## 5 Measurement and Parameters Selection
### Behavioural Measurements  
Among the selected studies, behavioral data analyses provide complementary information to questionnaires, useful in validating initial hypotheses. Among the numerous behavioral parameters, those related to participants' performance in the MR environment are common. One key parameter is latency time, defined as the period between a stimulus and the participant's behavioral response. This metric offers insights into the speed and effectiveness of user reactions in the virtual environment. A short latency time may indicate high embodiment with prompt responses, while a longer time may suggest more cognitive processing or uncertainty, reflecting lower embodiment. Similarly, the transversal time corresponds to an additional behavioural parameter correlated with embodiment [57]. This parameter was defined as the duration required to complete a specific task or action within the virtual environment. Measuring the transversal time may allow for evaluating the efficiency and competence of users in performing assigned activities, providing valuable insights into their familiarity with the virtual environment and their navigational skills. The discomfort response time was another particularly relevant behavioural parameter selected by the most recent approaches for evaluating embodiment in MR [57; 27]. Such a parameter was calculated by observing when the participant responded to a stressful stimulus, i.e., the approach of an avatar in virtual reality, in order to evaluate the participant reaction to stress or discomfort within the MR environment. Finally, another crucial behavioural parameter emerging by the recent scientific literature is the walking time. Indeed, such a parameter was strictly associated with the experimental protocol, including consistent spatial navigation activities requested to the participants [31; 57]. The following Table 3 provides an overview about the behavioural parameters that emerged from the considered scientific literature:  
\begin{table}
\begin{tabular}{l l l l} \hline
**Questionnaire** & **Year** & **Items** & **Experiments** \\ \hline Questionnaire on Presence and Realism (QPR) & 1998 & 10 & 1 \\ [PERSON] et al. Questionnaire & 1999 & 14 & 2 \\ [PERSON] et al. Questionnaire & 2000 & 5 & 2 \\ [PERSON] et al. Questionnaire & 2000 & 9 & 1 \\ Reality Judgment and Presence Questionnaire (RJPQ) & 2000 & 18 & 1 \\ Lombard \& Ditton Questionnaire & 2000 & 103 & 1 \\ [PERSON] et al. Questionnaire & 2001 & 19 & 2 \\ Igroup Presence Questionnaire (IPQ) & 2001 & 14 & 3 \\ Swedish Viewer-User Presence (SVUP) & 2001 & 150 & 1 \\ ITC Sense of Presence Inventory (ITC-SOPI) & 2001 & 63 & 1 \\ [PERSON] et al. Questionnaire & 2001 & 42 & 1 \\ Swedish User-Viewer Presence Questionnaire & 2001 & 19 & 3 \\ [PERSON] et al. Questionnaire & 2001 & 10 & 2 \\ Experimental Virtual Environment-Experience (EVEQ) & 2002 & 124 & 1 \\ E\({}^{2}\)I Scale Development & 2002 & 9 & 2 \\ [PERSON] et al. Questionnaire & 2003 & 4 & 3 \\ Nowak and Biocca Questionnaire & 2003 & 29 & 1 \\ Sas and O’Hare Questionnaire & 2003 & 34 & 1 \\ MEC Spatial Presence Questionnaire (MEC-SPQ) & 2004 & 16 & 1 \\ [PERSON] et al. Questionnaire & 2004 & 1 & 1 \\ Presence-Involvement-Flow Framework (PIFF) & 2004 & 15 & 1 \\ Template Presence Inventory (TPI) & 2009 & 42 & 1 \\ Virtual Experience Test (PET) & 2010 & 24 & 1 \\ Spatial Presence (P) and Self-presence (SP) & 2016 & 5 & 3 \\ Embodiment Questionnaire (EQ) & 2020 & 10 & 1 \\ \hline \end{tabular}
\end{table}
Table 2: _Cont._