# Visual and Haptic Guidance for Enhancing Target Search Performance in Dual-Task Settings
## 1 Introduction  
In complex everyday environments, users often find themselves managing multiple tasks simultaneously. For example, in traffic scenarios, pedestrians, cyclists, and drivers navigating a bustling cityscape must stay aware of their immediate surroundings while also being vigilant of potential hazards from behind. This multitasking demand extends to industrial contexts, where workers operating heavy machinery need to manage controls while maintaining situational awareness to avoid accidents. The complexity of such scenarios intensifies in critical professional settings such as firefighting, where individuals must stay alert to their surrounding environment while advancing toward a fire. In these environments, guiding users' attention to improve multitasking performance is crucial for safety. A considerable body of research exists that provides diverse strategies for improving user performance. For instance, the role of attention cues and information awareness on visual displays, such as Head-Mounted Displays (HMDs) or mobile screens, has been extensively explored across various fields, including the medical [1], industrial [2], and tourism sectors [3]. Numerous visual guidance designs have been investigated to help users, such as arrows [2, 4, 5], halos [6], attention funnels [7], and wedges [8]. In addition to visual guidance, other modalities, such as haptic feedback, have been extensively applied in various user scenarios, including digital gaming [9], stress relief [10], and traffic navigation [11, 12]. Haptic feedback can deliver realistic and immersive user experiences with wearable devices [13, 14, 15, 16] and provide guidance or warning signals through wearable devices like belts and vests [17], enhancing traffic awareness and directional sense. In scenarios like traffic or industry, where users need to stay aware of their environment and actively search for targets, users' perception and cognitive load are intenselydemanded [18]. The Multiple Resource Theory suggests that dual tasks drawing upon the same sensory modality could potentially interfere with each other more than tasks requiring different resources [19]. Thus, employing multiple modalities (e.g., visual and haptic feedback) can be advantageous in complex dual-task settings. Experimental evidence supports that multimodal interaction can improve users' perception of surroundings and operation accuracy [20]. In dual-task settings, haptic feedback has proven to be a valuable interaction modality, shown to enhance user performance. For instance, haptic displays can increase situational awareness without affecting the primary task in traffic environments [21]. Haptics may also help maintain visual attention on the road, while allowing for reliable dashboard control in driving scenarios [22]. Experiments have also showed that vibrotactile displays can effectively guide users to targets without impacting their performance on other concurrent tasks [23]. Augmented visual signs and haptic input modalities are well-known interface designs; however, their effectiveness in enhancing target search performance in dual-task settings still needs further investigation. Given the complexities and challenges of managing multiple tasks in dynamic user scenarios, the research objective of this paper was to investigate the potential of visual and haptic guidance in enhancing the target search performance within dual-task settings. We address the challenge of efficiently guiding users' attention in environments where multiple tasks must be managed. Through two user studies, we explored the efficacy of visual and haptic feedback to understand their impact on user responsiveness and preference. In both studies, participants engaged in a primary task of searching for and selecting a target within a \(5\times 5\) grid in front of them, and they were guided to a secondary task of searching for and selecting a target within a \(2\times 5\) grid behind them.