"Butt call me once you get a chance to chat 🙂" : Designing Persuasive Reminders for Veterans to Facilitate Peer-Mentor Support

US military veterans (USMVs) are a vulnerable population with an elevated risk of mental health issues and suicide. Peer support, especially through mobile technology, has proven effective in addressing mental health related challenges, but ensuring long-term engagement remains a concern. This study explores the opportunity of designing persuasive technology, particularly persuasive reminders, to enhance engagement in peer support interventions for veterans. We followed community-based participatory research with ten veterans to identify specific peer support processes that can benefit from persuasive reminders and to uncover the underlying community values and needs to guide design. The findings emphasize the importance of designing reminders that focus on personalized strategies, effective delivery of success stories, understanding motivation levels, careful language selection, actionable reminders, and mutual accountability. The study advocates context-specific design and highlights the need for a broader user-centered persuasion design perspective to cater to veterans’ unique needs.


INTRODUCTION
US military veterans (USMVs) face an increased risk of encountering mental health (MH) concerns [23].Approximately one in every fve veterans experiences MH related concerns, which can encompass a spectrum of conditions such as post-traumatic stress disorder (PTSD), major depression, and anxiety disorders [39].They are recognized as a high-risk group for suicide, and between 2005 and 2015, the age-adjusted suicide rates increased more signifcantly among veterans (32.7%) compared to non-veterans (19.9%) [16].Moreovers, USMVs face signifcant challenges reintegrating into civilian life due to the trauma they have experienced during their service, and the reintegration process presents multifaceted risks, including difculties in accessing healthcare, securing employment, maintaining fnancial stability, and ensuring housing security, among other concerns [22].However, due to issues like accessibility, stigma, and cost, many veterans struggle to access the support they need [29].Supplementing traditional treatment with peer support has proven efective in reducing various treatment-related challenges in veterans [17,29,35].In 2004, the Veterans Administration (VA) MH Strategic Plan emphasized the formalization of peer support within the VA by hiring veterans as Peer/MH Para-professionals commonly known as "peer mentors" [11,47].A peer mentor, typically a veteran who has successfully navigated the re-adjustment phase, can be invaluable to veterans dealing with MH conditions.Developing systematic approaches to enhance mentor-mentee communication quality holds promise in this regard.
Peer support through mobile technologies make it convenient for veterans to share their experiences comfortably [26].However, ensuring commitment to treatment and ongoing engagement with these mobile therapies is crucial [77].Adherence rates among patients using mobile MH apps have been suboptimal, and therefore, strategies to enhance user engagement are called for [29].One promising approach involves the creation of persuasive technology that incorporates design and technological components to efectively inspire and involve users, thereby enhancing the efectiveness and utility of mobile MH applications [57].An exploration of a persuasive approach that combines technology with human assistance to facilitate lasting behavioral changes in a fexible and efcient manner can be efective.
Among diferent principles of persuasive technology, persuasive reminders, which leverage social support, have proven efective in enhancing motivation, ability, and triggers to drive behavior change [42].They align task timing with motivation and capability, going beyond traditional reminders [36,45,57].In the domain of MH, especially for USMVs, persuasive reminders can play a crucial role in promoting mental well-being outside of clinical settings.US-MVs, as a demographic, present distinct challenges in technology integration due to their susceptibility to crises.It is crucial to thoroughly investigate technology interventions in the veteran context, particularly for those with mental health concerns, before implementation.Therefore, in this study, we aim to develop persuasive reminders within mobile MH apps to facilitate peer support interventions, addressing the unique needs of USMVs by frst addressing the following two research questions.
RQ1: What domains/areas should persuasive reminders be strategically implemented within, to improve the peer-mentor MH support systems for USMVs?RQ2: What are the underlying values and needs for creating effective persuasive reminders within peer-mentor support systems for USMVs?
To answer these questions, we conducted three focus groups and two participatory design workshops involving ten U.S. military veterans currently serving as mentors in a peer mentor-mentee intervention.Our research uncovered specifc nuances in communication with veterans that have important implications for designing persuasive reminders.Our fndings highlighted strategic design of persuasive reminders that motivate mentors to increase communication, particularly through check-ins, and focus on alerting mentees about potential crisis symptoms and available well-being resources.Furthermore, our fndings have challenged traditional concepts related to the implementation of persuasive reminders, with a few notable observations, such as, using names to address often undermine trust in sensitive contexts, gentle and non-aggressive tone used for gentle nudges can lose its potency for high-risk groups, reminders containing fller sentences may potentially be ignored by this demographic, etc.We identifed that simple and single goaloriented reminders may be more efective in encouraging veterans to complete their goals.We provided implications for future research and design including emphasizing the signifcance of design tailored to specifc contexts, identifying potential design elements to reduce cognitive load for peer mentors, and promoting the use of personalized user-centered persuasive design, such as semi-guided reminders to address the distinct needs of USMVs.
Engaging individuals with MH conditions as co-designers ofers a promising avenue to create designs that cater to the specifc needs of peer support networks [49,69].This shift in research methodology has the potential to yield meaningful outcomes, addressing the distinct challenges and goals of these communities necessitating comprehensive research in Human-Computer Interaction (HCI).Our study contributed to this landscape of research by adding to the knowledge regarding the important considerations while designing persuasive technologies for USMVs and a better understanding of the structure and language used for text reminders in mental health peer support contexts.

RELATED WORK
In this section, we conducted a thorough examination of prior research on peer support interventions using mobile technology, particularly within the context of USMVs).We also explored the theory and potential efectiveness of Persuasive Reminders in driving successful interventions for behavior change.

Peer-based Digital Interventions
We use the term 'peers' to refer to individuals who share similar health conditions and limitations, particularly those facing mental health (MH) challenges.Peers with MH issues collaborate by sharing their experiential knowledge, ofering mutual emotional support, and fostering a sense of hope within the community.Peers have assumed diverse roles within the realm of MH care, ranging from organizing support groups to occupying traditional positions within clinical settings [32].Peer interventions for various MH conditions have demonstrated a signifcant impact on treatment outcomes when compared to standard care [25] such as alleviation of symptoms, enhancement of prosocial behaviors, and improved engagement with treatments [9,10,68].
In recent years, peer-based interventions have undergone a noteworthy transformation facilitated by various digital platforms, including but not limited to social media [41], online forums [26,67], and mobile applications [30,37].In addition to more traditional modes of support, such as telephone calls and text messaging, online peer support communities have emerged as instrumental components in the management of various medical conditions [27,55].Studies have demonstrated the efcacy of these digital interventions in the context of illnesses such as breast cancer [13,32], rare diseases [44], and epilepsy [34].The allure of online peer support is a signifcant motivating factor for individuals seeking MH assistance within digital spaces [61].Individuals fnd solace in connecting with peers who share similar conditions, thereby facilitating the exchange of information, provision of emotional support, and the dissemination of practical advice [55,78].This preference for online avenues for MH support is often attributed to the benefts of anonymity and convenience [60,61].

Peer-based interventions for USMVs.
USMVs can sufer from a range of MH issues stemming from their service experiences including Post-Traumatic Stress Disorder (PTSD), depression, anxiety disorders, substance use disorders, Traumatic Brain Injury (TBI), suicidal thoughts, and other mood disorders [22].Veterans may also contend with the efects of Military Sexual Trauma (MST), adjustment disorders during the transition to civilian life, and various co-occurring MH challenges [33].The Veterans Administration (VA) MH Strategic Plan recognized the value of peer support to help with many of these MH illnesses and called for the formalization of peer support within the VA, emphasizing criteria such as afliation, lived experience with a similar illness, the peer provider's successful engagement in recovery, and certifcation in peer support competencies [11,47].Promising outcomes have been observed when applying peer support to veterans with MH concerns in suicide prevention [8], civilian life reintegration etc. [47].
The rapid proliferation of smartphones and the development of self-care apps present new opportunities for providing MH services to USMVs.These apps ofer advantages by overcoming barriers to accessing care and granting patients a private, self-directed, and readily available option for their MH needs [50].Government entities like the VHA (Veterans Health Administration) and the Department of Defense (DoD) have invested signifcant resources in developing mobile apps to address various MH issues, with emerging evidence supporting their efectiveness, particularly in reducing symptoms related to MH concerns [24].Prior literature suggests mobile-based VA services can reduce healthcare cost and increase self-management ability [14] and because of the convenience and accessibility, veterans are increasingly interested in obtaining care via mobile devices.[64].Veterans with serious MH conditions beneft from technology-mediated peer support, showing improved symptom self-management [7,12,18].Prior research in HCI has also highlighted the positive impact of using digital tools to assist in the challenging shift from a military culture to civilian life [69].Examining the role of digital tools in shaping cultural and economic practices among veterans has the ability to provide information on their state of mental health concerns [6,7,43].Seeman et al. demonstrated the value of connecting with a human network to aid veterans in grasping unfamiliar societal norms and accessing support during their transition [70].Additionally, Zhou et al. found that this particular community exhibits more informational and emotional support behaviors compared to general online communities, with a higher prevalence of informational support [79], which contrasts with the potential for successful peer support interventions.Mobile technologies enable peer-to-peer support, which saves time and efort [55].Mobile technologies let people feel much more at ease while interacting and sharing their experiences because the issues are less evident [26].
Peer-support intervention through mobile technology is still at its early stage [48].While commitment to the treatment process and continual engagement in therapies are critical [77], evidence suggests that patients receiving care through mobile technologies, notably through mobile MH apps, have a poor rate of adherence [19].Montena et al. pointed out several barriers in the mHealth peer-supported implementation of MH mobile apps among veterans.These challenges included a lack of implementation infrastructure, insufcient training for peers in mHealth, and inefective promotion of mHealth, and put an emphasis on advocating for technology that is easily implementable, requiring minimal technological literacy while providing maximal benefts.[48]) There is a clear need for strategies that can boost user engagement with these promising tools.In this context, the development of persuasive technology emerges as a particularly promising avenue worth exploring.This approach aims to leverage design and technological elements to motivate and engage users more efectively, ultimately enhancing the utility and impact of mobile MH apps [57].

Persuasive Reminders and Behavior Change
Persuasive technology, defned by Fogg, aims to change attitudes and behaviors through interactive computing systems.The Persuasive Systems Design (PSD) model enhances this concept, categorizing persuasion principles into four groups: Primary Task Support (PTS), Dialogue Support (DS), System Credibility Support (SCS), and Social Support (SS) [20].These principles help design webbased interventions that reinforce, change, or shape attitudes and behaviors [20].PTS facilitates primary activities, DS keeps users motivated, SCS enhances credibility, and SS leverages social infuence [2,20].Prior literature have primarily focused on the overall efectiveness of persuasive technology systems, with most reporting positive outcomes, particularly in health and exercise domains and explored the presence of persuasion principles like tunneling, tailoring, reduction, self-learning, reminders, social facilitation within these systems [46,56].Among these principles, persuasive reminders have demonstrated their efectiveness in combating low adherence to mobile support interventions [55].
Persuasive reminders leverage social support to enhance task recall and boost confdence, ultimately driving behavior change through motivation, ability, and triggers [42].Efective reminders align the trigger timing with individuals' motivation and capability for task execution [45].While conventional health reminders mainly focus on triggering tasks promptly, in cases of reduced motivation or capability, individuals can beneft from triggers that facilitate and motivate task completion [36,45,57].These facilitators and motivators, as termed by Fogg, difer from mere signals that serve as reminders [57].From information processing and cognitive consistency perspectives, the Elaboration Likelihood Model and the infuence techniques theory state that there are two routes to persuasion, a central and a peripheral route [31,59].Previous research has identifed design elements that heighten motivation and ability, thereby promoting the accomplishment of health-related tasks and goals.Simple persuasion techniques, such as daily check-ins [40], gamifcation reminders [3], and self-monitoring [51], tailored reminders are generally perceived as helpful features in mHealth applications [46].Designers of persuasive reminders often incorporate evidence-backed strategies like performance feedback, rewards, authority, progress tracking, and social infuence, which have shown efectiveness in motivating changes in health behavior such as health self-management [57], such as managing chronic illnesses [58], MH care [75], physical health [45] etc.
Persuasive reminders has potential in helping people, including USMVs, manage their MH outside of clinical settings.These reminders are diferent from short-term behavior prompts because they involve signifcant lifestyle changes and need to be considerate of users' vulnerabilities [43].Promoting self-adherence via various persuasive cues like daily check-ins, gamifcation, reminders, and self-monitoring represents has the potential to enhance the efectiveness of mentor-mentee communication [28].Franco et al. has also proposed that persuasive technologies, including personalized reminders and in-app texts, in fostering healthy habits and improving adherence rates to care interventions among frst responders and military personnel [21].Persuasive reminders can also be contrasted with specifc customs prevalent in military cultures, incorporating elements like roll calls and the completion of daily activities.By integrating these reminders into familiar military routines, they can seamlessly blend with established practices, fostering a sense of continuity and familiarity among individuals within the military community [63].
While healthcare has established strategies for behavior change, applying them to MH reminders, especially for USMV community, is relatively unexplored and the extent to which these strategies are efectively implemented in MH apps for veterans remains unclear.Our research focuses on developing persuasive reminders within mobile MH apps to facilitate peer support interventions, collaborating closely with USMVs to tailor the system to their specifc needs.Taking into account the distinctive requirements of the veteran community due to their diverse backgrounds and activities [49,79], it is crucial to acquire their insights to enhance engagement and communication among peers involved in a peer support intervention aligning with broader objectives.

BACKGROUND
In this background section, we ofer a brief overview of the signifcance of collaborative research and community engagement, our partnership with "Dryhootch of America" [54] within the US military veteran (USMV) community, and the mentor-mentee dynamics within the context of peer support interventions facilitated by the Dryhootch of America [54].

Collaborative Research and Community Engagement
Community-engaged research values the collaboration between external researchers and community-based organizations.It acknowledges that both bring unique perspectives, with researchers contributing knowledge and trust, and communities ofering insights into assets, concerns, values, and activities.While researchers may lack in-depth understanding of specifc health issues, community members may be unfamiliar with research methods.Yet, the synergy of these perspectives often uncovers common ground, enriching the research process and outcomes through shared interests, needs, and mutual respect.Collaborative research approaches through engaging USMV community is no diferent.The feld of veteran community engagement is evolving, drawing insights from traditional community-based participatory research, veteran studies, and the active involvement of veterans themselves [22].This collaborative research model, with USMVs, as co-researchers, is advancing a design-thinking perspective in social and healthcare systems tailored for this unique population.This approach has opened up a wide avenue of research topics, spanning from innovative interventions for PTSD to veteran reintegration strategies, addressing changes in veteran identity, fostering community coalitions, and exploring various aspects of veterans' experiences and needs.These eforts represent a dynamic evolution in understanding and supporting veterans within their communities.

Collaboration with Dryhootch of America
In an attempt to engage with the community, we have partnered with "Dryhootch of America" [54], a non-proft veteran led, veteran serving community organization headquartered in Milwaukee, faculty members from the Milwaukee VA and Medical College of Wisconsin.Descriptions of this community-academic partnership, the Dryhootch of America Partnership for Veteran Health, its formation, and lessons learned are detailed in [6,7,22,64,65].The collaboration has grown over a decade involving multiple academic partners with Dryhootch of America as a hub organization in the veteran community that supports veteran MH centric research and recruiting [64].This organization has deep experience in peer-topeer MH services to USMVs sufering with civilian reintegration after service including PTSD, homelessness, drug addiction, food insecurity, difculty fnding work, obtaining veterans benefts, getting back into school [6,7,64,65].

Mentor-Mentee Dynamics in Peer Support
Intervention Through Dryhootch of America "Dryhootch of America" drives a peer mentorship program designed to provide peer support to these veterans [54].A peer mentor, in this context, is a veteran who has experienced challenges during their transition to civilian life.Peer mentors play a crucial role in assisting "peer veterans" (In a broader sense -peer mentees) during this transition, especially when they understand expectations and can anticipate potential mental health crises early on.Peer mentors provide a secure and empathetic environment for their peer mentees to communicate and seek support, fostering a strong connection due to their shared military backgrounds and trauma experiences.Their role involves regular check-ins with mentees via mobile apps, phone calls, or text messages, ofering resources related to housing, employment, Veteran Afairs, medical care, and self-care.Given the mental health challenges some mentees face, including alcoholism and substance use disorders, peer mentors ofer assistance by setting recovery goals, providing guidance on recovery processes, and motivating them to pursue positive life prospects.Furthermore, due to the signifcant past traumas and current living conditions, mentees often grapple with severe mental health conditions and potential triggers that can lead to crises.Peer mentors remain vigilant to efectively address these situations, and some of them ofer their support around the clock, ensuring immediate assistance when needed.

"
Batlepeer": peer support smartphone application."Battlepeer" smartphone application was developed to mimic a human-to-human peer support model for veterans struggling with civilian reintegration, with USMVs participating in an intensive, multi-month collaborative design process to provide initial user requirements and interface ideas, ongoing feedback for app refnement, and fnally to recruit veterans to use the system [53].This application features two interfaces based on the user profle created at the outset.It facilitates the matching of mentors and mentees, and once mentees are assigned to specifc mentors, they are given the opportunity to create their mentee profles.In this profle, mentees can use either their real names or pseudonyms, select avatars, indicate their ranks, and specify the military branch with which they were afliated.As mentees, they gain access to mentor information, including names, phone numbers, and military backgrounds.They can also engage in daily check-ins using a basic self-report data collection method through an Ecological Momentary Approach (EMA) [65,66].On the contrary, peer mentors can create profles as mentors and access all the contact information of their mentees.Mentors also have the ability to view descriptive visualizations of the check-in survey inputs from each of their mentees (Figure 3), aiding in mentor decision-making.For both mentors and mentees, the app includes a community chat and resource-sharing feature covering self-care, VA, transportation, employment, and more.Its main goal aligns with the mobile peer support trend, enhancing communication between peer mentees and mentors.

METHODS
Our study consisted of three phases: in the frst phase, three focus groups were conducted, the fndings from these focus groups guided the design of persuasive reminders in the second phase, and in the third phase, we conducted two participatory design workshops to improve the design by embedding inputs on specifc values of the stakeholders.

Participant Recruitment
For the focus groups, we recruited a total of ten peer mentors (eight male, two female) as participants through our partnership with the Dryhootch of America [54] dedicated to veteran welfare by giving an open call for peer mentors.Participating in this study was completely voluntary and participants could opt out at any time without penalty or loss of benefts to which they were otherwise entitled.The participants' age ranged between 25 and 69.They worked in diferent branches of the military including army, navy, marine corps, active duty, and reserves with highest in army.Four of them identify as African-American, fve as White, and one chose not to disclose their preference.Their mentoring experiences varied from 0 years to 10 years.They all have gone through the peer mentorship training programs facilitated by the Dryhootch of America and other facilitators.

Data Collection and Analysis
We collected data through discussions and cognitive assessments involving drawings and sketches in the focus groups.Here, we describe the process of data collection,analysis and design followed in the three distinct phases.Figure 1 outlines these stages.

Phase 1:
Identifying strategic application areas for persuasive reminders.In the initial phase, we conducted three focus group sessions, each spanning about 60 minutes.Following each focus group, two researchers conducted a debriefng session to document their initial impressions of the discussion, as well as any notable highlights, concerns, or immediate conclusions that had arisen.During these sessions, we inquired into the values and prerequisites necessary for crafting persuasive reminders within this particular context.The discussions centered around the frsthand experiences of individuals serving as peer-mentor veterans within a peer-mentor support system, focusing on their roles in supporting peer mentee veterans.We posed open-ended questions concerning engagement-related issues related to such interventions.The discussions were guided by an interview protocol but aimed to foster open dialogue.In one of these sessions, to illustrate the concept of persuasive reminders and stimulate creative input for future design, we also presented various low-fdelity prototypes of persuasive reminders that had already been employed in health-related contexts for diferent demographics, to get the participants acquainted with the concept of persuasive reminders.We sought feedback from our participants to discern which features were deemed valuable, required refnement, or should potentially be discarded.The initial focus group sessions primarily concentrated on the users' needs, perspectives, and concepts pertaining to reinforcing their ongoing commitment to the treatment process, with a particular emphasis on the role of persuasive reminders.These focus groups took place between September 2022 and December 2022.

4.2.2
Phase 2: Development of exemplary scenarios of persuasive reminders.Following the initial set of focus groups, a 12-week period from January 2023 to March 2023 was dedicated to the analysis of the data gathered during these sessions, with the aim of identifying strategic areas for the implementation of persuasive reminders.The audio recordings and accompanying notes were meticulously transcribed and anonymized by two of the authors.Subsequently, the collected information was organized according to specifc questions and thematic categories, drawing upon established thematic analysis methodologies [38,52].By discerning recurring key concepts that emerged throughout the focus group discussions, the principal themes and ideas relevant to our study's inquiries were derived.
Over the following 8 weeks, spanning from April 2023 to May 2023, we crafted exemplary scenarios for persuasive reminders based on the insights gleaned from our initial focus group sessions and informed by existing literature on persuasive reminders [45,57].Paper prototypes of these scenarios were designed.These designs underwent thorough careful examination and discussion with two subject matter experts, comprising an experienced peer mentor veteran and a professional psychologist.The professional psychologist, with nearly two decades of academic experience, has worked closely with the USMVs and served as a psychologist in a reputable medical college and veteran afairs.He is afliated with diferent local organizations dedicated to veteran welfare and has published many peer-reviewed research articles on this topic.The experienced peer mentor veteran not only served in the Vietnam War but has also been an active mentor for over a decade, contributing to veteran welfare.He has participated as a researcher in multiple studies conducted by these collaborative efort.These experts played a crucial role in helping us understand the appropriate contextual language, predict potential responses, and determine the optimal way to present prototypes to the participants.Multiple rounds of improvements were carried out before presenting the fnal versions to the participants.We ended up with fve distinct scenarios, each with two illustrative examples showcasing notable diferences in language and underlying persuasion techniques.A detailed description of these scenarios is presented in section 5.2.

Phase 3:
Exploring underlying values and needs for efective persuasive reminders.In the fnal phase, two sessions of participatory design workshops has been arranged in June 2023.It began with a brief presentation of some researchers' ideas about the proposed intervention, building upon the results from the frst workshop.The second part involved presenting researchers' ideas on the proposed scenarios, followed by collecting participants' opinions and refections on the proposed concepts and intervention features.The prototypes of the scenarios were printed in a large A3 paper with enough room on all sides, so that participants can write or draw sketches to present their own ideas and comments.(The study protocol for the participatory design workshops has been provided in the supplementary material section).These written expressions and drawings assisted us in grasping their thought processes regarding how we could tailor these reminders to better suit their individual needs.In certain instances, they composed entire texts that resonated with them, marked or circled words or sentences they found ftting, and utilized emojis to convey their approvals or disapproval.In some cases, we observed more drastic measures, such as crossing out entire sections of text or placing sticky notes over the content to indicate their disapproval.2 illustrates a selection of photographs captured during our sessions.In one of the images, we observe a peer mentor wearing a marine hat while jotting down their own comments.Meanwhile, other peer mentors, including members of the LGBTQ+ community, are actively engaged in the process.The image in the top right corner presents a scanned rendition of a sketch created by one of the peer mentors during one of the sessions.Our aim was to gain a deeper understanding of the intricacies of mentors' decision-making processes when responding to these notifcations and to explore the context and rationale behind their responses.Two researchers from the team were present in them and took detailed notes of their involvements and comments.Subsequently, the audio recordings were transcribed and anonymized by two authors.The analysis comprised two phases.Initially, after becoming familiar with the data, we initiated the frst phase by generating over 50 open codes to capture essential concepts from the participants.The relatively high number of open codes aimed to meticulously capture the nuanced insights within each discussion and was subsequently signifcantly reduced through the processes of memoing and clustering [38,52].In the subsequent phase of analysis, we utilized a constant comparison method, specifcally operationalized as afnity mapping, to memo and cluster the codes.This involved comparing each open code to others, positioning them based on their afnity to emerging themes and clusters, and exploring relationships between these themes.The ongoing process of constant comparison and collaborative discussions among the authors, who were domain experts, ensured the refnement of themes, resulting in a comprehensive and coherent representation of the data.Ultimately, a clear narrative was crafted to convey the identifed themes, substantiating the fndings with illustrative quotations and examples.

Data Integrity and Ethical Considerations
Considering that the discussion revolved around sensitive issues, we made sure to carefully consider the ethical implications of our work and to protect the rights of the participants.All sessions were recorded with participants' consent.The data was anonymized, with each dataset assigned a random code number in place of any personal identifers such as participants' names or other identifying information.The study was approved by the Institutional Review Board (IRB) of the authors' institution.

Positionality
The research team was composed of individuals from three distinct felds of expertise, including three domain knowledge experts, one seasoned psychologist with a background in working with USMVs, two profcient peer mentors, and two researchers.One of these researchers specializes in intersectional stigma, online social support, and mental healthcare, while the other is an expert in working with marginalized and vulnerable populations.The entire group actively participated in all aspects of the study, including designing the research, recruiting participants, and conducting both data collection and analysis.During the data collection stage, one of the researchers and two domain experts (the psychologist and one of the peer mentors) were present in all focus groups and participatory design workshops.These experts played a crucial role in facilitating the data collection process, ensuring the discussions ran smoothly, and ofering guidance to the researchers in managing specifc situations, such as maintaining coherent discussions and helping participants understand the topics in their terminologies.Furthermore, the presence of psychologists served as a precautionary measure to address any unforeseen situations, given that these veterans are highly susceptible to crises and can be easily triggered by sensitive discussion topics.Collectively, this team brings extensive experience in conducting collaborative, community-engaged research with USMVs, with some members having dedicated over a decade to this endeavor and the rest having more than two years of involvement in such research initiatives.
Furthermore, in pursuit to gain deeper insights into the dynamics of peer mentor-mentee relationships and to comprehend how peer mentors establish trust, provide support, and defne the nature of their assistance, two members of the research team actively participated in weekly peer mentor meetings from January 2023 to August 2023.These observations assisted them in establishing a strong rapport with the peer mentors and gaining a deeper insight of the military context within the peer support intervention.

Limitations
Regarding data collection, we chose to engage only peer mentors in the initial phase, as we decided not to involve peer mentees due to their vulnerable state.However, it's worth noting that all the peer mentors themselves have either experienced being a peer mentee or have dealt with mental health-related issues.Furthermore, their close connection with their mentees and formal training of peer mentorship allowed them to efectively explore the needs and values of their mentees during the design process.

RESULTS
The study was structured into three distinct phases.Phase 1 fndings were instrumental in formulating strategies for the application of persuasive reminders in this context.In Phase 2, we developed these persuasive reminders based on the strategies.Finally, in Phase 3, our fndings shed light on the essential values and requirements that should be integrated to enhance the efectiveness of these reminders.

Findings from Phase 1: Strategic Application Areas for Persuasive Reminders
To determine the optimal areas for deploying persuasive notifcations, we initially conducted multiple focus groups to identify the domain-specifc expertise needed.Our analysis of the feedback from peer mentors revealed a range of contexts where these persuasive reminders could be highly infuential.

5.1.1
Reminding mentors to maintain communications with their mentees.Peer mentors are the individuals who willingly ofer support to fellow veterans facing mental health issues, leveraging their shared experiences.However, these mentors have their own lives, family commitments, and job responsibilities, making it challenging to strike a balance between their personal obligations and their role as mentors.The need to minimize their cognitive load is evident since constantly thinking about their peer mentees and support groups is not a viable option.One of the peer mentors said -"I used to but I can't aford to do it for my own mental health, to take it home all their stuf.This is not an easy pace to me." On the other hand, peer mentees are in a vulnerable state and may experience crises at any time, requiring immediate attention and support.Given that these peer support groups operate through various mobile applications, where peer mentees are responsible for daily or weekly check-ins, these check-in results can serve as a valuable resource.Figure 3 shows such a snapshot from the "Battlepeer" smartphone application [53]ema displaying concerning check-in results from peer mentees, possibly warranting immediate attention.They can be leveraged to trigger more efective notifcations when any of the mentees encounter issues related to their daily activities or mental health.This approach will help strike a balance between providing timely support and alleviating the cognitive burden on peer mentors 5.1.2Reminding mentees to complete check-ins through the app or phone.In a peer mentor-mentee support group, maintaining regular communication between mentors and mentees is of utmost importance.This ongoing interaction allows mentors to assess the current situations of their mentees, enabling them to provide the necessary support and attention when needed.However, there are instances where mentors encounter difculties in reaching their peer mentees.One of the peer mentor said "you know, whether he went two months without talking to me and ignoring my calls to the last trial for help, and what should I do?"In such cases, deploying persuasive reminders to motivate mentees to reengage in communication with their peer mentors can prove to be highly efective.These reminders can be served as a gentle nudge to encourage mentees to reconnect with their mentors, ensuring that the crucial lines of communication remain open for support and assistance.

5.1.3
Alerting peer mentees to immediate support during early crisis situations.As per insights from peer mentors, it's important to recognize that peer mentees may fnd themselves in an early crisis situation or experience escalating negative thoughts at any given time.Leveraging their experience and training, peer mentors possess the ability to identify these critical situations and take proactive steps to provide assistance.
However, according to mentors, a common challenge arises when mentees tend to isolate themselves and discontinue communication during such difcult periods.Prior literature further highlights the challenge that USMVs encounter when it comes to openly sharing their trauma and related events with their family members [28].In such instances, it becomes essential to proactively remind these mentees of the available support networks and resources they can access.The objective is to motivate and encourage them to reestablish communication, ensuring they are aware of the assistance and guidance that remains at their disposal during challenging times.

Prompting peer mentees to access available wellbeing resources.
During our conversations with peer mentors, they have consistently emphasized a fundamental aspect of their role, which is to provide valuable resources related to self-care, medical facilities, housing, and employment to their peer mentees.Whenever mentors come across resources that could signifcantly beneft their mentees, they are eager to share this information.However, a challenge arises when mentors are unable to establish contact with their mentees.
In such situations, it becomes crucial for mentors to regularly remind their peer mentees about the existence of these valuable resources that can signifcantly contribute to their well-being.These reminders serve as prompts to ensure that mentees are aware of and can take advantage of the available resources that can enhance their overall quality of life.By maintaining open lines of communication and providing these timely reminders, mentors can better fulfll their role in supporting the well-being of their mentees.

Exemplary Scenarios of Persuasive Reminders
Based on the values and criteria identifed in Section 4.1, we have developed fve distinct persuasive reminders, each meticulously crafted with unique language and motivational elements.We considered O'Leary et al. 's taxonomy of persuasive reminders for health self-management that discusses four diferent types: introspective, socially supportive, adaptive, and symbolic [57].Introspective reminders serve as prompts for individuals to contemplate their health goals, helping them plan and prioritize their daily healthrelated tasks.These reminders are timely and trigger self-refection on daily activities, encouraging individuals to prioritize their mental well-being.Initiating these reminders ahead of tasks is crucial for fostering participants' awareness of their health journey and placing their health-related tasks in context.In contrast, socially supportive reminders are designed to cultivate motivational and mentoring relationships, enhancing users' confdence in performing health-related tasks.Adaptive reminders are tailored to persuade users by adjusting to their unique preferences and characteristics.Lastly, symbolic reminders motivate individuals to engage in health tasks by evoking personally signifcant reasons for adopting healthy behaviors [57].Below we describe the fve scenarios of sending persuasive reminders under this taxonomy, which are further summarized in table 1.Throughout the rest of the paper, we use the pseudonyms Josh and Kevin to represent a peer mentor and a mentee veteran respectively.

Scenario one.
The reminder is designed to be sent to the peer mentors automatically to ensure that they maintain contact with their mentees.Introspective reminders hold signifcance here, primarily concerning the task of reminding mentors to maintain continuous communication, especially when mentees require urgent attention due to their specifc mental health conditions.We presented two options to the participants, each with distinct characteristics.Example A takes a more direct approach by clearly identifying which mentees require extra attention.It doesn't require mentors to log in to the application, as they can connect with their mentees through alternative means like personal phone, email, or social media, enabling them to take immediate action.other hand, Example B empowers mentors to identify critical cases independently within the application.When they receive notifcations, mentors are expected to access the application and assess the situations on their own.This approach also grants mentors the fexibility to reevaluate which mentees they want to follow up with.

Scenario two.
This reminder is intended for peer mentees.We've introduced two options for consideration.Example A features a text with a distinct value proposition.It leverages a successful past instance to inspire peer mentees to establish a connection with their peer mentors.Conversely, Example B adopts a more generic and non-invasive approach.It aims to gently encourage mentees to fnd motivation in engaging with their mentors.This is an example of a socially supportive reminders where motivational factors and mentorship values have been incorporated.

Scenario three.
This scenario incorporates elements from both introspective and socially supportive reminders.As part of the peer support group, it's the responsibility of mentees to fll out an EMA survey during daily/weekly check-ins [53].This reminder aims to encourage peer mentees to stay motivated and complete their weekly check-ins.We've provided two diferent examples, each with distinct approaches.Example A motivates peer mentees by reminding them of their past accomplishments in completing these check-ins, using positive reinforcement as a motivational tool.
In contrast, Example B focuses on motivating mentees by emphasizing the deadlines for completing the surveys.Our intention here is to explore what works best for the mentees-whether positive reinforcement or deadlines prove to be a more efective motivator.

Scenario five.
This fnal reminder serves as a conversation starter between mentors and mentees, helping to bridge any communication gaps that may arise due to conficting schedules.Similar to scenario 4, adaptive reminders are the the most suitable choice for this scenario.In Example A, the reminder alerts peer mentees about new resources, providing a specifc conversation point to rekindle their interaction.Additionally, by including the phrase "please remind me, " it encourages mutual accountability in sharing important resources or information.Example B, on the other hand, is left open-ended and blank, allowing mentees to suggest topics or ideas for reconnecting in case of a time gap.However, it's worth noting that in this case, the mentor takes on the sole responsibility by saying "I'll tell you," which could imply greater control over the conversation and information sharing.The objective is to explore the level of control or accountability that both parties are comfortable with when it comes to reestablishing communication.

Findings from Phase 3: Underlying Values and Needs for Efective Persuasive Reminders
We organized two sessions of participatory design workshops to gather feedback on the design of our fve unique reminders.The participants provided invaluable feedback and suggestions concerning various aspects, including strategies for personilization, providing encouragement, creating actionable reminders, increasing mutual accountability.Table 2 presents a brief overview of participants' feedback on fve scenarios and uncovered strategies.

Strategies for personalization.
Past research has shown effectiveness of personalization in persuasive technologies [72].Our participants pointed out a few techniques for personalizing the persuasive reminders including the use of receiver's name, emoticons, and context specifcity.

Address with names:
In an efort to make text notifcations more personalized, we incorporated the names of peer mentors and mentees into various parts of the messages.Initially, we used greetings like "Hey Kevin" (a pseudonym for a peer mentee) and "Hey Josh" (a pseudonym for a peer mentor).Our participants pointed out that, the efectiveness of personalization through names depends on the context and purpose of the communication.For example, in this case, despite addressing with names, the inclusion of generic greetings could lead to a loss of interest among peer mentees.They were concerned that this might give the impression that the messages were automated, ultimately undermining their motivational impact.However, they express a preference for the design presented in scenario 4, specifcally example B, where the message initiates with a simple "Hey."Additionally, they suggest making the greetings less formal by using phrases like "Hey buddy" or "Hey man." However, in the scenario of alerting peer mentors about a specifc mentee needing immediate attention (example 1A), participants found it powerful and motivating.This personalized approach inspired them to take quick action through their preferred communication medium.They preferred this version over example 1B, where the focus is on encouraging mentors to use the mobile application to check on mentees that require attention.Moreover, receiving multiple reminders, one with each alarming participant name would be more efective, according to the mentors, as it would encourage accountability, too.They argued that if many of their mentees are struggling, since they usually follow similar mentoring techniques for all the mentees, the rest might be struggling, too.They would feel the urge to check on other mentees as well, to make sure that they are okay.
"If I receive four diferent texts with four names and I have six mentees in my support group, which will mean, Man, I am not doing a good job and this will in turn motivate me to contact with all the mentees instead of that four." In summary, the use of names should be tailored to the particular context and the preferences of both mentors and mentees to achieve the desired level of engagement, motivation, and accountability.
Use emojis: Emojis can be helpful to communicate sentiment, and to improve communication and understanding.As we did not include any emoticons in our example scenarios, the participants placed a strong emphasis on the need for using humor and the inclusion of emoticons in order to humanize the communication.They believed that incorporating these elements would not only make the messages feel less automated but also infuse a sense of sentimentality into the interactions.By tailoring the language for particular mentees based on their relationships and previous communication styles with the mentor, and by injecting humor and emoticons into the messages, the participants can foster a more genuine connection.These small touches of personality and emotion were seen as essential in transforming routine reminders into meaningful and engaging exchanges, ultimately enhancing the overall quality of communication.The following example is from a participant's ideation showing the use of emoticons infusing a touch of humor to make the situation feel more relaxed and normal.It is essential for the mentors to make sure that mentees respond to check-in surveys through the app at least once a week, so that they are able to assess their mental health symptoms.The participant mentors discussed diferent approaches to provide constant encouragement, including adding success stories, identifying the level and type of motivation needed for each individual, addressing the triggers behind negative thoughts, and by careful consideration of words in the text content.
Encourage through past success stories: In Scenario 2, Participants emphasized the importance of a clear proposition tailored to the peer mentee's specifc situation.They suggested focusing on successful events or strategies that both mentors and mentees have used in the past.Sometimes peer mentors assist mentees with various challenges such as substance abuse, housing, transportation, connecting them with VA facilities, or helping them fnd employment.They suggested adjusting the clear proposition to revolve around successful events or strategies that both mentors and mentees have experienced.Participants also recommended providing options with a few examplary tones to enhance engagement and capture the mentees' attention.Participants also suggested that sharing anecdotes about their past successes in developing positive habits or accomplishing daily tasks could serve as a valuable strategy to motivate themselves and take initial steps toward enhancing their mental well-being.By recounting their own triumphs, they believed it would be easier to gain a foothold and begin the journey of improving their mental health.These personal stories would not only provide inspiration but also instill a sense of self-efcacy, empowering them to make gradual progress in their pursuit of better mental health.In essence, leveraging past achievements as a source of motivation and encouragement emerged can be a promising approach.One participant said if their mentees go to gym daily, a text should be something like -"Hey, you haven't been to the gym.Are you ok?" Understand the level of motivation needed: In Scenario 3, The participants emphasized the need for tailored and custom motivation.They acknowledged that some mentees consistently check in and respond well to a direct approach.For instance, they mentioned that for these mentees, a notifcation with a direct message such as, "Could you please check in on the app?" would sufce.However, others, who are less inclined to check in regularly, require a gentler approach.Instead of directly requesting check-ins, participants proposed an alternative approach that they found to be efective.They mentioned that while check-ins through the app are valuable, not everyone is enthusiastic about routine tasks like these.In such instances, initiating informal check-ins through text or phone calls should be prioritized.One participant gave such an example -"Hey, I have not heard from you, what's been going on?" Once they start feeling more comfortable, gently encouraging them to participate in app check-ins can be a successful strategy.Recognizing these diferences in motivation levels is crucial for efective communication.
Address triggers in addition to negative thoughts: In Scenario 4, where the text notifcation addresses sensitive topics like negative thoughts, participants stressed the importance of asking about the triggers behind these thoughts rather than just addressing the concern.Understanding the triggers assists them in determining the appropriate next course of action.However, they pointed out that obtaining answers to such sensitive topics requires highly customized options tailored to their needs.
Select terminologies carefully: While reviewing the scenarios, participants emphasized the importance of choosing words carefully when sending text notifcations to USMVs facing mental health challenges.They pointed out that certain words, such as "negative thoughts" and "crisis, " should be avoided for two signifcant reasons.First, using such terms might wrongly imply or assume that the peer mentee is in a crisis situation, potentially causing unnecessary discomfort or even triggering distress.Therefore, word choice in notifcations needs to be crafted with caution, ensuring sensitivity to the mentee's mental state.
Additionally, during the examination of Scenario 3, participants noted that words like "survey" should be avoided as they can make the peer mentees feel like they are part of an experiment rather than receiving genuine support.
Furthermore, participants highlighted the importance of recognizing words with diferent meanings in a military context.For instance, the word "tools" may have a distinct connotation in military terminology.To avoid potential confusion or misunderstanding, it was suggested that instead of using "self-care tools," the term "benefciary resources" should be employed to ensure clarity and relevance in communication with USMVs.This adjustment ensures that the language used is both respectful of their experiences and conducive to efective communication and support.

Strategies for creating actionable reminders.
Our study participants placed signifcant emphasis on the importance of crafting reminders that are actionable with a clear intent to initiate communication.Instead of resorting to fller sentences, they advocated for concise and purposeful reminders.Additionally, they highlighted the value of ofering direct guidance by implementing constraints in the available choices, making it easier for users to make decisions.Moreover, our participants stressed the need to strike a balance when designing questions.They recommended fnding equilibrium between open-ended inquiries that allow for thoughtful responses and yes/no questions that provide straightforward answers.This approach will ensure that the interaction remains engaging and informative while also facilitating efcient communication.
Show intent to initiate communication rather than using fller sentences: Our initial scenario involving notifcations sparked a discussion about the inclusion of unnecessary or fller language.None of the Scenario 2 examples was well-received as they contained excessive fller content.Mentors suggested that the messages should be actionable instead of false or unnecessary pretenses.
Rejecting both examples, participants took it upon themselves to propose their own text messages, and appeared to converge on a similar format.This format mainly involved prompting peer mentees to initiate communication when there had been a signifcant gap in their previous interactions.These messages typically consisted of two sentences: one mentioning the lack of recent communication and the other requesting a call or text to kickstart the conversation.For example, one of the participant wrote -"Been a few days since we talked.Hope all is well.Can you do a quick check-in on the app thanks" During the discussion, participants highlighted the issue of fller language when presented with Scenario 4 and Scenario 5. Their immediate reaction was that the text notifcations felt artifcial and insincere, describing it as "some AI nonsense."In multiple instances, peer mentors have put emphasis on the importance of carefully crafting the language to ensure it feels personalized and tailored.The use of generic and repetitive pushy language could lead to a loss of credibility toward the system.Peer interventions for USMVs prove efective because they are personalized and create a comfortable environment for exchanging support with those who share similar experiences.It's crucial for systems to emulate this personalized approach, providing users with a sense of familiarity and confdence akin to what they experience when interacting with their peers who have undergone similar situations.
Provide direct guidance through constraints in choices: In their attempts to explain how to make the notifcations actionoriented, our participants emphasized on motivating mentees break out of their isolation, particularly during the early crisis stages.Mentees often tend to isolate themselves from their daily routines and tasks during such times, which can lead to the accumulation of negative thoughts.Therefore, one of the top priorities should be to encourage mentees to get of the couch and engage in their daily routines.In scenario 5, participants mentioned instead of mentioning about the choices, providing direct guidance would be efective.
Participants suggested a more focused approach with a single coping strategy instead of ofering a choice among four diferent ones.This streamlined approach aims to provide clarity and direct guidance to the recipients to understand and implement the suggested coping strategy.
Strike a balance between open-ended and yes/no questions: Our participants mentioned instances where receiving a simple one-word response from their mentees become critically important, particularly when a mentee isolates himself, and the mentors have to repeatedly call or send texts for several days without getting any response.In such cases, they found that sending a text message that can be answered with a simple 'yes' or 'no' can be highly efective.
However, the text needs to be carefully crafted to strike a balance.It should convey a sense of urgency and concern, yet also reassure the peer mentees that they will be okay.It acknowledges that the veterans might need some time alone to gather themselves and regain their strength while letting them know that support is available when they're ready to reach out.For example, "Are you alive?Just let me know are you alive!" 5.3.4Strategies for increasing mutual accountability.To explore the shared responsibility of maintaining communication between mentors and mentees, each scenario in our notifcation system concluded with an actionable directive, such as "click it, " "call me, " or "remind me." In both Scenario 1 and Scenario 3, we implemented a convenient shortcut option for the respective user groups, i.e., peer mentors and peer mentees, allowing them to easily access the mobile application with just "one click."In Scenario 1, this feature primarily serves the needs of peer mentors, as they hold the responsibility of overseeing their peer support groups to identify those who may require additional attention.In contrast, in Scenario 3, this feature is tailored for peer mentees since they are solely responsible for completing the weekly check-ins.Although peer mentors might opt for direct communication with their mentees through alternative channels to remind them about completing check-ins, our participants generally expressed appreciation for having the option of automated reminder available.Now, in scenario 2 and 4, we framed the sentences ("Give me a call if you want to talk again", "Let me know what I can do for you") in a manner that placed full accountability on the mentee for sustaining communication between mentors and mentees.This approach was largely rejected by the participants.
"This "if" is a daydream" Rather than ofering excessive fexibility in the phrasing the message, participants suggested adopting a slightly more assertive tone.They recommended using expressions like "Could you perform a quick check-in within the app?" or simply "Please give me a call."This approach aims to gently encourage action and prompt engagement while maintaining a clear and direct communication style.In Scenario 5, the two examples presented signifcant diferences regarding the distribution of accountability.In Example A, there's a shared sense of responsibility for maintaining communication.By phrasing it as "please remind me," both mentors and mentees are encouraged to play their part in the process.Conversely, in Example B, mentors assume complete responsibility by stating, "I'll tell you," indicating that they retain control over to ensure that the information reaches the mentees.Participants favored the approach of Example A. It allowed for a safety net in case someone forgot due to their other responsibilities.With both sides sharing the responsibility, the likelihood of "information getting lost in the communication" is reduced.This mutual accountability contributes to a more robust and reliable system of communication, ensuring that important information is consistently conveyed and received.

DISCUSSION
Our fndings emphasize the importance of context-specifc design and the potential of semi-guided reminders to alleviate the cognitive loads on peer mentors.Furthermore, it highlights the need for a more comprehensive user-centered persuasion design approach when addressing the distinct requirements of USMVs

Thinking Beyond Traditional Steps of Design
We initially planned to follow the traditional steps of user-centered design (formative research → prototype → evaluate) [1]: to conduct a formative research to understand user needs of persuasive reminders to facilitate mentor-mentee peer support in the veteran's context, to utilize this understanding and data in designing persuasive reminders, and eventually evaluate these reminders in future.However, in order to conduct an ethical community based participatory research (CBPR) [76] we made sure to protect not only individual research participants but also the communities and the population.Contrasting the traditional user-centered design process, our approach includes an additional layer of validation before the actual development.We begin by comprehensively understanding the context and specifying user requirements, but before proceeding to evaluation, we prioritize validating aspects like language, motivational factors, and customization options in conjunction with the actual design.This iterative approach ensures that the design aligns closely with the needs and preferences of the community, enhancing its efectiveness in this specifc context.Our fndings have challenged traditional concepts related to the implementation of persuasive reminders, with a few notable observations.First, contrary to the established belief in the efcacy of personalized reminders that use the recipient's name as a motivational tool, our study suggests this strategy might sometimes undermine trust in sensitive contexts such as mentor-mentee relationships involving USMVs with mental health (MH) issues (Section 5.3.1).Second, while traditional persuasion principles favor a softer, non-aggressive tone utilizing gentle nudges to spur action [74], the approach can lose its potency, particularly with highrisk groups (Section 5.3.3).Reminders containing fller sentences tend to lose their impact and are easily ignored by this demographic.We advocate for a more straightforward communication strategy that invites short, one-or two-word responses, accommodating the potential lack of mentees' energy for extended replies, but still facilitates ongoing communication by encouraging brief feedback.
6.2 Implications for Future Research and Design 6.2.1 Context-specific design.To create reminders that truly resonate with this demographic, it is imperative to integrate veteran's perspectives into the design process.Prior study has shown that even after leaving the military, many veterans continue to live within the ideological framework of their military experience [43].Incorporating this context into veterans' daily lives is crucial for the efectiveness of interventions targeted towards them.Our research uncovered specifc nuances in communication with veterans that have important implications for designing persuasive reminders.It became evident that certain words should be avoided when crafting reminders (Section 5.3.2).Terms like "survey" can trigger a sense of being involved in an experiment, which they may not receive well.Additionally, the use of phrases related to "negative thoughts" may not be efective, as traumatized veterans often respond poorly to negative reinforcement.Even seemingly innocuous words like "tools" can carry a diferent connotation within the military context.These insights highlight that not all elements of language from prior research on persuasive technology are directly applicable for in this setting.
Furthermore, implementation of persuasive reminders often encourage guiding users with a wide variety of choices to facilitate decision-making as a part of empowering the users of making their own choice [71].Contrary to this, our fndings suggest that a more constrained approach to providing choices may be benefcial (Section 5.3.3).We identifed that during complex situations, tasking mentors with simple, daily responsibilities can be challenging, but engaging in these tasks can signifcantly improve their wellbeing.In such cases, simple and single goal-oriented reminders might be more efective.For military context, this approach can be likened to assigning a mission, motivating individuals to work diligently towards completion.These fndings highlight the importance of contextual design, particularly when supporting vulnerable populations like USMVs through peer intervention.It highlights that diferent groups have distinct approaches to recovery, emphasizing the need for tailored design strategies that consider the unique context and needs of the target population.6.2.2 Implementation of semi-guided reminders.Using past success stories as a persuasive technique is a well-established method to motivate individuals to complete future tasks [4].In contrast, our research highlighted that employing generic success stories may not be as motivational as tailoring them to individuals' specifc situations (Section 5.3.2).Furthermore, mentors emphasized that diferent mentees require varying approaches to motivation.Some respond well to a direct approach, while others beneft from a more gentle tone (Section 5.3.2).
In this context, incorporating human involvement, such as peer mentors, can be advantageous.Peer mentors possess a deep understanding of their mentees' current situations and can efectively gauge the most suitable motivational approaches.This insight can be leveraged to implement semi-guided persuasive reminders, where a range of exemplary tones for reminders is presented, but peer mentors retain control in setting up these reminders.Peer mentors can be allowed to customize the communication style and type of the digital reminders in a few ways : (a) they can be shown option to choose between a more direct approach or a gentler tone (Section 5.3.2),(b) they may have the authority to prioritize the types of reminders sent to specifc peer mentees.For example, some mentees who are proactive and do not require to be frequently reminded to complete check-ins, might beneft from reminders about available resources instead, (c) interactive reminders with quick and easy responses can be sent, facilitating the fow of information that mentors need to better understand the situation.. Prior literature suggests that semi-guided interactions can be particularly benefcial during vulnerable stages when individuals are dealing with signifcant concerns [37].This approach helps the system extend its reach and prompt early intervention when needed.These fndings underscore the importance of not relying entirely on automated texts.It is essential that peer mentors are provided with sufcient fexibility within the system to customize various aspects of the communication, ensuring a more personalized and efective mentor-mentee interaction.. Another design recommendation involves implementing a "Battle Buddy" system for the mentees, drawing inspiration from the United States Army's practice of assigning partners to soldiers.In the military, a battle buddy is tasked with providing support to their partner, both in combat and in other aspects of military life.This concept can be adapted to peer support interventions, where the role of supporting each other is paramount [62].While the battle buddy concept has been explored in prior literature [49], with buddies responsible for preventing negative thoughts and, in extreme cases, suicide, it has its drawbacks, particularly when pairings are not well-matched [5].However, in the context of peer mentormentee support interventions, where mentors often shoulder these responsibilities, the battle buddy system can be employed for minimal interactions.A battle buddy's role would primarily involve monitoring their partner's activities, ensuring they complete daily tasks and check-ins with their mentors.This military concept can be particularly useful in designing "Socially supportive reminders" [57] that involve motivational and mentoring relationships.This type of persuasive health reminders have been used to leverage social support to not only remember tasks, but to increase confdence in performing them [57].In our context, two peers can be teamed up by mentors to achieve some goal (e.g., complete weekly check-ins) and one peer can send reminders to the other peer about going through the activities.Then at the end of some achievements (e.g., if both complete check-ins in a timely manner), they both get rewarded.Veterans share similar values and experience, and thus can relate better to each other, making this type of gamifcation work well.Moreover, buddies can exchange information, allowing them to be aware of each others' situations.If a buddy is equipped with similar or adjusted access to generate semi-guided reminders, that can help relieve cognitive loads from the mentors to some extent as well.The customization of notifcation settings would be determined by the buddies themselves, and they would serve as an additional layer of intervention to assess the current situation of a peer mentee.Subsequently, they can report back to peer mentors, who can then take appropriate measures as needed.

Implications for Reducing Cognitive Loads of Peer Mentors
Our fndings related to strategic areas where persuasive messages can be employed (Section 5.1) have implications for alleviating the cognitive loads on peer mentors, thus enhancing the efectiveness of peer support interventions.Therefore, our initial focus was to pinpoint strategic areas where these persuasive reminders could be most benefcial.Peer mentors were enthusiastic about the concept from the the very beginning and acknowledged its potential to reduce the cognitive load on peer mentors.Peer mentorship is a demanding role, often undertaken voluntarily out of goodwill.However, our fndings illuminated instances where peer mentors experienced a signifcant mental workload.Each mentor is potentially assigned several mentees, each with unique expectations and support requirements from their mentor.Furthermore, mentors themselves frequently deal with their personal MH challenges.In this scenario, managing efective communication with all mentees can be a time-intensive task and may contribute to a signifcant cognitive load for the veteran mentors.Periodic reminders can play a crucial role in reducing mentees' cognitive loads, especially for those facing MH challenges.Managing multiple medications and therapies can complicate memory issues, hindering their ability to remember important tasks or self-care routines.Integrating persuasive reminders through a digital platform helps alleviate memory-related loads.Timely and tailored reminders for actions like check-ins or self-care activities reduce cognitive burden, aid in memory recall, and encourage adherence to essential health routines.The reminders may also ofer a layer of consistency and reliability that can be comforting for individuals dealing with MH issues.In a landscape where MH conditions can introduce unpredictability and disarray into daily life, the steadiness provided by these persuasive reminders can be a source of stability and reassurance.Leveraging mobile technology not as a replacement but as an amplifcation tool can address this issue.Kentaro et al. proposed that technology tends to amplify existing human forces, enhancing efectiveness where intentions and capabilities are positive, but yielding little or negative impact in areas where human forces are indiferent, dysfunctional, or corrupt [73].In our case, identifying situations where notifcations can prompt actions (Section 5.1), such as motivating check-ins, alerting peer mentees during early crises, or encouraging access to available resources, can amplify existing peer mentor-mentee intervention strategies by reducing the cognitive load on peer mentors.This, in turn, enables them to provide support more efectively and efciently.Furthermore, it's crucial for mentors in peer-mentor support groups to be informed about their mentees' current circumstances, especially considering the vulnerability of individuals with past trauma to crises at any time.Designing warning notifcations for mentors regarding a potential crisis in one of their mentees is based on the fundamental expectation that those who receive such alerts will understand them and take appropriate action, whether by intervening themselves or notifying the relevant authorities.However, decades of social science research suggest that human responses to warnings are intricate [15].Even when an alert is issued and understood, it may not necessarily lead to the intended response, often due to a normalcy bias, where individuals downplay potential danger even when warned [15].Identifying situations where peer mentees can take independent actions through shared well-being resources and prompting them to seek immediate support adds an additional layer of safety, complementing the role of mentors and making peer support interventions more efcient.

CONCLUSION
In this study, we investigated persuasive reminders in peer support with ten US military veterans, emphasizing the signifcance of tailored strategies for efective communication, crisis symptom alerts, and well-being resources.Our fndings highlighted the need for personalized approaches, including success story delivery, motivation understanding, language choice, actionable reminders, and mutual accountability.Designing mental health technologies for and with peer supporters is crucial, especially for veterans who face unique challenges.Trauma experiences impact their seeking and receiving of peer support diferently from civilians.To address the unmet mental health needs of veterans and similar communities, understanding their perceptions of and coping with mental health crises is essential.We provided implications regarding the importance of context-specifc design, elements to reduce cognitive load for peer mentors, and custom user-centered persuasion design for the distinctive needs of military veterans.

Figure 1 :
Figure 1: A broad overview of the timeline involving data collection, analysis, and the formulation of efective persuasive reminders through focus groups and participatory design workshops.

Figure 2 :
Figure 2: Illustrative photos from the participatory design workshops, including one of a peer mentor in a Marine hat writing comments, while other mentors, including LGBTQ+ members, actively participate.The top right image is a scanned sketch by a peer mentor during our workshops.

Figure 3 :
Figure 3: A snapshot from the "Battlepeer" smartphone application displaying concerning check-in results from peer mentees.

Table 1 :
In-depth exploration of fve persuasive reminder scenarios with actual texts and illustrations.

Table 2 :
A brief overview of participants' feedback on fve scenarios and uncovered strategies 5.3.2Strategies for providing encouragement.