“…From the results shown in Table 2 , we can infer that arousal, dominance, MAF, SCR frequency, HR, and SCL changed significantly across the four difficulty levels (i.e., p < 0.05). These results are coherent with previous studies on psychophysiological changes during mixed physical/psychological HRI tasks (Rodriguez Guerrero et al, 2010 ; Novak et al, 2010a , b , 2011a , b ; Koenig et al, 2011a , c ; Badesa et al, 2012 , 2014 ; Morales et al, 2014 ) and show that, in this experiment, HR, SCL, and SCR were the most sensitive physiological parameters to discriminate between the difficulty levels of the VR task. For HR, the observations made went further and showed that this variable exhibited a considerable inertia when preceded by a higher level of physical activity, as can be seen in Figure 5 (i.e., delayed effect of task presentation order, see Table 1 ; more specifically, a continued effect of level 4 on level 2 can be seen).…”