Trait Anxiety Is Associated with Negative Interpretations When Resolving Valence Ambiguity of Surprised Faces

Proposing a model whereby negative valence bias increases the risk for more severe dysphoric posttraumatic stress disorder and depression symptomology

Experiencing trauma increases risk for posttraumatic stress disorder (PTSD) and depression, and individuals who experience psychopathology after a traumatic event often experience symptoms from both disorders. Because a tendency to view events in a more negative light and a propensity toward threat appraisals are risk factors for both PTSD and depression, negative valence bias-a tendency to appraise emotional ambiguity as having a more negative (less positive) meaning-may be a transdiagnostic risk factor. In other words, we expect individuals with a negative valence bias experience greater PTSD and depression symptoms. We measured valence bias and self-reported PTSD and depression symptoms in a sample of college students in 2021 (n = 287; 72.5% reported experiencing trauma). Although valence bias was not associated with PTSD symptoms as a whole, we found in our exploratory model that more negative bias was associated with greater dysphoria-related PTSD symptoms and greater depression symptoms (indirect effect p = .03). Thus, we propose a model whereby a more negative valence bias contributes to increased susceptibility for maladaptive stress responses, which may be associated with greater likelihood of symptoms of dysphoria-related PTSD and depression. These findings suggest that valence bias represents a transdiagnostic affective risk factor, warranting future research examining the impacts of bias-altering interventions (e.g., mindfulness-based treatments) as a means for managing symptoms in individuals with heightened dysphoria-related PTSD and/or depression symptoms. Additionally, in post hoc analyses it emerged that Latinx participants displayed a more negative valence bias, indicating the need for more research in diverse samples. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

Experience-dependent information routing through the basolateral amygdala shapes behavioral outcomes

It is well established that the basolateral amygdala (BLA) is an emotional processing hub that governs a diverse repertoire of behaviors. Selective engagement of a heterogeneous cell population in the BLA is thought to contribute to this flexibility in behavioral outcomes. However, whether this process is impacted by previous experiences that influence emotional processing remains unclear. Here we demonstrate that previous positive (enriched environment [EE]) or negative (chronic unpredictable stress [CUS]) experiences differentially influence the activity of populations of BLA principal neurons projecting to either the nucleus accumbens core or bed nucleus of the stria terminalis. Chemogenetic manipulation of these projection-specific neurons can mimic or occlude the effects of CUS and EE on behavioral outcomes to bidirectionally control avoidance behaviors and stress-induced helplessness. These data demonstrate that previous experiences influence the responsiveness of projection-specific BLA principal neurons, biasing information routing through the BLA, to drive divergent behavioral outcomes.

Associations of state and chronic loneliness with interpretation bias: The role of internalizing symptoms

Loneliness is common and, while generally transient, persists in up to 22% of the population. The rising prevalence and adverse impacts of chronic loneliness highlight the need to understand its underlying mechanisms. Evolutionary models of loneliness suggest that chronically lonely individuals demonstrate negative interpretation biases towards social information. It may also be that such biases are exacerbated by momentary increases in state loneliness, or elevated anxiety or depression. Yet, little research has tested these possibilities. The current study aimed to advance understandings of loneliness by examining associations of chronic loneliness with individual differences in negative interpretation bias for social (relative to non-social) stimuli, and testing whether these associations change in the context of increased state loneliness and current levels of anxiety and depressive symptoms. These aims were explored in 591 participants who completed an interpretation bias task before and after undergoing a state loneliness induction. Participants also self-reported chronic loneliness, anxiety, and depression. Linear mixed models indicated that only state (but not chronic) loneliness was associated with more positive interpretations of non-social stimuli, with greater anxiety and depressive symptoms predicting more negative interpretations. Implications of these findings for present theoretical models of loneliness are discussed.

The role of trait reappraisal in response to emotional ambiguity: A systematic review and meta-analysis

Individuals exhibit a systematic valence bias-a specific form of interpretation bias-in response to emotional ambiguity. Accumulating evidence suggests most people initially respond to emotional ambiguity negatively and differ only in subsequent responses. We hypothesized that trait-level cognitive reappraisal-an emotion regulation strategy involving the reinterpretation of affective meaning of stimuli-might explain individual differences in valence bias. To answer this question, we conducted a random-effects meta-analysis of 14 effect sizes from 13 prior studies (n = 2,086), identified via Google Scholar searches. We excluded studies (a) in languages other than English, (b) from non-peer-reviewed sources, or (c) nonempirical sources. We included studies with (a) the Emotion Regulation Questionnaire, (b) a putative measure of valence bias prior to any study-specific manipulations, and (c) adult human participants (i.e., 17+). Supporting our prediction, we found individuals with higher trait reappraisal exhibited a less negative bias (r = -.18, z = -4.04, p < .001), whereas there was a smaller, opposite effect for trait expressive suppression (r = .10, z = 2.14, p = .03). The effects did, however, vary across tasks with stronger effects observed among studies using the scrambled sentences task compared to the valence bias task. Although trait reappraisal accounted for only a small amount of variance, reappraisal may be one mechanism contributing to variability in response to ambiguity. (PsycInfo Database Record (c) 2024 APA, all rights reserved).

The change of state-trait anxiety among patients undergoing orthognathic surgery: A longitudinal study

INTRODUCTION

This study aimed to assess state-trait anxiety level changes in Chinese patients with dentofacial discrepancies before and after orthognathic surgery and to explore the feasibility of developing a reference index for the preoperative screening of postoperative patients with high anxiety.

METHODS

A total of 96 Chinese patients with dentofacial discrepancies who underwent orthognathic surgery were included in this study. Data were collected before orthognathic surgery and at 2 weeks (T2), 3 months, and 6 months (T4) after surgery using the State-Trait Anxiety Inventory. Receiver operating characteristic and linear regression analyses were performed to screen for preoperative indicators of postoperative high-state anxiety.

RESULTS

State-trait anxiety levels in patients with dentofacial discrepancies decreased after surgery (F = 18.95, P <0.01; F = 6.90, P <0.01). Trait Anxiety Inventory can be used to screen patients with high-state anxiety from T2 to T4 (area under cover 95% confidence interval: T2, 0.74 [0.62-0.86]; 3 months, 0.79 [0.69-0.90]; T4, 0.77 [0.66-0.87], P <0.01), corresponding to cutoff values of 48.5, 46.5, and 45.5, respectively.

CONCLUSIONS

All participants' state-trait anxiety levels improved after surgery compared with their preoperative levels. Preoperative trait anxiety levels can be used as a reference indicator to screen patients who may have high-state anxiety levels after orthognathic surgery. The creation of a screening scale will assist health care professionals to more pertinently help patients with high anxiety.

Reward Sensitivity and Noise Contribute to Negative Affective Bias: A Learning Signal Detection Theory Approach in Decision-Making

In patients with mood disorders, negative affective biases - systematically prioritising and interpreting information negatively - are common. A translational cognitive task testing this bias has shown that depressed patients have a reduced preference for a high reward under ambiguous decision-making conditions. The precise mechanisms underscoring this bias are, however, not yet understood. We therefore developed a set of measures to probe the underlying source of the behavioural bias by testing its relationship to a participant's reward sensitivity, value sensitivity and reward learning rate. One-hundred-forty-eight participants completed three online behavioural tasks: the original ambiguous-cue decision-making task probing negative affective bias, a probabilistic reward learning task probing reward sensitivity and reward learning rate, and a gambling task probing value sensitivity. We modelled the learning task through a dynamic signal detection theory model and the gambling task through an expectation-maximisation prospect theory model. Reward sensitivity from the probabilistic reward task (β = 0.131, p = 0.024) and setting noise from the probabilistic reward task (β = -0.187, p = 0.028) both predicted the affective bias score in a logistic regression. Increased negative affective bias, at least on this specific task, may therefore be driven in part by a combination of reduced sensitivity to rewards and more variable responses.

In the face of ambiguity: intrinsic brain organization in development predicts one's bias toward positivity or negativity

Exacerbated negativity bias, including in responses to ambiguity, represents a common phenotype of internalizing disorders. Individuals differ in their propensity toward positive or negative appraisals of ambiguity. This variability constitutes one's valence bias, a stable construct linked to mental health. Evidence suggests an initial negativity in response to ambiguity that updates via regulatory processes to support a more positive bias. Previous work implicates the amygdala and prefrontal cortex, and regions of the cingulo-opercular system, in this regulatory process. Nonetheless, the neurodevelopmental origins of valence bias remain unclear. The current study tests whether intrinsic brain organization predicts valence bias among 119 children and adolescents (6 to 17 years). Using whole-brain resting-state functional connectivity, a machine-learning model predicted valence bias (r = 0.20, P = 0.03), as did a model restricted to amygdala and cingulo-opercular system features (r = 0.19, P = 0.04). Disrupting connectivity revealed additional intra-system (e.g. fronto-parietal) and inter-system (e.g. amygdala to cingulo-opercular) connectivity important for prediction. The results highlight top-down control systems and bottom-up perceptual processes that influence valence bias in development. Thus, intrinsic brain organization informs the neurodevelopmental origins of valence bias, and directs future work aimed at explicating related internalizing symptomology.

Individual differences in the evaluation of ambiguous visual and auditory threat-related expressions

This study investigated the neural correlates of the judgement of auditory and visual ambiguous threat-related information, and the influence of state anxiety on this process. Healthy subjects were scanned using a fast, high-resolution functional magnetic resonance imaging (fMRI) multiband sequence while they performed a two-alternative forced-choice emotion judgement task on faces and vocal utterances conveying explicit anger or fear, as well as ambiguous ones. Critically, the latter was specific to each subject, obtained through a morphing procedure and selected prior to scanning following a perceptual decision-making task. Behavioural results confirmed a greater task-difficulty for subject-specific ambiguous stimuli and also revealed a judgement bias for visual fear, and, to a lesser extent, for auditory anger. Imaging results showed increased activity in regions of the salience and frontoparietal control networks (FPCNs) and deactivation in areas of the default mode network for ambiguous, relative to explicit, expressions. In contrast, the right amygdala (AMG) responded more strongly to explicit stimuli. Interestingly, its response to the same ambiguous stimulus depended on the subjective judgement of the expression. Finally, we found that behavioural and neural differences between ambiguous and explicit expressions decreased as a function of state anxiety scores. Taken together, our results show that behavioural and brain responses to emotional expressions are determined not only by emotional clarity but also modality and the subjects' subjective perception of the emotion expressed, and that some of these responses are modulated by state anxiety levels.

Synchronized Incidental Affect Changes Ambiguity Preferences

Decisions under uncertainty are prevalent, but come under two distinct types. Risk, which has unknown outcomes but known probabilities for those outcomes and ambiguity which contains both unknown outcomes and unknown probabilities. Although there have been several studies linking affect and aversion to ambiguity, there have been no studies that have to identify how changing one's affective response can change their choices. A total of 166 adults ( M = 36.54, SD = 11.80) participated in an online study through Prolific. Participants were presented with a lottery on each trial which varied on its uncertainty type (risky vs ambiguous) and winning characteristics (winning probability and amount). Half of the ambiguous lotteries were paired with an neutral image (e.g., office supplies), while the other half was paired with an emotionally evocative image (e.g., burning house) that was hypothesized to incidentally influence their decisions. As measured by both raw choice data as well as through a computational model, participants were more averse to ambiguity when the lottery was paired with an emotionally evocative image. Follow-up analyses revealed that only lotteries in which the computational model predicted the participant would choose the lottery were affected by the images. This study highlights the phenomenon in which one's awareness of an affective stimulus can alter its impact on their decisions.

Relationship between types of anxiety and the ability to recognize facial expressions

This study examined whether three subtypes of anxiety (trait anxiety, state anxiety, and social anxiety) have different effects on recognition of facial expressions. One hundred and thirty-eight participants matched facial expressions of three intensity levels (20 %, 40 %, 100 %) with one of the six emotion labels ("happy", "sad", "fear", "angry", "disgust", and "surprise"). While using a conventional method of analysis we were able to replicate some significant correlations between each anxiety type and recognition performance found in the literature. However, when we used partial correlation to isolate the effect of each anxiety type, most of these correlations were no longer significant, apart from the negative correlations between Beck Anxiety Inventory and reaction time to fearful faces displayed at 40 % intensity level, and the correlations between anxiety and categorisation errors. Specifically, social anxiety was positively correlated with misidentifying a happy face as a disgust face at 40 % intensity level, and state anxiety negatively correlated with misidentifying a happy face as a sad face at 20 % intensity level. However, these partial correlation analyses became non-significant after p value adjustment for multiple comparisons. Our eye tracking data also showed that state anxiety may be associated with reduced fixations on the eye regions of low-intensity sad or fearful faces. These analyses cast doubts on some effects reported in the previous studies because they are likely to reflect a mixture of influences from highly correlated anxiety subtypes.

Neural representations of ambiguous affective stimuli and resilience to anxiety in emerging adults

The tendency to interpret ambiguous stimuli as threatening has been associated with a range of anxiety disorders. Responses to ambiguity may be particularly relevant to mental health during the transition from adolescence to adulthood ("emerging adulthood"), when individuals encounter unfamiliar challenges and navigate novel social situations. However, it remains unclear whether neural representations of ambiguity relate to risk for anxiety. The present study sought to examine whether multivariate representations of ambiguity - and their similarity to representations of threat - relate to appraisals of ambiguity or anxiety in a sample of emerging adults. Participants (N = 41) viewed threatening (angry), nonthreatening (happy), and ambiguous (surprised) facial stimuli while undergoing fMRI. Outside of the scanner, participants were presented with the same stimuli and categorized the ambiguous faces as positive or negative. Using representational similarity analyses (RSA), we investigated whether the degree of pattern similarity in responses to ambiguous, nonthreatening, and threatening faces within the amygdala related to appraisals of ambiguous stimuli and anxiety symptomatology. We found that individuals who evidenced greater similarity (i.e., less differentiation) in neural representations of ambiguous and nonthreatening faces within the left amygdala reported lower concurrent anxiety. Additionally, trial-level pattern similarity predicted subsequent appraisals of ambiguous stimuli. These findings provide insight into how neural representations of ambiguity relate to risk or resilience for the development of anxiety.

Research Review: The neuroscience of emerging adulthood - reward, ambiguity, and social support as building blocks of mental health

BACKGROUND

The interval between adolescence and adulthood, 'emerging adulthood' (EA), lays the foundation for lifelong health and well-being. To date, there exist little empirical data - particularly in the neurobiological domain - to establish markers of risk and resilience during the transition to adulthood. This gap in the literature is concerning given the numerous forms of psychiatric illness that emerge or worsen during this period.

METHODS

In this review, we focus on two strands of research with distinct importance for EA: reward sensitivity, and tolerance of ambiguity. We begin by placing these domains in a framework that considers the unique developmental goals of EA and then synthesize emerging neurobiological research on how these domains develop during EA. We then consider their role in common mental health problems that occur during this interval as well as how social support may moderate outcomes. Finally, we offer recommendations for advancing research to understand developmental process and outcomes in EA.

FINDINGS AND CONCLUSIONS

Few longitudinal studies specifically address emerging adult development and the milestones that characterize this interval. Data on neurobiological development are similarly sparse. Understanding neurobiological development during this window and its links to key adjustment outcomes is crucial for optimizing outcomes.

The effect of trait anxiety on the time course of self-relevant processing: Evidence from the perceptual matching task

Studies have widely reported that trait anxiety is associated with a range of cognitive biases toward external negative emotional stimuli. However, few studies have examined whether trait anxiety modulates intrinsic self-relevant processing. This study investigated the electrophysiological mechanism underlying trait anxiety's modulating effect on self-relevant processing. Event-related potentials (ERPs) were recorded while participants performed a perceptual matching task that assigned an arbitrary geometric shape to an association with a "self" or "non-self" label. Results showed larger N1 amplitudes under self-association than under friend-association conditions, and smaller P2 amplitudes for self- than for stranger-association conditions in individuals with high trait anxiety. However, these self-biases in the N1 and P2 stages were not observed in those with low trait anxiety until the later N2 stage, in which the self-association condition provoked smaller N2 amplitudes than the stranger-association condition. In addition, both high and low trait anxiety individuals showed larger P3 amplitudes for the self-association condition than for the friend- and stranger-association conditions. These findings suggest that, although both high and low trait anxiety individuals showed self-bias, high trait anxiety individuals distinguished between self-relevant and non-self-relevant stimuli at an earlier stage, which may reflect hypervigilance to self-relevant stimuli.

Think again: the role of reappraisal in reducing negative valence bias

Stimuli such as surprised faces are ambiguous in that they are associated with both positive and negative outcomes. Interestingly, people differ reliably in whether they evaluate these and other ambiguous stimuli as positive or negative, and we have argued that a positive evaluation relies in part on a biasing of the appraisal processes via reappraisal. To further test this idea, we conducted two studies to evaluate whether increasing the cognitive accessibility of reappraisal through a brief emotion regulation task would lead to an increase in positive evaluations of ambiguity. Supporting this prediction, we demonstrated that cuing reappraisal, but not in three other forms of emotion regulation (Study 1a-d; n = 120), increased positive evaluations of ambiguous faces. In a sign of robustness, we also found that the effect of reappraisal generalised from ambiguous faces to ambiguous scenes (Study 2; n = 34). Collectively, these findings suggest that reappraisal may play a key role in determining responses to ambiguous stimuli. We discuss these findings in the context of affective flexibility, and suggest that valence bias (i.e. the tendency to evaluate ambiguity more positively or negatively) represents a novel approach to measuring implicit emotion regulation.

Cumulative lifetime stressor exposure assessed by the STRAIN predicts economic ambiguity aversion

Uncertainty is inherent in most decisions humans make. Economists distinguish between two types of decision-making under non-certain conditions: those involving risk (i.e., known outcome probabilities) and those that involve ambiguity (i.e., unknown outcome probabilities). Prior research has identified individual differences that explain risk preferences, but little is known about factors associated with ambiguity aversion. Here, we hypothesized that cumulative exposure to major psychosocial stressors over the lifespan might be one factor that predicts individuals’ ambiguity aversion. Across two studies (Study 1: n = 58, M_age = 25.7; Study 2: n = 188, M_age = 39.81), we used a comprehensive lifetime stressor exposure inventory (i.e., the Stress and Adversity Inventory for Adults, or STRAIN) and a standard economic approach to quantify risk and ambiguity preferences. Greater lifetime stressor exposure as measured by the STRAIN, particularly in early life, was associated with higher aversion to ambiguity but not risk preferences.

Uncertainty is a factor in most decisions. Here the authors quantify tolerance for two forms of economic uncertainty—risk and ambiguity—and show that greater lifetime stressor exposure (as assessed by a comprehensive lifetime stressor exposure inventory) was associated with higher aversion to decisions involving ambiguity, but not risk.

Reappraisal-but not Suppression-Tendencies Determine Negativity Bias After Laboratory and Real-World Stress Exposure

Higher reactivity to stress exposure is associated with an increased tendency to appraise ambiguous stimuli as negative. However, it remains unknown whether tendencies to use emotion regulation strategies—such as cognitive reappraisal, which involves altering the meaning or relevance of affective stimuli—can shape individual differences regarding how stress affects perceptions of ambiguity. Here, we examined whether increased reappraisal use is one factor that can determine whether stress exposure induces increased negativity bias. In Study 1, healthy participants (n = 43) rated the valence of emotionally ambiguous (surprised) faces before and after an acute stress or control manipulation and reported reappraisal habits. Increased negativity ratings were milder for stressed individuals that reported more habitual reappraisal use. In Study 2 (n = 97), we extended this investigation to real-world perceived stress before and during the COVID-19 pandemic. We found that reappraisal tendency moderates the relationship between perceived stress and increased negativity bias. Collectively, these findings suggest that the propensity to reappraise determines negativity bias when evaluating ambiguity under stress.

Social connectedness and negative affect uniquely explain individual differences in response to emotional ambiguity

Negativity bias is not only central to mood and anxiety disorders, but can powerfully impact our decision-making across domains (e.g., financial, medical, social). This project builds on previous work examining negativity bias using dual-valence ambiguity. Specifically, although some facial expressions have a relatively clear negative (angry) or positive valence (happy), surprised expressions are interpreted negatively by some and positively by others, providing insight into one's valence bias. Here, we examine putative sources of variability that distinguish individuals with a more negative versus positive valence bias using structural equation modeling. Our model reveals that one's propensity toward negativity (operationalized as temperamental negative affect and internalizing symptomology) predicts valence bias particularly in older adulthood when a more positive bias is generally expected. Further, variability in social connectedness (a propensity to seek out social connections, use those connections to regulate one's own emotions, and be empathic) emerges as a notable and unique predictor of valence bias, likely because these traits help to override an initial, default negativity. We argue that this task represents an important approach to examining variability in affective bias, and can be specifically useful across the lifespan and in populations with internalizing disorders or even subclinical symptomology.

The dynamic process of ambiguous emotion perception

Everyday social interactions hinge on our ability to resolve uncertainty in nonverbal cues. For example, although some facial expressions (e.g. happy, angry) convey a clear affective meaning, others (e.g. surprise) are ambiguous, in that their meaning is determined by the context. Here, we used mouse-tracking to examine the underlying process of resolving uncertainty. Previous work has suggested an initial negativity, in part via faster response times for negative than positive ratings of surprise. We examined valence categorizations of filtered images in order to compare faster (low spatial frequencies; LSF) versus more deliberate processing (high spatial frequencies; HSF). When participants categorised faces as "positive", they first exhibited a partial attraction toward the competing ("negative") response option, and this effect was exacerbated for HSF than LSF faces. Thus, the effect of response conflict due to an initial negativity bias was exaggerated for HSF faces, likely because these images allow for greater deliberation than the LSFs. These results are consistent with the notion that more positive categorizations are characterised by an initial attraction to a default, negative response.

Dissociating Cognitive Processes During Ambiguous Information Processing in Perceptual Decision-Making

Decision-making requires the accumulation of sensory evidence. However, in everyday life, sensory information is often ambiguous and contains decision-irrelevant features. This means that the brain must disambiguate sensory input and extract decision-relevant features. Sensory information processing and decision-making represent two subsequent stages of the perceptual decision-making process. While sensory processing relies on occipito-parietal neuronal activity during the earlier time window, decision-making lasts for a prolonged time, involving parietal and frontal areas. Although perceptual decision-making is being actively studied, its neuronal mechanisms under ambiguous sensory evidence lack detailed consideration. Here, we analyzed the brain activity of subjects accomplishing a perceptual decision-making task involving the classification of ambiguous stimuli. We demonstrated that ambiguity induced high frontal θ-band power for 0.15 s post-stimulus onset, indicating increased reliance on top-down processes, such as expectations and memory. Ambiguous processing also caused high occipito-parietal β-band power for 0.2 s and high fronto-parietal β-power for 0.35–0.42 s post-stimulus onset. We supposed that the former component reflected the disambiguation process while the latter reflected the decision-making phase. Our findings complemented existing knowledge about ambiguous perception by providing additional information regarding the temporal discrepancy between the different cognitive processes during perceptual decision-making.

Neurobiological links between stress and anxiety

Stress and anxiety have intertwined behavioral and neural underpinnings. These commonalities are critical for understanding each state, as well as their mutual interactions. Grasping the mechanisms underlying this bidirectional relationship will have major clinical implications for managing a wide range of psychopathologies. After briefly defining key concepts for the study of stress and anxiety in pre-clinical models, we present circuit, as well as cellular and molecular mechanisms involved in either or both stress and anxiety. First, we review studies on divergent circuits of the basolateral amygdala (BLA) underlying emotional valence processing and anxiety-like behaviors, and how norepinephrine inputs from the locus coeruleus (LC) to the BLA are responsible for acute-stress induced anxiety. We then describe recent studies revealing a new role for mitochondrial function within the nucleus accumbens (NAc), defining individual trait anxiety in rodents, and participating in the link between stress and anxiety. Next, we report findings on the impact of anxiety on reward encoding through alteration of circuit dynamic synchronicity. Finally, we present work unravelling a new role for hypothalamic corticotropin-releasing hormone (CRH) neurons in controlling anxiety-like and stress-induce behaviors. Altogether, the research reviewed here reveals circuits sharing subcortical nodes and underlying the processing of both stress and anxiety. Understanding the neural overlap between these two psychobiological states, might provide alternative strategies to manage disorders such as post-traumatic stress disorder (PTSD).

Cortisol responses enhance negative valence perception for ambiguous facial expressions

Stress exposure elicits a prolonged neuroendocrine response, marked by cortisol release, which can influence important forms of affective decision-making. Identifying how stress reactivity shapes subjective biases in decisions about emotional ambiguity (i.e., valence bias) provides insight into the role stress plays in basic affective processing for healthy and clinical populations alike. Here, we sought to examine how stress reactivity affects valence decisions about emotional ambiguity. Given that stress prioritizes automatic emotional processing which, in the context of valence bias, is associated with increased negativity, we tested how individual differences in acute stress responses influence valence bias and how this decision process evolves over time. Participants provided baseline ratings of clear (happy, angry) and ambiguous (surprised) facial expressions, then re-rated similar stimuli after undergoing an acute stress or control manipulation a week later; salivary cortisol was measured throughout to assay stress reactivity. Elevations in cortisol were associated with more negative ratings of surprised faces, and with more direct response trajectories toward negative ratings (i.e., less response competition). These effects were selectively driven by the stress group, evidencing that increased stress reactivity is associated with a stronger negativity bias during ambiguous affective decision-making.