# Visual and Haptic Guidance for Enhancing Target Search Performance in Dual-Task Settings
## 5 Discussion
### Effect of Target Position  
In the primary task, without any guidance for target selection, participants were required to independently select targets from a densely populated environment. As a result, their active search strategy usually began from the central area. Consequently, targets situated in the middle columns (i.e., columns 2, 3, and 4) were selected faster than those in the peripheral columns (i.e., columns 1 and 5). This pattern remained consistent in both Study 1 and Study 2. With regard to the various rows in the primary task, targets located in the middle rows were also selected more quickly than those at the top and bottom, suggesting that users tend to initiate their search from the center before expanding vertically.  
Consistent with the selection time, head movements (i.e., the angle of head rotation and the distance of head movement) were shorter when users selected targets in the central area. These findings are in accordance with previous research on freehand selection, which found that users tend to position their hands and focus their vision around the center area when selecting a target in a grid-option layout [66].  
In the Secondary Task, targets were located behind the user, and directional guidance was provided via visual and haptic feedback. This setup required users to turn either left or right following the guidance, making them aware of the potential target's location behind them. Consequently, the Secondary Task fostered a distinct target search strategy compared to the Primary Task; users would initiate their search for the target from the sides and then move toward the center. As a result, targets in the columns on either side of the target area behind (i.e., columns 1 and 2 vs. 4 and 5) were identified faster than those in column 3 in the middle. Correspondingly, the middle column was also associated with larger head rotation angles and greater distances of head movement. The comparison of selection times and rotation angles for targets located in the side and center columns during the Primary and Secondary Tasks in Study 2 are summarized in Table 4.  
\begin{table}
\begin{tabular}{c c c c c} \hline \hline  & \multicolumn{2}{c}{**Primary Task**} & \multicolumn{2}{c}{**Secondary Task**} \\  & **Selection** & **Head Rotation** & **Selection** & **Head Rotation** \\  & **Time (s)** & **Angle (\({}^{\circ}\))** & **Time (s)** & **Angle (\({}^{\circ}\))** \\ \hline Columns 1 & 3.01 & 79.92 & 3.12 & 133.85 \\ Columns 3 & 2.59 & 67.79 & 4.11 & 193.91 \\ Columns 5 & 3.06 & 82.95 & 3.25 & 139.82 \\ \hline \hline \end{tabular}
\end{table}
Table 4: Comparison of mean selection times and head rotation angles for targets in side and center columns during Primary and Secondary Tasks in Study 2.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline  & **Visual Feedback** &
\begin{tabular}{c} **Visual–Haptic** \\ **Feedback** \\ \end{tabular} & **Improvement (\%)** \\ \hline Reaction Time & 5.24 s & 3.86 s & 26.34\% \\ User Preference & 4.25 & 7.75 & 82.35\% \\ Task load & 34.31 & 23.89 & 30.37\% \\ \hline \hline \end{tabular}
\end{table}
Table 3: Comparison of visual feedback and visual–haptic feedback for Secondary Task in Study 2.