## 4 Results
### Variance in Learning Outcomes  
To further explore the varying effect of debriefing on different types of knowledge and behavioral learning outcomes, independent sample \(t\)-tests were performed on the posttest sub-scores of both treatment and control groups. The group differences are plotted in Figure 5.  
\begin{table}
\begin{tabular}{l c c c c c c c} \hline \multirow{2}{*}{**Variable**} & \multirow{2}{*}{**Trials a**} & \multicolumn{3}{c}{**Within-Subjects Effects**} & \multicolumn{3}{c}{**Trial \(\times\) Debriefing**} \\ \cline{3-8}  & & \(F\) & \(p\) & \({\eta_{p}}^{2}\) & \(F\) & \(p\) & \({\eta_{p}}^{2}\) \\ \hline \multirow{2}{*}{Knowledge test scores} & pretest: 5.840 (2.510) & \multirow{2}{*}{32.640} & \multirow{2}{*}{0.000} & \multirow{2}{*}{0.309 **} & \multirow{2}{*}{2.068} & \multirow{2}{*}{0.155} & \multirow{2}{*}{0.028} \\  & posttest: 7.220 (2.377) & & & & & & \\ \hline \multirow{2}{*}{Behavior assessment scores} & pretest: 0.412 (0.171) & \multirow{2}{*}{57.612} & \multirow{2}{*}{0.000} & \multirow{2}{*}{0.434 **} & \multirow{2}{*}{7.627} & \multirow{2}{*}{0.007} & \multirow{2}{*}{0.092 **} \\  & posttest: 0.536 (0.211) & & & & & & \\ \hline \end{tabular}
\end{table}
Table 1: Within-subjects effects of the trials and the interaction with debriefing (N = 77).  
Figure 4: Comparison of the two groups of knowledge and behavior pretest and posttest scores. (**a**) improvement of knowledge test scores, (**b**) improvement of behavior assessment scores.  
In terms of knowledge acquisition, Figure 5a shows that the treatment group showed significantly higher scores in both the interpretation and decision-making sections of the knowledge test (MD\({}_{\text{(interpretation)}}\) = 0.7, SD = 0.24, \(p\) = 0.005; MD\({}_{\text{(decision\,making)}}\) = 1.27, SD = 0.33, \(p\) = 0.000), in comparison with the control group. Further, the effect size of the mean difference in decision-making scores was considered large ([PERSON]'s \(d\) = 0.87), while the effect size in interpretation scores was medium ([PERSON]'s \(d\) = 0.66). The statistical results suggest that, despite its general effectiveness in promoting the participants' knowledge acquisition, the impact of debriefing on participants' decision making tended to be greater than that on interpretation.  
In terms of behavioral performance, the treatment group received significantly higher behavior scores than the control group in two of the three challenges in the IVR environment, as seen in Figure 5b. The effect sizes of the mean differences for Challenge 1 and 3 were 0.72 and 0.63, respectively, which is considered a medium effect. The results indicated that, after participating in the debriefing session, the participants demonstrated improved pedestrian behaviors in two street-crossing risk scenarios themed by peer influence (C1) and backing vehicles (C3). Interestingly, despite the medium effect size of mean difference (MD = 0.157, \(d\) = 0.41), the discrepancy between the treatment and control group in Challenge 2 performance was statistically insignificant (\(p\) = 0.079). A plausible explanation is that the theme of a blinking traffic light in Challenge 2 was deemed more difficult by the participants, leading to greater standard deviation in the behavior scores of Challenge 2 (SD = 0.088) that that of the other two challenges (SD = 0.057, SD = 0.043). This result suggests that the difficulty of learning tasks merits our attention when examining the effectiveness of debriefing on IVR learning.