SEE MAIN PROJECT WIKI FOR GENERAL INFORMATION ON STUDY BACKGROUND AND DATA COLLECTION **Theoretical Framework** Indigenous peoples face many daily stressors related to colonization, such as discrimination. How Indigenous people perceive themselves relative to such stressors can influence how well they cope. For instance, when people perceive themselves as having resources to cope with the demands of a stressor, a cascade of physiological changes occur that enhance thought and performance, rather than compromise functioning (Blascovich, Mendes, Hunter, & Salomon, 1999). The heart contracts with greater strength and the blood vessels dilate, resulting in more blood, oxygen, and nutrients transferring throughout brain and body. This physiological profile reflects a state of challenge; the context is stressful but personal resources meet or exceed the demands of the stressor, producing a physiological response that enhances active coping. When people lack resources to cope, their bodies work against them. The heart might contract with force, due to stress, but blood vessels constrict, shutting down the flow of nutrients essential for optimal brain and body functioning. This physiological profile reflects a state of threat; the context is stressful but personal resources fall short of the demands of the stressor, producing a physiological response that undermines active coping. Thus, whether Indigenous peoples perceive themselves as having the personal resources to cope with discrimination may impact their ability to cope (Brondolo et al., 2009). A personal resource that might impact whether Indigenous people cope well with discrimination is their ethnic identity. Numerous theoretical perspectives argue that a strong ethnic identity is a resource one may draw upon to cope with discrimination (Branscombe et al., 1999; Phinney, 1990; Seller & Shelton, 2003). In general, empirical evidence confirms this perspective (Yip et al., 2019). Yet, few studies have examined the role of ethnic identity as a buffer of physiological measures of stress reactivity and, to our knowledge, no one has examined ethnic identity as a predictor of challenge and threat. There are many reasons why a strong ethnic identity might predict challenge, not threat, when people confront discrimination. Highly identified people report more exposure to discrimination (Major, 1994; Sellers & Shelton, 2003) and are more motivated to defend their identity (Tajfel & Turner, 1979) than people who reject their identity. Expecting discrimination and feeling motivated to defend one’s identity, highly identified Indigenous people may have well-thought-out responses to future instances of discrimination. A strategy by which to respond to discrimination is a resource and, thus, should evoke challenge. Lacking a response to discrimination should result in threat. Ethnic identification might also promote challenge through increased social support. Relative to people who reject their ethnic identity, highly identified people are more likely to seek support from their ethnic ingroup in response to discrimination (Lopez, Antoni, Fekete, & Penedo, 2012). By seeking social support, highly identified people will learn how other community members cope with discrimination, will surround themselves with people who understand them, and will feel a greater sense of collective self-esteem (Luhtanen & Crocker, 1992). Each of these benefits of group belonging and identity are resources for coping with discrimination and, thus, should encourage challenge. In contrast, people low in ethnic identification may be less likely to perceive these benefits of ethnic group membership because their participation in these communities will be less connected to their experiences of ethnicity. However, it is important to note that seeking support is not always beneficial; in some cases, it may evoke negative feelings and distress, or result in isolation from broader support networks that could provide different perspectives or resources (Brondolo, et al., 2009; Lepore & Revenson, 2007; Utsey et al., 2002). **Primary Hypotheses** Key goals of the proposed work are (1) to determine whether ethnic identification encourages a pattern of physiological arousal reflecting challenge (versus threat) in response to a discrimination-related stressor, (2) to address whether ethnic identification mitigates HPA stress reactivity in response to a discrimination-related stressor, and (3) to identify whether, compared to threat, challenge evoked during a discrimination-related stressor predicts less subsequent rumination and healthier profiles of overall chronic stress. **Hypothesis 1:** Consistent with the broader literature (Phinney, 1992; Sellers et al., 1998; Yip et al., 2019), our primary hypotheses focus on ethnic identity as a multidimensional construct. For instance, the Multiethnic Identity Measure (MEIM-R; Phinney & Ong, 2007)—a measure of ethnic identity used in the current study—is conceptualized as consisting of two related facets: exploration and commitment [see Note 1]. Exploration is marked by a certain level of ambiguity about one's ethnicity or race and involves activities and behaviours aimed at understanding how ethnicity or race shapes one's overall identity (Yip et al., 2019). Commitment involves embracing one's ethnic or racial Identity and having a clear perspective on the significance of ethnicity and race in shaping oneself (Yip et al., 2019). A recent meta-analysis shows that higher levels of ethnic or racial identity exploration can predict poorer psychological adjustment in relation to ethnic discrimination, especially among younger adults. Conversely, commitment predicts better overall psychological adjustment (Yip et al., 2019). Consistent with these findings, in a sample of urban American Indians and Alaska Natives (AI/AN), we anticipate that exploration will predict threat and heightened HPA reactivity whereas commitment will predict challenge [see Note 2] in response to a discrimination-related stressor. To replicate past work, we will also run analyses of ethnic identity as a unidimensional construct. As a unidimensional construct, ethnic identity (measured with the MEIM) typically relates with better health and well-being (Yip et al., 2019). Thus, we anticipate that AI/AN who identify more with their ethnicity and culture (composite measure) will display a physiological profile reflecting challenge during a discrimination-related stressor. Conversely, AI/AN who identify less with their ethnicity and culture will exhibit threat and heightened HPA reactivity. Related to the above, our study also measured ethnic identity using the Bicultural Ethnic Identity Scale (BEIS; Moran et al., 1999). BEIS offers AI/AN opportunities to indicate their involvement in traditions and cultural activities that are part of their broader AI/AN identity. At face value, these items seem similar to the ethnic behavior subscale of the MEIM. Yet initial exploratory factor analysis reveals that these items load on a unique factor, relative to exploration and commitment subscales of the MEIM-R. Thus, we will treat the BEIS as a unique construct and model it separately. We will treat analyses of this scale as exploratory. Additionally, consistent with past meta-analytic findings that the harms of discrimination are especially strong amongst young adults high in exploration (Yip et al., 2019) and in keeping with our own work showing that the association between discrimination exposure and depressive symptoms is greatest amongst young adults (Danyluck et al., 2021), in all models, we will add a second step where we will include age as a moderator of the relationship of ethnic identification with challenge versus threat and HPA axis reactivity. **Hypothesis 2:** AI/AN who display a threat motivational state and heightened HPA axis reactivity during the discrimination-related stress task will have less healthy physiological profiles as reflected in a range of chronic stress measures. Specifically, we anticipate that participants who display patterns of threat will be more likely to display a physiological profile suggesting the presence of metabolic syndrome (MetS; Alberti et al., 2009; Cavero-Redondo et al., 2019). Participants will be classified as having MetS if they have 3 or more of the following measurements: ● Waist circumference of 34.5+ inches for women or 40+ inches for men ● Triglycerides of 150+ mg/dL or on medication to treat hyperlipidemia ● HDL <50 mg/dL for women or <40 mg/dL for men, or taking medication to treat hyperlipidemia (hyperlipidemia medication counted in only 1 category) ● HbA1c >5.7% or self-reported diagnosis of diabetes or taking medication to treat diabetes ● SBP >129 mm Hg or DBP >84 mm Hg or taking medication to treat hypertension We will also explore whether threat and heightened HPA axis reactivity (vs challenge) is a predictor of nocturnal blood pressure in the 24-hour period after the discrimination-related stressor, as well as latent dimensions that might reflect dysregulated activation of the autonomic nervous system (e.g., epinephrine, norepinephrine, 24-hour BP), markers of inflammation (e.g., hs-CRP, TNF-alpha, IL1 beta, IL6, IL10), and anabolic balance (i.e., ratio of dehydroepiandosterone to cortisol). *Notes:* 1. People can be high or low in their achievement of each of these dimensions of identity development, resulting in four possible statuses of identity achievement: diffused, moratorium, foreclosed, and achieved. A diffused ethnic identity belongs to individuals who have neither actively explored their ethnic background nor developed a strong sense of commitment or belonging to their ethnic group. Individuals whose identity is in moratorium are actively exploring and questioning their ethnic identity but may not yet have a strong sense of commitment or belonging to their ethnic group. A foreclosed ethnic identity belongs to individuals who may not have actively explored their ethnic background, but still have a strong sense of belonging and commitment to their ethnic group. Individuals who have actively explored their ethnic background and have a strong sense of belonging and commitment to their ethnic group have achieved their ethnic identity. Thus, whether ethnic identity buffers the harms of discrimination may depend on which status of identity a person has achieved. Yet few studies examine whether these identity achievement statuses differentially buffer people from the harms of ethnic or racial discrimination. To fill this gap, we will run additional, explorations to determine whether differences across ethnic identity achievement status predicts challenge versus threat as well as heightened HPA reactivity. Although largely exploratory, we anticipate that AI/AN with foreclosed and achieved identity status will display challenge, with AI/AN who report achieved identity status displaying the greatest challenge to a discrimination-based stressor. Conversely, we anticipate that AI/AN with moratorium and diffused identity status with display threat and heightened HPA reactivity, with AI/AN who report diffused status displaying the greatest threat and HPA reactivity. 2. Threat is dominated by activity in the HPA axis whereas challenge is dominated by activity in the sympathetic adrenal medullary (Mendes et al., 2007). Given this, and our expectation that people high in ethnic identification will display physiological patterns of challenge, we anticipate HPA axis reactivity will be of lesser magnitude in highly identified people, relative to those low in ethnic identification.