#### 3.1. Behavioral Results

For the dependent variable of TT, the results of the three-way ANOVA revealed two-way interaction effects of Week and Level,

F (2, 52) = 14.71,

p ≤ 0.001, η

^{2} = 0.36, and Problem and Level,

F (2, 52) = 93.28,

p ≤ 0.001, η

^{2} = 0.78 (see

Figure 6). There were also main effects of Week,

F (1, 26) = 95.34,

p ≤ 0.001, η

^{2} = 0.79 and Level,

F (2, 52) = 289.81,

p ≤ 0.001, η

^{2} = 0.92.

Tukey HSD post hoc tests revealed that the total time spent on the tasks increased as the difficulty level increased both for Week 1 (M (mean) = −0.777, SD (standard deviation) = 0.496 for low, M = 0.604, SD = 0.912 for medium, M = 1.085, SD = 0.948 for high levels) and for Week 2 (M= −0.980, SD = 0.376 for low, M = −0.251; SD = 0.536 for medium, M = 0.320, SD = 0.581 for high levels) (see

Figure 7). Overall, the total time spent on both problems decreased from Week 1 (M = 0.304, SD = 1.130) to Week 2 (M = −0.303, SD = 0.733).

For the School Bus problem, it was found that the total time increased as the difficulty level increased (M = −0.649, SD = 0.286 for low, M = −0.297, SD = 0.763 for medium, M = 0.946, SD = 0.971 for high levels). For Ambulance problem, participants spent more time on medium (M = 0.650, SD = 0.673) than on low (M = −1.108, SD = 0.468) and high level tasks (M = 0.458, SD = 0.686). Overall, as the difficulty level increased, the total time spent on the tasks increased as well (M = −0.879, SD = 0.450 for low, M = 0.176, SD = 0.859 for medium, and M= 0.702, SD = 0.872 for high level tasks (see

Figure 7). A similar pattern is observed within each week for both the School Bus problem (M = −0.498, SD = 0.327 for low, M = 0.079, SD = 0.907 for medium, M = 1.395, SD = 1.025 for high level tasks in Week 1; M = −0.800, SD = 0.114 for low, M = −0.673, SD = 0.261 for medium, M = 0.498, SD = 0.672 for high level tasks in Week 2) and the Ambulance problem (M = −1.057, SD = 0.481 for low, M = 1.128, SD = 0.550 for medium, M = 0.775, SD = 0.762 for high level tasks in Week 1; M = −1.160, SD = 0.457 for low, M = 0.172, SD = 0.382 for medium, M = 0.141, SD = 0.412 for high level tasks in Week 2) (see

Figure 8).

For the dependent measure of RT, the results of the three-way ANOVA revealed a two-way interaction effect of Week and Level,

F (2, 52) = 12.19,

p ≤ 0.001, η

^{2} = 0.32. There were also main effects of Week,

F (1, 26) = 46.46,

p ≤ 0.001, η

^{2} = 0.64 and Level,

F (2, 52) = 30.42,

p ≤ 0.001, η

^{2} = 0.54. Tukey HSD post hoc tests revealed that the reaction time increased as the difficulty level increased both for Week 1 (M = −0.777, SD = 0.496 for low, M = 0.604, SD = 0.912 for medium, M = 1.085, SD = 0.948 for high level tasks) and Week 2 (M = −0.980, SD = 0.376 for low, M = −0.251, SD = 0.536 for medium, M = 0.320, SD = 0.581 for high level tasks) (see

Figure 9). It was also found that there was an overall decrease in reaction time from Week 1 (M = 0.304, SD = 1.130) to Week 2 (M = −0.304, SD = 0.733).

#### 3.2. fNIRS Results

For the dependent measure of LDLPFC OXY, the results of the three-way ANOVA revealed two-way interaction effects of Week and Level,

F (2, 52) = 6.92,

p ≤ 0.05, η

^{2} = 0.21, as well as Problem and Level,

F (2, 52) = 13.23,

p ≤ 0.001, η

^{2} = 0.34 (see

Figure 10). There were also main effects of Week,

F (1, 26) = 32.58,

p ≤ 0.001, η

^{2} = 0.56 and Level,

F (2, 52) = 4.23,

p ≤ 0.05, η

^{2} = 0.14.

Tukey HSD post hoc tests revealed that the average oxygenation for the LDLPFC region increased as the difficulty level of the tasks increased for Week 1 (M = −0.590, SD = 0.798 for low, M = −0.519, SD = 0.871 for medium, M = −0.318, SD = 0.955 for high level tasks). For Week 2, average oxygenation for medium level tasks was higher (M = 0.623, SD = 0.974) as compared to low (M = 0.401, SD = 0.838) and high (M = 0.404, SD = 0.811) level tasks. Overall, there was an increase in average oxygenation from Week 1 (M = −0.476, SD = 0.879) to Week 2 (M = 0.476, SD = 0.878). For the School Bus problem, it was found that average oxygenation for the LDLPFC region increased as the difficulty level increased (M = −0.222, SD = 0.894 for low, M = 0.043, SD = 1.126 for medium, M = 0.179, SD = 0.941 for high level tasks). For the Ambulance Problem, it was found that the average oxygenation level was highest for medium level tasks (M = 0.060, SD = 1.084), followed by low (M = 0.033, SD = 1.004) and high (M = −0.093, SD = 0.955) level tasks. Overall, oxygenation was highest for the medium level tasks (M = 0.052, SD = 1.084), followed by high (M = 0.043, SD = 0.954) and low level tasks (M = −0.094, SD = 0.955) (see

Figure 11). Similarly, an increasing pattern is observed from Week 1 to Week 2 within each level for each problem separately: the School Bus problem (M = −0.745, SD = 0.518 for low, M = −0.542, SD = 0.825 for medium, M = −0.294, SD = 0.776 for high level tasks for Week 1, M = 0.301, SD = 0.890 for low, M = 0.628, SD = 1.092 for medium, M = 0.653, SD = 0.860 for high level tasks for Week 2) and the Ambulance problem (M = −0.435, SD = 0.990 for low, M = −0.496, SD = 0.931 for medium, M = −0.342, SD = 1.121 for high level tasks for Week 1, M = 0.501, SD = 0.787 for low, M = 0.617, SD = 0.861 for medium, M = 0.155, SD = 0.688 for high level tasks for Week 2) (see

Figure 12).

For the dependent measure of RDLPFC OXY, the results of the three-way ANOVA revealed two-way interaction effects of Week and Level,

F (2, 52) = 7.18,

p ≤ 0.05, η

^{2} = 0.22, as well as Problem and Level,

F (2, 52) = 18.07,

p ≤ 0.00, η

^{2} = 0.41 (see

Figure 13). There were also main effects of Week,

F (1, 26) = 16.31,

p ≤ 0.001, η

^{2} = 0.39 and Level,

F (2, 52) = 4.05,

p ≤ 0.05, η

^{2} = 0.14.

Tukey HSD post hoc tests revealed that, for Week 1, average oxygenation for the RDLPFC region increased as the difficulty level of the tasks increased for Week 1 (M = −0.471, SD = 0.696 for low, M = −0.430, SD = 0.784 for medium, M = −0.220, SD = 0.901 for high level tasks). For Week 2, average oxygenation was higher for medium level tasks (M = 0.524, SD = 1.163), followed by high (M = 0.307, SD = 0.970) and low (M = 0.290, SD = 0.971) level tasks. Overall, there was an increase in average oxygenation from Week 1 (M = −0.374, SD = 0.801) to Week 2 (M = 0.374, SD = 1.038). For the School Bus problem, it was found that average oxygenation for the RDLPFC region increased as the difficulty level increased (M = −0.225, SD = 0.853 for low, M = 0.040, SD = 1.137 for medium, M = 0.184, SD = 0.964 for high level tasks). For the Ambulance Problem, it was found that the average oxygenation level was highest for medium tasks (M = 0.054, SD = 1.067), followed by low (M = 0.044, SD = 0.980) and high level tasks (M = −0.098, SD = 0.961). Overall, oxygenation was highest for the medium level tasks (M = 0.047, SD = 1.098), followed by high (M = 0.043, SD = 0.969) and low level tasks (M = −0.090, SD = 0.924) (see

Figure 14). Similarly, an increasing pattern is observed from Week 1 to Week 2 within each level for each problem separately: the School Bus problem (M = −0.602, SD = 0.551 for low, M = −0.471, SD = 0.660 for medium, M = −0.110, SD = 0.807 for high level tasks for Week 1, M = 0.153, SD = 0.940 for low, M = 0.556, SD = 1.287 for medium, M = 0.479, SD = 1.031 for high level tasks for Week 2) and the Ambulance problem (M = −0.341, SD = 0.806 for low, M = −0.388, SD = 0.902 for medium, M = −0.330, SD = 0.988 for high level tasks for Week 1, M = 0.428, SD = 1.000 for low, M = 0.497, SD = 1.050 for medium, M = 0.135, SD = 0.891 for high level tasks for Week 2) (see

Figure 15).

For the dependent measure of LANTPFC OXY, the results of the three-way ANOVA revealed two-way interaction effects of Week and Level,

F (2, 52) = 5.27,

p ≤ 0.05, η

^{2} = 0.17 (

Figure 16), as well as Problem and Level,

F (2, 52) = 15.52,

p ≤ 0.001, η

^{2} = 0.37 (see

Figure 13). There were also main effects of Week,

F (1, 26) = 29.62,

p ≤ 0.001, η

^{2} = 0.53 and Level,

F (2, 52) = 3.75,

p ≤ 0.05, η

^{2} = 0.13.

Tukey HSD post hoc tests revealed that, for Week 1, average oxygenation for the LANTPFC region increased as the difficulty level of the tasks increased for Week 1 (M = −0.477, SD = 0.737 for low, M = −0.460, SD = 0.715 for medium, M = −0.272, SD = 0.896 for high level tasks). For Week 2, the average oxygenation was higher for medium level tasks (M = 0.581, SD = 1.161), followed by high (M = 0.320, SD = 0.972) and low (M = 0.309, SD = 0.927) level tasks. Overall, there was an increase in average oxygenation from Week 1 (M = −0.403, SD = 0.787) to Week 2 (M = 0.403, SD = 1.026). For the School Bus problem, it was found that average oxygenation for the LANTPFC region increased as the difficulty level increased (M = −0.236, SD = 0.864 for low, M = 0.054, SD = 1.126 for medium, M = 0.182, SD = 0.964 for high level tasks). For the Ambulance Problem, it was found that the average oxygenation level was highest for low level tasks (M = 0.068, SD = 0.960), followed by medium (M = 0.066, SD = 1.069) and high level tasks (M = −0.134, SD = 0.973). Overall, oxygenation was highest for the medium level tasks (M = 0.060, SD = 1.093), followed by high (M = 0.024, SD = 0.977) and low (M = −0.084, SD = 0.922) level tasks (see

Figure 17). Similarly, an increasing pattern is observed from Week 1 to Week 2 within each level for each problem separately: the School Bus problem (M = −0.661, SD = 0.554 for low, M = −0.469 SD = 0.664 for medium, M = −0.169, SD = 0.773 for high level tasks for Week 1, M = 0.189, SD = 0.917 for low, M = 0.578, SD = 1.255 for medium, M = 0.533, SD = 1.020 for high level tasks for Week 2) and the Ambulance problem (M = −0.292, SD = 0.854 for low, M = −0.452, SD = 0.775 for medium, M = −0.375, SD = 1.008 for high level tasks for Week 1, M = 0.429, SD = 0.938 for low, M = 0.583, SD = 1.082 for medium, M = 0.108, SD = 0.890 for high level tasks for Week 2) (see

Figure 18).

For the dependent measure of RANTPFC OXY, the results of the three-way ANOVA revealed two-way interaction effects of Week and Level,

F (2, 52) = 7.47,

p ≤ 0.00, η

^{2} = 0.22, as well as Problem and Level,

F (2, 52) = 15.42,

p ≤ 0.001, η

^{2} = 0.37 (see

Figure 19). There was also a main effect of Week,

F (1, 26) = 25.92,

p ≤ 0.001, η

^{2} = 0.50.

Tukey HSD post hoc tests revealed that, for Week 1, average oxygenation for the RANTPFC region increased as the difficulty level of the tasks increased for Week 1 (M =−0.468, SD =0.697 for low, M = −0.493, SD = 0.660 for medium, M = −0.281, SD = 0.857 for high level tasks). For Week 2, average oxygenation was higher for medium level tasks (M = 0.587, SD = 1.161), followed by low (M = 0.333, SD = 0.922) and high (M = 0.322, SD = 1.016) level tasks. Overall, there was an increase in average oxygenation from Week 1 (M = −0.414, SD = 0.745) to Week 2 (M = 0.414, SD = 1.049). For the School Bus problem, it was found that average oxygenation for the RANTPFC region increased as the difficulty level increased (M = −0.214, SD = 0.857 for low, M = 0.046, SD = 1.112 for medium, M = 0.169, SD = 0.995 for high level tasks). For the Ambulance problem, it was found that the average oxygenation level was highest for low level tasks (M = 0.079, SD = 0.941), followed by medium (M = 0.048, SD = 1.099) and high level tasks (M = −0.127, SD = 0.958) (see

Figure 20). Similarly, an increasing pattern is observed from Week 1 to Week 2 within each level for each problem separately: the School Bus problem (M = −0.644, SD = 0.493 for low, M = −0.511, SD = 0.491 for medium, M = −0.197, SD = 0.708 for high level tasks for Week 1, M = 0.215, SD = 0.933 for low, M = 0.603, SD = 1.279 for medium, M = 0.534, SD = 1.112 for high level tasks for Week 2) and the Ambulance problem (M = −0.292, SD = 0.827 for low, M = −0.474, SD = 0.803 for medium, M = −0.365, SD = 0.991 for high level tasks for Week 1, M = 0.450, SD = 0.914 for low, M = 0.571, SD =1.118 for medium, M = 0.110, SD = 0.879 for high level tasks for Week 2) (see

Figure 21).