About

Wendy Berry Mendes is the Chris Argyris Professor of Psychology at Yale University. She earned her PhD in 2003 from UC Santa Barbara. Her research focuses on how the brain and body respond to emotion and stress states, utilizing approaches such as autonomic nervous system physiology, neuroendocrinology, and facial EMG. Her recent work examines the influence of emotion on decision-making, the effects of discrimination and stigmatization on physical and mental health, and how dyads and groups influence each other through affect contagion. Additionally, her research explores how stress impacts physiology and cognition across the lifespan. She approaches these questions in various contexts, including laboratory settings, daily life, and field environments such as classrooms and operating rooms. Her primary goal is to better understand the bidirectional influences of the mind and body from a social psychological perspective.

Research topics

• Psychology
• Sociology
• Medicine
• Social psychology
• Gerontology
• Statistics
• Ecology
• Developmental psychology
• Demography
• Biology

Selected publications

• Beyond the mean: Sequence analysis methods for clustering ordinal EMA data

  ArXiv.org · 2026-04-26

  articleOpen access

  Ecological momentary assessment (EMA) ratings are widely used in studies of behavioral and psychological phenomena to capture real-time data in subjects' real-world environments. Because the data are collected repeatedly over the study period, they provide rich longitudinal rating profiles for each individual. However, the number of observations per subject is often large, while both sample size and sampling intensity can vary substantially across individuals, which complicates the analysis. In some settings, simplified summaries of individual profiles, such as averages computed across the study period, are used for downstream analyses, including regression-style modeling. Although such summaries can be convenient, they may fail to fully capture dynamic temporal patterns present in the complete longitudinal profiles. To address this, we borrow measures from sequence analysis that capture individual-level patterns over time and then applied principal component analysis (PCA) followed by $K$-means clustering to identify unobserved latent groups of individuals with similar profiles. We test our approach using simulated data from a categorical functional regression model and compare its performance with two commonly used methods for detecting unobserved group structures: latent class analysis (LCA), and latent transition analysis (LTA). Using EMA stress observations from a large sample of U.S. adults (Newman et al., 2024, 2025), we identify distinct latent stress profile groups and show that they improve characterization of the impact on cognitive performance.

  PublisherOA PDF

• Social Threat and Childhood Security

  OSF Preprints (OSF Preprints) · 2026-02-27

  other1st authorCorresponding
  Publisher

• The effects of transcutaneous vagus nerve stimulation on romantic couples’ physiology and behavior during conflict

  Anxiety Stress & Coping · 2026-01-04

  articleSenior author

  BACKGROUND: Conflicts with close others and subsequent affective reactions can have long-term consequences for mental and physical health. Building on recent studies using transcutaneous vagus nerve stimulation (tVNS) highlighting the role of the vagus nerve in social functioning, we examined if tVNS can modulate the emotional, physiological, and behavioral responses to a romantic conflict. METHODS: 134) were randomly assigned to tVNS or sham stimulation. Both partners received continuous tVNS or sham stimulation for 15 min before and during a six-minute discussion about a recurring conflict topic. We examined each partner's emotional and respiratory sinus arrhythmia (RSA) reactivity to conflict and the partners' physiological and behavioral attunement to each other. RESULTS: Our results revealed no condition differences in emotional experiences, but individuals receiving tVNS (vs. sham stimulation) experienced greater decreases in RSA during conflict. Further, while RSA reactivity synchrony did not differ between conditions, couples in the tVNS (vs. sham stimulation) condition showed greater behavioral synchrony. CONCLUSIONS: This work provides experimental evidence supporting the role of the vagus nerve in modulating reactions to stressful social interactions, highlighting the potential of tVNS to subtly influence couple dynamics at physiological and behavioral levels.

  PublisherDOI

• Race, Emotion Regulation and BP

  OSF Preprints (OSF Preprints) · 2026-02-18

  other
  Publisher

• Beyond the mean: Sequence analysis methods for clustering ordinal EMA data

  arXiv (Cornell University) · 2026-04-26

  preprintOpen access

  Ecological momentary assessment (EMA) ratings are widely used in studies of behavioral and psychological phenomena to capture real-time data in subjects' real-world environments. Because the data are collected repeatedly over the study period, they provide rich longitudinal rating profiles for each individual. However, the number of observations per subject is often large, while both sample size and sampling intensity can vary substantially across individuals, which complicates the analysis. In some settings, simplified summaries of individual profiles, such as averages computed across the study period, are used for downstream analyses, including regression-style modeling. Although such summaries can be convenient, they may fail to fully capture dynamic temporal patterns present in the complete longitudinal profiles. To address this, we borrow measures from sequence analysis that capture individual-level patterns over time and then applied principal component analysis (PCA) followed by $K$-means clustering to identify unobserved latent groups of individuals with similar profiles. We test our approach using simulated data from a categorical functional regression model and compare its performance with two commonly used methods for detecting unobserved group structures: latent class analysis (LCA), and latent transition analysis (LTA). Using EMA stress observations from a large sample of U.S. adults (Newman et al., 2024, 2025), we identify distinct latent stress profile groups and show that they improve characterization of the impact on cognitive performance.

  PublisherDOI

• Contextualizing cognition: Socio-environmental factors shape how momentary stress predicts memory

  Social Science & Medicine · 2025-08-09

  article
  PublisherDOI

• Know Your Heart Better: Multimodal Cardiac Output Monitoring using Earbuds

  2025-03-12 · 3 citations

  article

  Cardiac Output (CO) is a critical indicator of health, offering insights into cardiac dysfunction, acute stress responses, and cognitive decline. Traditional CO monitoring methods, like impedance cardiography, are invasive and impractical for daily use, leading to a gap in continuous, non-invasive monitoring. Although recent advancements explored wearables on heart rate monitoring, these approaches face challenges in accurately estimating CO due to the indirect nature of the signals. To address these challenges, we introduce EarCO, a non-invasive multimodal CO monitoring system with Photoplethysmography and Ballistocardiogram signals on commodity earbuds. A novel feature fusion method is proposed to integrate raw signals and prior knowledge from both modalities, improving the system’s interpretability and accuracy. EarCO achieves an error of 1.080 L/min in the leave-one-subject-out settings with 62 subjects, making cardiovascular health monitoring accessible and practical for daily use.

  PublisherDOI

• The impact of acute stress on the HIV reservoir: a prospective interventional trial

  Journal of Virus Eradication · 2025-10-11

  articleOpen access

  T cells is the major barrier to cure of people with HIV (PWH) on antiretroviral therapy (ART). While most latently infected cells are transcriptionally silent, some express low levels of cell associated (CA) HIV RNA. In this prospective controlled interventional study, we tested the hypothesis that acute psychological stress could drive HIV transcription in PWH on ART. PWH on suppressive ART underwent the Trier Social Stress Test (TSST) and comparisons were made to a similar period of time without an intervention (control). During the test, physiological markers of acute psychological stress including pre-ejection period and cardiac output changed in all participants, as anticipated. Compared to the control day, the TSST led to a significant increase in CA HIV RNA with no change in the level of cell associated HIV DNA, indicating an increase in HIV transcription in response to stress. Change in HIV transcription was associated with physiological markers of stress but not with changes in immune cells. These data demonstrate that HIV transcription is increased following acute stress and have implications on the impact of stress on the HIV reservoir and the design of cure strategies for PWH.

  PublisherDOI

• Classifying Physiological Stress Responses: Distinguishing Threat Versus Challenge Using Earbuds

  2025-12-08

  article

  Stress is an inherent aspect of daily life and the use of consumer wearables for stress monitoring has grown significantly. However, existing stress monitoring technologies frequently detect physiological arousal triggered by routine demands, but face challenges in distinguishing between negative stress, such as threat, and positive stress, such as challenge. This differentiation is crucial in minimizing false alarms in stress management notifications and enabling personalized interventions specifically linked to negative stress arousal. To tackle this problem, we leverage advanced biomarkers by detecting ballistocardiogram (BCG) responses through earbud motion sensors and integrating them with biomarkers derived from earbud photoplethysmography (PPG) sensors. A meticulously designed study was conducted to elicit both threat and challenge responses in a controlled laboratory environment. Participants wore custom-designed earbuds for synchronized PPG and accelerometer (BCG) data collection, along with a reference biosig-nal acquisition system. We developed a biomarker extraction pipeline utilizing state-of-the-art BCG and PPG signal processing algorithms to filter low-quality signals and accurately extract advanced physiological biomarkers that capture information related to both challenge and threat responses. Our findings reveal that algorithms applied to earbud data can effectively extract stress biomarkers for arousal detection and differentiate between threat and challenge arousal, achieving an F1-score of up to 81%.

  PublisherDOI

• Socioeconomic Status Shapes Dyadic Interactions: Examining Behavioral and Physiologic Responses

  Psychological Science · 2025-07-14 · 1 citations

  articleSenior author

  With more opportunities for diverse interactions, little is known about how social interactions involving people of different socioeconomic status (SES) may unfold. We investigated social-attunement patterns in dyadic interactions involving SES. Unacquainted adults recruited from a community in the United States interacted with similar-or-different-SES partners in the lab ( N = 130 dyads). Attunement was assessed throughout the interaction by examining physiological linkage —how much a person’s physiological change is predicted by another’s physiological change over time. Overall, low-SES participants showed stronger physiological linkage—indicating greater attunement—to partners across SES. Participants also appeared more comfortable when interacting with low-SES partners. There were no SES differences in dominance during the conversation. After the interaction, participants reported liking similar-SES partners more than different-SES partners. These patterns suggest that during interactions, lower-SES individuals are more other-focused than high-SES individuals, and in-group preference prevails. We note limitations in the racial representation of our sample.

  PublisherDOI

Recent grants

• Affect contagion: Exploring the catalytic effects of status

  NSF · $490k · 2014–2017

• Advancing Psychosocial and Biobehavioral Stress Measurement and Interventions to Promote Healthy Aging

  NIH · $6.2M · 2014–2029

• Psychology and Medicine: An Integrative Research Approach

  NIH · $5.6M · 1991–2023

• Advancing Psychosocial & Biobehavioral Approaches to Improve Emotional Well-Being

  NIH · $2.7M · 2021–2026

• NIH Grant F31MH012013

  NIH · $59k

Frequent coauthors

• Patience A. Afulani

  University of California, San Francisco

  40 shared

• Brenda Major

  36 shared

• Jaffer Okiring

  Infectious Diseases Research Collaboration

  31 shared

• Raymond Aborigo

  Navrongo Health Research Centre

  29 shared

• Irene Kuwolamo

  Navrongo Health Research Centre

  27 shared

• Jason A. Okonofua

  26 shared

• Jim Blascovich

  University of California, Santa Barbara

  21 shared

• Sarah S. M. Townsend

  18 shared