From bystanders to allies: a narrative review of witnessing age discrimination in age-diverse workplaces Free

The global phenomenon of population aging continues due to rising life expectancy, falling fertility rates, and improved mortality conditions. According to the United Nations, there are now 962 million people in the world who are 60 or older. By 2030, the number of people who are 50 or older is expected to rise from 37% to 45% (OECD, 2019). These changes in demographics have a direct effect on labor markets (OECD, 2017), leading to workplaces with people of all ages where diversity is becoming more important as technology changes and the makeup of the workforce changes.

In the past, organizations operated in linear hierarchies, with senior staff members mentoring junior employees (Lyons et al., 2012). These traditional structures are changing, though, as younger professionals take on leadership roles earlier due to increased educational opportunities and technological advancement (Cappelli and Novelli, 2010). Intergenerational conflict is frequently sparked by the significant differences in work approaches, communication styles, and competence perceptions brought about by this evolution (Dencker et al., 2007; Urick et al., 2017). While empirical evidence for generational differences is inconsistent (Costanza et al., 2012; Twenge et al., 2010), this age diversity creates important contexts for analyzing age-related dynamics.

This challenge of managing age-based divisions represents a pivotal turning point where organizational responses determine whether age diversity becomes an asset or liability. When effectively leveraged, multigenerational workforces provide substantial advantages through knowledge exchange and diverse thinking (Burmeister et al., 2020; Zacher et al., 2018). Organizations successfully integrating generational expertise demonstrate enhanced problem-solving capabilities, creativity, and market adaptability (Ellwart et al., 2013; Joshi et al., 2011). Conversely, research indicates that unmanaged age-based categorization damages workplace climate and performance outcomes (Kunze et al., 2011), while homogeneous teams forfeit the productivity and financial benefits diversity offers (Richard and Shelor, 2002). Age segregation creates barriers to knowledge transfer and collaboration, ultimately undermining the competitive advantages age diversity could otherwise provide (Burmeister et al., 2021; North and Fiske, 2015). OECD findings confirm that age-diverse teams outperform homogeneous groups through complementary skills and knowledge exchange (OECD, 2020).

Addressing age bias in the workplace is crucial, as evidenced by some of the Sustainable Development Goals (SDGs) set forth by the UN. Consider SDG 8, which focuses on ensuring that everyone has access to respectable employment, equitable compensation, and secure working conditions. The next goal is SDG 10, which is to reduce inequality and make the world more inclusive for people of all ages (United Nations, 2015). Accepting people of all ages at work is not only the right thing to do, but it's also a smart move, especially as our population ages and the workforce evolves. It's also a powerful way to promote economic growth and build a community where everyone is valued and included.

Ashforth and Anand (2003) highlight how organizations may unintentionally reinforce societal prejudice. Diversity training and formal policies are essential, yet frequently inadequate in preventing discrimination (Paluck, 2006; Roberson et al., 2003). Recent research underscores the social-cognitive mechanisms—especially observation and modeling—that perpetuate bias within organizations (Bandura, 1999; Ferguson et al., 2019). Social cognitive theory emphasizes the process through which individuals acquire knowledge by observing others, highlighting the pivotal role of witnesses in either perpetuating or contesting discriminatory norms (Bandura, 1986; Brown et al., 2005). Organizational psychology has transitioned from an emphasis on victims and perpetrators to an acknowledgment of the impact of bystanders on workplace norms (Ashburn-Nardo et al., 2008; Dickter et al., 2012). Research indicates that witnesses can both reinforce and disrupt bias (Chaudoir and Quinn, 2010; O'Reilly and Aquino, 2011). This paper investigates the impact of witnessing ageism on observers, especially regarding age group allegiance, and advocates for a more profound analysis of the psychological mechanisms influencing bystander interventions (Good et al., 2012; Moisuc et al., 2018). Cortina et al. (2018) further promote a social-ecological perspective, contending that discrimination functions within intricate systems influenced by observer.

Figure 1 shows how ageism spreads in a self-reinforcing cycle through social learning in groups. The model has four main steps: witnessing age-based discrimination, modeling what you observe, rendering the bias normal and acting on it, and finally observing the conduct again and accepting it as normal. Bystanders often play a bigger role than victims or offenders when it comes to either reinforcing or challenging discriminatory norms in workplace culture. Depending on how people respond, these moments can either fuel the spread of ageism or help build a more inclusive environment for people of all ages. This framework goes beyond the typical focus on just victims and offenders by highlighting how witnesses shape what is deemed acceptable at work.

Although age-diverse workplaces are becoming more common, little is known about the effects on bystander employees of witnessing age discrimination. By investigating the psychological processes that connect observed ageism to age group allegiance, with an emphasis on the moderating influence of age diversity climate, this study seeks to close this gap. In particular, we pose the following question: (1) How does witnessing ageism influence age group allegiance among employees? (2) What is the role of negative affect in mediating this relationship? (3) How does age diversity climate moderate the impact of witnessed ageism on age group allegiance?

This study uses a narrative literature review approach to investigate how social learning fuels ageism and inform practical solutions (Green et al., 2006). A narrative literature review facilitates conceptual development and allows for objective synthesis (Onwuegbuzie and Frels, 2016).

Literature on workplace ageism and social cognitive theory was reviewed by searching databases such as Scopus, Web of Science, and Google Scholar using terms like “bystander effect,” “age discrimination,” “intergenerational conflict,” and “diversity climate” in Scopus, Web of Science, and Google Scholar, with a focus on management and psychology disciplines.

Given the relatively early stage of research in this area, studies were included regardless of methodology or publication date, provided they offered insights relevant to the proposed relationship. The following sections present key findings from this review. Using a social cognitive lens, our model clarifies how witnessed discrimination fuels age-based divides—and how organizations might disrupt this cycle.

In order to compile the body of knowledge and create a conceptual framework for investigating observed ageism in age-diverse workplaces, this study used a narrative literature review. According to Green et al. (2006) and Onwuegbuzie and Frels (2016), narrative reviews are especially well-suited for new research fields where the objective is theory development and proposition generation rather than hypothesis testing or effect size estimation. This method supported the creation of testable hypotheses for further empirical research while allowing for flexible integration across various theoretical and empirical literature, which was necessary given the paucity of direct research on observer responses to age discrimination.

We performed systematic searches in three major databases: Web of Science, Scopus, and Google Scholar. The following terms and Boolean combinations were used in the search strategy: “age discrimination,” “ageism,” “bystander effects,” “witnessed discrimination,” “social identity,” “age diversity climate,” “intergenerational workplace conflict,” “organizational age bias,” and “ageism.” Since research on witnessed ageism is still in its infancy, there were no date restrictions. Forward citation searching of seminal works and backward citation tracking from important papers were used to find additional studies.

Search terms unique to a database:

1. Google Scholar: “age discrimination” workplace; “ageism” organizational behavior; “bystander effect” discrimination

2. Scopus: TITLE-ABS-KEY((“age discrimination” OR “ageism”) AND (“workplace” OR “organization*”))

3. Web of Science: TS=((“witnessed discrimination” OR “bystander*”) AND (“age*” OR “intergenerational”))

Inclusion criteria. Studies were included if they: (1) examined age-related bias, discrimination, or stereotyping in workplace contexts; (2) investigated bystander/witness responses to any form of workplace discrimination; (3) provided theoretical frameworks addressing social identity, group processes, or organizational climate relevant to age categorization; (4) were published in English in peer-reviewed outlets; (5) offered insights relevant to understanding how witnessed ageism influences observer responses.

Exclusion criteria: Studies were excluded if they: (1) focused exclusively on hiring/recruitment without ongoing workplace dynamics; (2) were conducted in non-organizational settings; (3) examined age demographics without discrimination or bias components; (4) were non-peer-reviewed sources (note: a small number of policy reports and methodological references are cited for practical contextualization but were not included in the theoretical synthesis count).

Initial database searches yielded approximately 180 sources. After removing duplicates (n = 85) and conducting title/abstract screening against inclusion criteria, 95 sources remained for full-text evaluation. 32 sources were eliminated after a thorough evaluation: 12 only addressed hiring and recruitment without considering ongoing workplace dynamics; 8 looked at age demographics without considering bias or discrimination; 6 were conducted outside of organizations; 4 were not peer-reviewed and lacked theoretical foundations; and 2 looked at general discrimination without considering age. As a result, the theoretical model is directly informed by 63 peer-reviewed studies. When choosing and classifying sources, both authors independently reviewed them; disagreements were settled and consistency was ensured through frequent discussion. Based on their main theoretical contribution, the 63 peer-reviewed studies were systematically divided into five research domains (see Appendix A for the detailed study characteristics): (1) ageism/discrimination (n = 15), (2) bystander/witnessing behavior (n = 7), (3) social identity/group processes (n = 16), (4) organizational climate/diversity (n = 10), and (5) intergenerational/age diversity (n = 15). The synthesis by domain is shown in Table 1, and the selection procedure is depicted in Figure 2.

Note: Literature categorization was conducted through iterative discussion between both authors to ensure consistency. While formal inter-rater reliability statistics were not calculated, both authors reviewed all studies and resolved any categorization disagreements through consensus.

Several factors led to the selection of the narrative review methodology: Because witnessed ageism has received little direct empirical attention, it has been necessary to integrate it across related but distinct literature; (2) our goal was to develop conceptual models with testable propositions rather than to aggregate meta-analytic findings; (3) the topic's interdisciplinary nature necessitated synthesis across the domains of social psychology, organizational psychology, and management; and (4) the field's emerging state made traditional systematic review protocols less appropriate due to heterogeneous methodologies and the need for flexible theoretical integration to identify novel mechanisms and relationships not previously explored. Furthermore, our objective was to create a theoretically integrated model that identifies an uncertainty-based psychological mechanism—the uncertainty-driven allegiance pathway—not previously identified in the literature on age discrimination, rather than to compile effect sizes or map all available evidence in a methodical manner. Instead of systematically aggregating evidence, this conceptual contribution necessitated interpretive synthesis across disparate literature. Our synthesis count of 63 peer-reviewed studies that inform the theoretical model does not include the policy reports (e.g. OECD workforce statistics) and methodological texts that we cite to contextualize practical relevance and justify our approach (n = 6).

This study integrates social information processing theory (Salancik and Pfeffer, 1978), social identity theory (Tajfel and Turner, 1979), and uncertainty-identity theory (Hogg, 2007) to examine how witnessing subtle ageism affects employees' affective responses and behavioral shifts toward same-age interactions.

According to the social information processing theory, workers rely on their surroundings, particularly when things are ambiguous (Salancik and Pfeffer, 1978). Employees use peer behavior as a primary referent when management gives them unclear signals regarding age diversity (Zohar and Luria, 2010). Peer-generated cues are more salient when organizational norms are unclear (Salancik and Pfeffer, 1978).

Social identity theory posits that individuals uphold favorable ingroup identities and delineate themselves through their associations with specific groups (Tajfel and Turner, 1979). Brewer (1999) demonstrates that ingroup favoritism primarily signifies a yearning for inclusion and belonging rather than outgroup animosity, characterizing this phenomenon as “ingroup love” in contrast to “outgroup hate.” People demonstrate ingroup alignment when age boundaries are salient, as evidenced by their preferences for collaboration and the formation of friendships. This preference is driven more by the desire for comfort and the reduction of uncertainty than by animosity towards colleagues of varying ages (Brewer, 1999). This distinction is essential for comprehending observed ageism: observers may empathize with older workers facing discrimination while concurrently seeking psychological safety from peers of the same age, thus perpetuating age-based divisions without overt bias.

Uncertainty-identity theory (Hogg, 2007) links these perspectives by positing that ambiguous contexts heighten dependence on group affiliation for cognitive clarity. Employees favor interactions with peers of similar age due to the greater predictability of social norms and reduced ambiguity in the absence of explicit frameworks for interpreting subtle ageism (Hogg and Mullin, 1999). Rather than being a deliberate exclusion, this preference is a coping mechanism.

Using the affective events theory (Weiss and Cropanzano, 1996), we combine these theories and propose that negative affect resulting from observing subtle ageism is a sign of environmental ambiguity. These emotions cause workers to gravitate toward coworkers of the same age in an effort to engage with interactions with more explicit age-based norms (Hogg, 2007). The primary mechanism that connects observed ageism to behavioral reactions is emotion.

Our model proposes that (1) witnessing subtle ageism relates to stronger age-based interaction preferences, mediated by negative affect, and (2) an uncertain age diversity climate amplifies this relationship by intensifying the affective reaction. By centering uncertainty reduction and affective mechanisms, this framework illuminates how and when observed subtle ageism spreads through emotional pathways, eliciting same-age alignment.

Because they experience more normative ambiguity and may be protected from uncertainty by age-based cohesion, we concentrate on younger employees who witness ageism against their older coworkers (Hogg and Mullin, 1999). A subtle behavioral shift toward same-age interactions that sustains age-based silos without being overtly discriminatory is what witnessing does as a contagion mechanism. Finding this complex route provides opportunities for managerial action.

In this section, we examine the proposed relationships and mechanisms linking witnessed ageism to age group allegiance, with negative affective reactions as a mediator and age diversity climate as a moderator. Witnessed ageism, defined as the observation of age-discriminatory behaviors, is posited to influence age group allegiance, which refers to the preferential treatment and support towards one's own age group. Negative affective reactions, characterized by unpleasant emotional responses to witnessed ageism, are proposed to mediate this relationship. Age diversity climate, reflecting the clarity and consistency of management's age-inclusive practices, is suggested to moderate the impact of witnessed ageism on age group allegiance through its influence on negative affective reactions.

Age group allegiance emerges through social identity processes (Tajfel and Turner, 1986; Hogg et al., 2017) and can persist even when individuals empathize with discriminated outgroups. This apparent paradox—simultaneous empathy and allegiance—reflects what Brewer (1999) identifies as the fundamental distinction between ingroup favoritism and outgroup derogation. Ingroup favoritism operates through positive attachment seeking rather than negative outgroup attitudes. Young workers may witness ageism and feel empathy yet still identify with their cohort—a phenomenon Brewer (1999) explains through the independence of ingroup attachment from outgroup evaluation. Because age group allegiance operates through belonging needs and uncertainty reduction rather than outgroup hostility, individuals can simultaneously (1) recognize discrimination as unjust, (2) feel empathy for victims, and (3) increase same-age clustering without experiencing cognitive dissonance (Brewer, 1999). This makes the contagion of ageism particularly insidious: it spreads through seemingly benign comfort-seeking rather than overt prejudice, rendering it invisible to perpetrators. Ageism manifests through behaviors, attitudes, and stereotypes that deepen workplace divides (Finkelstein et al., 2015), while perceptions of resource competition may sustain younger workers' group loyalty despite empathy (North and Fiske, 2012). Further research is needed to clarify how witnessing discrimination shapes age group allegiance in organizations. In the context of witnessed ageism, age group allegiance may manifest as younger employees increasingly gravitating towards their same-age peers for collaboration, advice-seeking, and social support. To understand how witnessed ageism contributes to age group allegiance, we examine four prominent forms of ageism—each shaping observer responses in unique ways.

Competence-Based Ageism. Competence-based ageism portrays older workers as resistant to change, slow learners, or lacking technical skills (Posthuma and Campion, 2009), leading to reduced idea sharing and increased withdrawal (Finkelstein et al., 2019; von Hippel et al., 2019). Witnessing such bias activates age as a key social category for younger employees, prompting stronger allegiance with their age group over the organization (Abrams et al., 2016; Turner et al., 1987). It reinforces perceived competence gaps and promotes sorting by age, not ability (Kooij et al., 2013; Homan et al., 2007). This strengthens age group allegiance, as individuals seek self-worth through favorable ingroup comparisons (Hornsey, 2008; Hogg, 2016).

Adaptability-Based Ageism. Age-based stereotypes portray older workers as resistant to change, technology-averse, and inflexible (Ng and Feldman, 2012), reinforcing assumptions about their inability to adapt. When younger employees witness such ageism, it strengthens age group allegiance by emphasizing generational differences in adaptability and innovation (North and Fiske, 2016; McGuire et al., 2007). These stereotypes often invoke generational narratives over individual traits (Lyons and Kuron, 2014), prompting younger workers to view workplace interactions through a generational lens (Joshi et al., 2011). Fearing similar treatment as they age, they experience identity threat and respond by aligning more closely with their age peers while distancing from older colleagues (Finkelstein et al., 2019; Weiss and Lang, 2012; Garstka et al., 2004).

Socio-Emotional Ageism. Ageism often involves socio-emotional stereotypes portraying older workers as difficult, overly sensitive, or uncooperative, emphasizing personality over ability (Posthuma and Campion, 2009). These stereotypes create perceived communication and value mismatches, prompting younger employees to favor interactions with peers. Witnessing older colleagues as unapproachable or sensitive leads to expectations of communication difficulties (McCann and Giles, 2006), while perceived value differences reinforce psychological distance (Burke et al., 2015; Lyons et al., 2012). Such stereotyping fosters exclusionary behaviors, where younger workers observe and replicate age-segregated interaction norms through social learning (Bandura, 1977).

Resource-Based Ageism. Resource-based ageism involves beliefs that older employees contribute less while consuming more organizational resources (North and Fiske, 2013). This includes assumptions that they block advancement, monopolize opportunities, and are overcompensated (North and Fiske, 2016). Witnessing such bias highlights intergenerational competition for limited resources like promotions and training, making age group membership more salient. In response, younger workers show defensive ingroup favoritism, aligning with peers to safeguard their interests and reinforcing age as a key workplace category.

According to social identity theory (Tajfel and Turner, 1986) and self-categorization theory (Turner et al., 1987), individuals develop a sense of self based on their group affiliations, particularly when group boundaries are highlighted by instances of unequal or biased treatment. These theories suggest that witnessing differential treatment based on a social category (like age) heightens that category's salience as a meaningful social distinction. This increased salience leads individuals to define themselves more strongly through their category membership and engage in social comparison that emphasizes intergroup differences. Age group allegiance results from these processes, strengthening ingroup allegiance while establishing psychological distance from outgroups (Brewer, 1999; Hogg, 2016). We suggest that observed age discrimination fosters age group allegiance through the effects of various forms of ageism on observer categorization processes, leading to our first proposition:

Understanding how witnessed ageism triggers emotional responses and strengthens age group allegiance is essential. Social Information Processing Theory (Salancik and Pfeffer, 1978) explains that people interpret workplace events through cognitive and affective cues, with affect playing a key role in shaping intergroup behavior (Mackie et al., 2000; van den Bos, 2003). Witnessed discrimination often leads to negative emotions (Chaudoir and Quinn, 2010), which reflect psychological discomfort from norm violations (Cooper, 2007). Factors like intent ambiguity and organizational climate affect the intensity of these reactions (O'Reilly and Aquino, 2011). For younger employees, this discomfort arises in several ways: witnessing ageism creates uncertainty between organizational and age-group norms (Ashforth and Anand, 2003), threatens moral identity when the perpetrator is an ingroup member (Bandura, 1999), and fosters moral disengagement, which increases age group allegiance (Leidner et al., 2010). It also triggers status insecurity (North and Fiske, 2015), encouraging peer alignment as a coping mechanism. Uncertainty-identity theory (Hogg, 2007) supports this, suggesting that uncertainty drives stronger identification with salient social groups (Reid and Hogg, 2005). As no prior work has examined this link, we propose negative affect mediates the relationship between witnessed ageism and age group allegiance.

Organizational context strongly shapes how employees respond to witnessed ageism. We propose that age diversity climate—employees’ perceptions of how much leadership values age differences (Boehm et al., 2014; Kunze et al., 2011)—moderates the link between observed ageism, negative affect, and age group allegiance. When management is unclear or dismissive about age inclusivity, it creates normative ambiguity, heightening discomfort and leading employees to rely more on peer cues (Zohar, 2000; Salancik and Pfeffer, 1978). This amplifies the emotional impact of witnessed discrimination and strengthens age group allegiance (Robinson and O'Leary-Kelly, 1998). In contrast, clear signals that leaders support inclusivity help employees view ageism as deviant, prompting more constructive responses (McKay et al., 2008). Uncertainty management theory suggests unclear norms increase identity-driven coping, reinforcing age group allegiance (Hogg and Mullin, 1999). Moreover, organizational tolerance for age bias legitimizes ingroup favoritism via moral credentialing (Monin and Miller, 2001), allowing negative affect to fuel allegiance with age peers (Kouchaki, 2011). Thus, drawing on social information processing and uncertainty management theories, we argue that age diversity climate moderates how witnessed ageism influences age group allegiance through negative affect.

Knowing how ageism spreads socially has become essential to resolving intergenerational conflicts amid the historic demographic changes transforming today's workplaces and the serious difficulties presented by growing age diversity. Facilitating the ability of employees to navigate age-diverse environments and sustain fruitful cross-generational relationships is a critical role of organizational behavior and human resource management. In this paper, we propose a model that investigates the effects of observing age-based discrimination on the reactions of observers. We emphasized how, rather than inspiring anti-discrimination action, observed ageism can elicit negative affective responses that paradoxically increase age group allegiance. The age diversity climate of the organization also affects this relationship and has the potential to either increase or decrease these effects. The theoretical and practical implications of our model are discussed in the sections that follow, with an emphasis on how it might help promote age-inclusive cultures and recede the spread of discriminatory norms through social observation.

This paper advances organizational discrimination research by adopting an interdisciplinary perspective and spotlighting how observed ageism influences observers through distinct psychological pathways. Even though there is a growing interest in bias at work, we don't know much about how witnessing age discrimination affects the attitudes and actions of third parties. This is problematic because it renders it more challenging to understand how bias spreads through social structures. To fill this gap, our conceptual model introduces witness-centered mechanisms that explain age-based division. It does this by using theories from social information processing, social identity, and uncertainty management. This integrated model builds on other models by looking at how discrimination spreads beyond its direct targets from cognitive, emotional, and identity-based points of view. One important theoretical advance is to think about age group allegiance in terms of Brewer's (1999) ingroup love framework instead of outgroup hostility models. This difference shows why age-based divisions still exist, even among employees who care about their coworkers who are being discriminated against: the mechanism works through belonging needs that are based on uncertainty rather than prejudice. So, traditional discrimination interventions that focus on changing hostile attitudes may not work when the underlying dynamic is based on needs for comfort and mental clarity. This novel way to conceptualize has significant implications on how to design interventions. It suggests that making elements less ambiguous by having clear organizational norms may be better than traditional ways of reducing prejudice.

The paper proposes significant advances in the theories of uncertainty-identity (Hogg, 2007) and social information processing (Salancik and Pfeffer, 1978). The latter explains how people use social cues to figure out how to respond, which supports our claim that discrimination affects how people perceive age-related norms. Clear normative expectations set by inclusive leaders are necessary for effective management of age diversity. In this theoretical path, negative affect becomes a key mediator, which is in line with uncertainty-identity theory to explain how people respond to ageism when they witness it.

Integrating these theories clarifies how observation can prompt identity-protective rather than corrective reactions. We propose that examining links between witnessed ageism, negative affect, age group allegiance, and the moderating role of age diversity climate can enhance understanding of how discrimination spreads and persists within organizations.

Organizations often overlook the influence of social dynamics on discriminatory norms by focusing solely on formal policies. According to a witness-centered view, witnesses are very important in either supporting or opposing discrimination. This shows how bias spreads through observation. The prevalence of peer-based ageism and the clarity of age diversity norms differ across workplaces. Some people don't have inclusive norms even though their peers don't show bias, while others face subtle discrimination when leadership signals are unclear. The most favorable environments have strong support for including people of all ages and minimal discrimination.

Diversity training that is focused can help with these differences. Strong organizational norms help bystander interventions work better by making it easier for people to get over their feelings (Good et al., 2012; Moisuc et al., 2018). Controlling negative emotions is crucial, as they can exacerbate anxiety, perpetuate stereotypes, and diminish interest (Chaudoir and Quinn, 2010; Weiss and Cropanzano, 1996). Role modeling and inclusive leadership, both of which are based on social learning, can help people give constructive witness responses. As the age gap widens, intergenerational relationships become increasingly vital for knowledge dissemination and collaboration. They may cause adverse outcomes if not handled well. Organizations should look at how their peers interact with each other and how diverse their workplace is to come up with focused strategies that don't rely on age-based fault lines. As the younger generation joins the workforce and Boomers stay in it, the differences between the two generations in how they expect things to be, use technology, and communicate grow. When norms are not clear, they can cause people to split up and form silos. When norms are clear, people can use them to their advantage.

Such contexts can lead to defensive age-based identities over shared organizational goals (Kunze and Boehm, 2013; North and Fiske, 2016). Addressing how witnessed ageism fuels these divides—and the mechanisms sustaining them—can reduce fragmentation and promote collaboration across age groups.

The study's findings have significant implications for achieving the Sustainable Development Goals of the UN, particularly SDGs 8 (Decent Work and Economic Growth) and 10 (Reduced Inequalities). By understanding how observed ageism perpetuates age-based divisions, organizations can better align their practices with these global commitments. The proposed framework offers helpful guidance on creating safe and equitable work environments for all employees, regardless of age. Everyone gains from this, and it helps society grow in a constructive way.

This study offers a witness-centered framework to understand and address age-based discrimination, paving the way for additional research and subsequent diversity program initiatives. Discrimination is shaped by coworker interactions and the organizational context; further research should investigate factors such as moral disengagement, observer characteristics (including moral identity and empathy), team climate, and the evolution of work structures (such as remote versus co-located environments). Our model incorporates personal factors, including negative emotions and loyalty to a particular age group, alongside organizational factors, such as a age diversity climate, that affect witness behavior. Future research might investigate the influence of hierarchy and power dynamics on responses to ageism and expand the model to include reverse ageism, especially the reactions of older employees to discrimination against younger workers. Furthermore, alternative mediators such as empathy and perceived similarity, along with moderators including job security, ethical leadership, and organizational identification, may augment the model's complexity. Finally, as the proposed set of relationship is based on Western literature, cross-cultural research is needed to capture variations in age-related norms across global contexts.

Testing the uncertainty-driven allegiance model requires specific research designs:

Experimental studies should manipulate normative clarity (clear vs. ambiguous management signals) and measure uncertainty-specific emotions (confusion, ambiguity discomfort) alongside general negative affect to isolate the uncertainty mechanism from alternative affective pathways (moral outrage, empathy, threat).

Experience sampling methods could capture real-time affective responses to witnessed discrimination in natural settings, testing whether uncertainty emotions predict subsequent same-age interaction patterns more strongly than other negative emotions.

Longitudinal field studies tracking employees across climate changes would test whether clarity interventions reduce the witnessed ageism–allegiance relationship by providing interpretive frameworks, as our model predicts.

Cross-cultural comparative studies should examine whether uncertainty-driven allegiance operates differently in high vs. low uncertainty avoidance cultures, testing boundary conditions of the proposed mechanism.

While we propose uncertainty-driven allegiance as the explanatory mechanism, we acknowledge that negative affect may reflect various appraisals: interpretive discomfort from normative ambiguity, moral unease, threat perception, or empathic distress. Our conceptual model prioritizes the uncertainty interpretation because it best explains why (1) age diversity climate moderates the relationship, and (2) affect channels toward age group allegiance rather than intervention. However, empirical validation requires distinguishing uncertainty-specific emotions from general negative affect—a measurement precision our narrative synthesis cannot provide but which experimental studies should address.

While our model focuses on younger workers witnessing ageism against older colleagues, future research could explore boundary conditions and alternative pathways. For instance, the model may operate differently when older workers witness ageism against younger colleagues. Additionally, in some cases, witnessed ageism may evoke moral outrage that leads to cross-age solidarity rather than increased age group allegiance. Examining these boundary conditions and alternative pathways would provide a more comprehensive understanding of the complex dynamics of witnessed ageism in the workplace.

Organizations and HR stakeholders need not view age diversity as an inevitable source of conflict but as an opportunity to foster inclusive environments where intergenerational collaboration can flourish. The proposed model integrates overlooked connections and connects research on discrimination—typically centered on targets and perpetrators—with wider organizational factors that influence the development of discriminatory norms. By describing how observed discrimination contributes to the establishment and maintenance of age-based divisions, we outline a practical remedy for several undesirable and preventable outcomes. Through various theories, we support the moderating role of age diversity climate and the mediating role of negative affect in understanding the social propagation of ageism. The conceptual model presented in this paper encourages further research, especially on developing successful interventions to stop the social transmission of discriminatory norms and promote workplaces that are truly inclusive of all ages. This study gives us useful information on how to deal with one of the most common but least talked about forms of workplace discrimination. Organizations all over the world are working hard to meet the UN Sustainable Development Goals, especially those that have to do with decent work and less inequality.

The supplementary material for this article can be found online.