | 1.66 | 1.44 | −0.02 | 0.69 | |
| Sleep latency (min) | 580 | 517 | 13.92 | 11.61 | 14.53 | 13.17 | 0.17 | 0.01 | |
| Sleep onset (hmidnight) | 574 | 517 | 0.71 | 0.76 | 1.51 | 1.48 | −0.04 | 0.56 | |
| Wake time (hmidnight) | 570 | 515 | 8.67 | 8.75 | 1.71 | 1.72 | −0.04 | 0.48 | |
| Waking inertia (min) | 578 | 512 | 19.40 | 24.19 | 18.87 | 22.58 | −0.23 | <0.001 | |
| Sleep duration (h) | 571 | 518 | 8.03 | 7.98 | 1.48 | 1.32 | 0.03 | 0.59 | |
| Midsleep (hmidnight) | 573 | 518 | 4.77 | 4.77 | 1.63 | 1.51 | 0.02 | 0.94 | |
| Chronotype (corrected midsleep, hmidnight) | 551 | 485 | 4.30 | 4.32 | 1.39 | 1.37 | −0.02 | 0.75 | |
| Light exposure (work day, h) | 571 | 516 | 2.54 | 1.12 | 1.93 | 0.97 | 0.92 | <0.001 | |
| Light exposure (free day, h) | 574 | 517 | 3.37 | 2.06 | 1.86 | 1.31 | 0.81 | <0.001 | |
| Social jetlag (h) | 551 | 485 | 1.58 | 1.39 | 1.06 | 0.97 | 0.19 | <0.001 | |
| Social jetlag (h), corrected for oversleeping | 552 | 485 | 1.23 | 1.14 | 0.87 | 0.79 | 0.11 | 0.08 | |
| Sleep deprivation/week (h) | 552 | 484 | 1.97 | 1.61 | 1.85 | 1.52 | 0.21 | <0.001 | |
| Workdays/week | 564 | 485 | 4.92 | 5.16 | 0.77 | 0.75 | −0.31 | <0.001 | |
Statistical significance is derived from independent sample t-tests. Bold p-values indicate differences which were significant after correcting for multiple comparisons. Effect sizes are reported in Cohen’s d, and positive signs correspond to higher values in controls. hmidnight indicates that the value is a time point expressed in fractions of hours before (negative) or after (positive) midnight. Chronotype refers to free day midsleep corrected for oversleeping.