Table 3.
Parameter estimates with confidence intervals for the 4-parameter logistic models of behavioral, self-report, and physiological correlates of alertness and executive functioning and goodness of fit based on data of the morning sessions.
| Variable | a | b | c | d | R 2 | |
|---|---|---|---|---|---|---|
| Behavioral indicators | PVT | −0.51 (−0.72, −0.31) | 1.91 (−495, −498) | 270 (−9.83 × 107, 9.83 × 107) | −0.40 (−0.52, −0.28) | 0.02 |
| Go-NoGo task, speed | 0.06 (−0.76, 0.88) | 1.52 (−18.81, 21.85) | 158 (−2.22 × 105, 2.23 × 105) | −0.61 (−0.81, −0.41) | 0.07 | |
| Go-NoGo task, accuracy | 0.14 (−1.14 × 105, 1.14 × 105) | 0.57 (−1.23 × 106, 1.23 × 106) | 0.05 (−3.82 × 104, 3.82 × 104) | −0.12 (−1.01 × 105, 1.01 × 105) | <0.01 | |
| 2-Back task, speed | 0.03 (−0.24, 0.29) | 1.96 (−0.20, 4.12) | 5.36 (−29.55, 40.28) | −0.06 (−0.21, 0.09) | 0.05 | |
| 2-Back task, accuracy | −0.25 (−3316, 3316) | 1.24 (−1.73 × 104, 1.73 × 104) | 0.21 (−2676, 2677) | 0.21 (−2671, 2671) | <0.01 | |
| Subjective indicators | Sleepiness | 0.96 (0.36, 1.56) | 2.38 (−1955, 1960) | 409 (−1.56 × 109, 1.56 × 109) | 0.24 (−0.39, 0.88) | 0.05 |
| Vitality | −0.43 (−0.67, −0.18) | 2.36 (−1.57, 6.29) | 174 (−3.38 × 104, 3.41 × 104) | −0.13 (−0.37, 0.10) | 0.05 | |
| Physiological indicators | HR | 0.53 (−2.81, 3.86) | 1.65 (−1.35, 4.65) | 171 (−1.34 × 104, 1.38 × 104) | −1.82 (−2.99, −0.65) | 0.04 |
| SCL | 0.94 (−0.12, 2.00) | 3.11 (−1040, 1046) | 475 (−5.14 × 107, 5.14 × 107) | 5.31 (1.06, 9.56) | 0.13 |
PVT = Psychomotor Vigilance Task; HR = heart rate; SCL = skin conductance level. All values correspond to difference scores compared with baseline. Parameters b and c are printed in bold if significantly different from 0; parameters a and d are printed in bold if their 95% confidence intervals do not overlap.