# Movement Time for Pointing Tasks in Real and Augmented Reality Environments
## 4 Discussion  
### Movement Time of Pointing Tasks on Physical and Virtual Targets  
Pointing tasks are required when users are using their fingertips to touch a target. Pointing on a physical key and on a virtual one were quite different. For the physical pointing, the control of hand movement was intuitive. When the fingertip touched the target, it was stopped by a board. There was strong tactile feedback. The literature [50] has shown that mechanical interactions of the hand and an object could interfere with the trajectory of the hand and thus affect the MT. For the virtual pointing, the participant needed to move his/her fingertip to the exact location of the target, both in the 2D plane of the virtual panel and in the axis perpendicular to the panel. There was no tactile feedback. Both a visual (the ring became a solid circle) and an auditory signal were presented when a \"touch\" was successful. However, the feedback, especially the visual one, was not as prominent as that of the tactile one. The fingertip might move over and \"penetrate\" the virtual panel, as there was no solid to stop it. It was also possible that there may be errors between the visual location of the virtual panel and actual location as recognized by the app in the AR glass [51]. The participant, therefore, needed to make fine adjustments following the cue of visual feedback of the fingertip location in the axis perpendicular to the panel until he or she received visual feedback of a successful input. Such a fine adjustment significantly increased the time for the pointing tasks on the virtual panel.  
The regression coefficient \(d\) in Table 3 indicates the average extra amount of MT (755-1026 ms) required because the panel was a virtual one. The ratios of MT using the virtual panel versus the one using the physical panel may be calculated using our MT data. It was found that the participants needed to spend 2.23-2.79-fold more time on the MT, on average, to complete the pointing task on the virtual panel than on the physical panel under our experimental conditions. These numbers indicated the effects of the factor \(T\) and the inefficiency of using a virtual panel for data input. These results were consistent with  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Gender** & **Hand** & \(c^{\prime}\) & \(d^{\prime}\) & **1/b (bit/s)** \\ \hline Horizontal & Movement & & & \\ Female & D & 0.88 & \(-\)7.22 & 7.4 \\ Female & ND & 0.76 & \(-\)7.12 & 6.9 \\ Male & D & 1.61 & \(-\)5.98 & 7.1 \\ Male & ND & 1.52 & \(-\)6.35 & 7 \\ Vertical & Movement & & & \\ Female & D & 1.02 & \(-\)12.81 & 15 \\ Female & ND & 1.15 & \(-\)12.19 & 13.4 \\ Male & D & 2.13 & \(-\)12.03 & 15.9 \\ Male & ND & 2.13 & \(-\)11.88 & 14.8 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Coefficients of ID\({}_{\text{adj}}\) and \(1/b\).  
the findings in the literature that pointing virtual objects required more time than pointing physical ones [45].  
The results of this study support the hypothesis that the MT of pointing tasks on the virtual targets in an AR environment is longer than that on physical targets. This was consistent with the findings in the literature [48]. In addition, the hypotheses that the MT of the pointing tasks was affected by the gender and handedness of the participants were also supported.