About

David M. Williams is a Professor of Behavioral and Social Sciences, as well as a Professor of Psychiatry and Human Behavior at Brown University. He also serves as the Associate Dean of the School of Public Health. Dr. Williams holds a BS in psychology from Stockton University and a PhD in clinical psychology from Virginia Tech. Since joining Brown University’s research faculty in 2006 and the teaching faculty in 2009, his work has focused on health behavior science, particularly examining the psychological and social determinants of health-related behaviors such as exercise, smoking cessation, and weight management. His research explores affective responses to physical activity, self-regulation, outcome expectancy, and motivation, contributing to the development of theory-based interventions aimed at promoting healthy behaviors. Dr. Williams has authored two books on health behavior and has an extensive publication record, including articles that investigate the mediators and moderators of health behavior change, the role of affect and self-efficacy, and the efficacy of various intervention strategies.

Research topics

• Computer Science
• Radiology
• Developmental psychology
• Social psychology
• Intensive care medicine
• Cognitive psychology
• Medicine
• Linguistics
• Psychology
• Communication

Selected publications

• Links between gender diversity and autism traits in non-autistic cisgender and transgender adults: Contributions of negative affect and alexithymia

  International Journal of Transgender Health · 2026-04-23

  articleOpen accessCorresponding

  Background: Much of the literature on Autism–gender diversity (GD) relies on self-report Autism screening questionnaires (e.g. Autism-spectrum Quotient; AQ-50) that may tap constructs other than Autism. Aims: In two studies, we tested whether links between GD traits or categorical gender modality (cisgender/transgender) and Autism traits in non-Autistic cisgender and transgender adults reflect variance shared with alexithymia/negative affect. Methods: Study 1 (N = 285 cisgender adults) measured Autism traits (AQ-50), alexithymia, negative affect, perceived discrimination, and dimensional GD. Study 2 (N = 208; 104 transgender and 104 cisgender) measured primarily Autism traits, alexithymia, and negative affect. Hierarchical regressions tested whether dimensional GD (Study 1) and being transgender(Study 2) predicted AQ-50 scores before and after other measures were included. Additionally, (a) mediations examined the interplay between alexithymia, negative affect, and Autism traits; (b) regressions tested whether dimensional GD or being transgenderpredicted “Autism-specific” AQ-50 variance, and; (c) groups in Study 2 were matched on alexithymia and negative affect, with differences in AQ-50 tested using independent t-tests. Results: Both dimensional GD indices (Study 1) and being transgender (Study 2) predicted higher Autism traits, but adding alexithymia and negative affect eliminated the predictive effects. Mediation analyses showed partial, bidirectional alexithymia-negative affect associations with Autism traits. Importantly, Autism-specific variance on the AQ-50 was not predicted by dimensional GD in Study 1 or transgender identity in Study 2. Moreover, the predictive effect of being transgender in Study 2 disappeared after matching groups on alexithymia and negative affect. Discussion: In non-Autistic cisgender and transgender people, associations between dimensional GD or being transgender and self-reported Autism traits became nonsignificant after accounting for alexithymia and negative affect. These findings caution against inferring Autism-specific links from screener totals. Clinically, elevated Autism traits alone in non-Autistic transgender people should not guide decisions.

  PublisherDOI

• Variation in compressive mechanical properties between subacute and chronic venous thrombosis in a novel unilateral iliac thrombosis model

  Vascular Medicine · 2025-01-21 · 1 citations

  article

  Background: Interventional therapies to relieve chronic deep vein thrombosis (DVT) fail through inability to penetrate, cross, and remove the occlusion. Development of suitable tools requires fundamental understanding of chronic DVT mechanical properties and a reliable model for testing. Methods: Female farm swine underwent a novel, endovenous generation of long-segment unilateral iliac vein thrombosis. Thrombus was confirmed via venogram, intravascular ultrasound, and transabdominal duplex for 14 days. Thrombus components were quantified via histology. Thrombus mechanical properties were assessed via uniaxial compression. Results: Among seven swine, technical success was 100%. Compared to subacute thrombi (7-day), chronic thrombi (14-day) showed organizing thrombus with diffuse myointimal thickening and collagen matrix formation on histology. The thrombi collagen content was 41% versus 55% ( p = 0.17) and the thrombus erythrocyte percentage was 4.3% versus 2.2%, p = 0.21 in 7- versus 14-day thrombi, respectively. The onset point (compression required to load the thrombus fiber network) was 66.6% versus 35.3% ( p = 0.004), the secant modulus (resistance to deformation) measured at the onset point was 153.8 versus 275.99 kPa ( p = 0.18), and the average shear constant (resistance to shearing), as defined by the Yeoh hyperelastic model, was 1.85 kPa versus 2.85 kPa in 7- versus 14-day thrombi. Conclusions: This study demonstrates the feasibility of an endovenous model generating chronic unilateral venous thrombi in 2 weeks with similar anatomy to humans and provides critical mechanical properties of thrombi for future research.

  PublisherDOI

• Assessing glycaemic impact of FreeStyle libre monitoring in patients with insulin-treated type 2 diabetes: a retrospective real-world analysis

  Journal of Diabetes & Metabolic Disorders · 2025-03-01 · 2 citations

  articleOpen access
  PublisherOA PDFDOI

• The Survival of Taxonomy and the Digitization of Natural History Collections*

  2025-05-12

  book-chapterSenior author

  The massive digitization projects of Natural History collections of either living or extinct organisms, specifically those conserved in herbaria, are today considered an unambiguously positive phenomenon (e.g., Blagoderov et al., 2012, p. 143; Sweeney et al., 2018). The availability of many collections in the form of high-quality digital images will allow a significant increase in the efficiency of the work of a botanist. For example, in many cases, there will now be no need to request specific collections or to make long trips to work with herbarium specimens. Digitization of herbarium specimens, which will eventually combine images obtained from various herbaria into giant databases, will make it possible to include multiple collections in various analyses that are not directly related to taxonomic goals and thus will expand the functionality of collection repositories. Geo-referencing of the digitized samples will make it possible to utilize specimen collections in ecological, morphological and climatic bio-informatic studies. Digitized samples can now be the target of various artificial intelligence (AI)-based studies. Translating collections into a digital format will protect the actual specimens from accidental destruction, such as fire or other disasters, and simultaneously preserve our rapidly extinct biodiversity. The list of possible benefits of digitization goes on. Popular explanations of ‘Why digitization matters’ can be found today on the Internet, in the pages of scientific and popular journals, Museum exhibitions, etc.

  PublisherDOI

• Versatile mixed methods for weakly-compressible flows

  Computers & Fluids · 2025-09-22

  articleSenior authorCorresponding
  PublisherDOI

• JWST Lensed Quasar Dark Matter Survey III: Dark Matter Sensitive Flux Ratios and Warm Dark Matter Constraint from the Full Sample

  ArXiv.org · 2025-11-11

  preprintOpen accessSenior author

  We present the full sample of measurements of the warm dust emission of 31 strongly-lensed, multiply imaged quasars, observed with JWST MIRI multiband imaging, which we use to constrain the particle properties of dark matter. The strongly lensed warm dust region of quasars is compact and statistically sensitive to a population of dark matter halos down to masses of $10^6$ M$_\odot$. The high spatial resolution and infrared sensitivity of MIRI make it uniquely suited to measure multiply imaged warm dust emission from quasars and thus to infer the properties of low-mass dark halos. We use the measured flux ratios to test for a warm dark matter turnover in the halo mass function. To infer the dark matter parameters, we use a forward modeling pipeline which explores dark matter parameters while also accounting for tidal stripping effects on subhalos, globular clusters, and complex deflector macromodels with $m=1, m=3, \text{ and } m=4$ elliptical multipole moments. Adopting a comparable prior on the projected density of substructure to our previous analyses, the data presented here provide a factor of 2 improvement in sensitivity to a turnover in the halo mass function. Assuming subhalo abundance predicted by the semi-analytic model galacticus we infer with a Bayes factor of 10:1, a half-mode mass $m_{\rm{hm}} < 10^{7.8} M_{\odot}$ (m>5.6 keV for a thermally produced dark matter particle). If instead we use a prior from N-body simulations, we infer $m_{\rm{hm}} < 10^{7.6} M_{\odot}$ (m>6.4 keV). This is one of the strongest constraints to date on a turnover on the halo mass function, and the flux ratios and inference methodology presented here can be used to test a broad range of dark matter physics.

  PublisherOA PDFDOI

• White‐tailed deer behaviors at three forage settings: Implications for transmission of chronic wasting disease

  Journal of Wildlife Management · 2025-05-12

  articleOpen access

  Abstract Chronic wasting disease (CWD) is induced by a protein found in cervid brains called prions that cause folding of other neural proteins. These prions are transmitted among individual cervids via direct (individual to individual), indirect (e.g., individual to environment), and self (e.g., licking an infected area) contacts. Supplemental feeding tends to concentrate deer ( Odocoileus spp.), with implications for inter‐individual prion transmission. Prion transmission depends on deer behaviors, yet information on behaviors at various forage settings is lacking. We quantified behaviors thought to play a role in prion transmission exhibited by white‐tailed deer ( O. virginianus ) at baited sites, food plots, and areas used for foraging in the surrounding landscape (hereafter landscape forage areas [LFAs]) using camera trapping and road‐based transect surveys during the post‐breeding period (January through April 2021–2023). We conducted 4,172 deer observations across all forage settings (15% from LFA transects, 69% from bait sites, 16% from food plots), and found fewer direct contacts (i.e., deer to deer) at food plots and LFAs compared to bait sites. We found a lower number of self‐contacts (e.g., deer licking a body part) at food plots compared to bait sites and observed fewer environmental contacts (e.g., deer potentially ingesting soil) at food plots and LFAs compared to bait sites. At bait sites, we found that yearling males had a greater tendency to directly contact male and female adults, with this tendency greatest when >2 adults were visible. We also measured deer fecal deposition at forage settings, as prions in feces are potentially available for uptake by uninfected individuals. The probability of finding a deer fecal pellet at food plots and LFAs was lower than at bait sites, but amount of fecal material did not vary among forage settings. Ordinal day negatively affected the probability of finding a deer pellet across all forage settings. Our findings indicate that the probability of direct and environmental contacts at bait sites exceeds contacts at food plots and LFAs. Additionally, higher probability of fecal deposition coupled with more environmental contacts at bait sites increases potential transmission of prions. In areas of concern for CWD, food plots and LFAs appear to offer less risky food sources for deer during the post‐breeding period compared to bait sites.

  PublisherOA PDFDOI

• Exercise That Feels as Good as Possible: Acceptability of an Affect‐Based Exercise Prescription Among Stage 0–III Breast Cancer Survivors

  Psycho-Oncology · 2025-07-30 · 1 citations

  articleOpen access

  BACKGROUND: Leaders in the field have called for exercise counseling to become standard of care by 2029. An Affect-based exercise prescription (Affect-Rx) may be a viable strategy for supporting this effort. AIMS: Guided by the ORBIT Model for developing behavioral treatments, this Phase 1b study evaluated breast cancer survivors' perceived acceptability of Affect-Rx. Additionally, the feasibility of trial methods and opportunities for protocol refinements were assessed. METHOD: Participants were 36 stage 0-III breast cancer survivors within 5 years of completing primary cancer treatment. Demographics were collected at baseline and via medical record review. Affect-Rx was delivered in conjunction with a low-touch, physical activity promotion intervention over videoconference call. At end-of-study, participants rated Affect-Rx using the Treatment Acceptability and Preferences (TAP) Measure. Participants responded to the Stanford L-Cat at baseline and end-of-study. ActiGraph wGT3X-BT accelerometers measured moderate-vigorous physical activity (MVPA) over 10-day periods at baseline and follow-up. RESULTS: Affect-Rx was rated acceptable (TAP overall M = 3.30, SD = 0.53). Study retention and accelerometer measurement completion was ≥ 80% across time. L-Cat scores were discordant from accelerometer-measured MVPA at baseline. CONCLUSIONS: Affect-Rx warrants further testing. The trial methods were feasible; however, physical inactivity verification procedures along with targeted recruitment efforts are needed to support future work. The field needs intervention strategies that can be deployed with limited resources and at low cost to offer survivors exercise counseling support in line with the new National Standards for Cancer Survivorship Care, the affect-based exercise prescription is designed to serve this mission. TRIAL REGISTRATION: The study protocol was registered with ClinicalTrials.gov prior to the initiation of participant recruitment NCT04903249.

  PublisherOA PDFDOI

• Aortic dissection associated with transcatheter aortic valve replacement: Implications of preexisting aortic pathologies

  JTCVS structural and endovascular. · 2025-04-09

  articleOpen access

  Objectives: Acute aortic dissection is a rare yet life-threatening complication associated with transcatheter aortic valve replacement (TAVR). Given its low incidence, the characteristics and risk factors remain inadequately investigated. Methods: Between 2011 and 2023, a total of 2558 TAVR procedures were performed at the University of Michigan. Among these, 12 patients (0.47%) developed aortic dissection. Additionally, 3 post-TAVR patients from other institutions presented with aortic dissection and were treated at our institution, yielding a total of 12 type A and 3 type B aortic dissections. Results: The median age was 79.5 years, and 5 (33.3%) exhibited end-organ malperfusion affecting the brain (n = 3), legs (n = 3), and kidneys (n = 1). TAVR device migration requiring repositioning was observed in 40% (6 out of 15) of cases. In type A dissections, the entry tear consistently occurred along the greater curvature. Patients with type A dissections had a larger pre-TAVR aortic diameter than those without dissection (41.6 mm vs 34.5 mm; P < .001). Preexisting aortic dilation (≥45 mm) was associated with a significantly increased risk of type A dissection (odds ratio, 12.0; 95% confidence interval 3.0-50.6; P < .001). Type A dissection was managed with open repair in 7 patients (58.3%), all of whom survived 30 days, and with endovascular aortic repair in 4 patients (33.3%), all of whom experienced mortality; 1 patient received palliative care. All type B dissections were successfully treated with endovascular repair. Conclusions: TAVR-related aortic dissection is characterized by preexisting aortic risk factors with various mechanisms. Current surgical guidelines recommending aortic repair for dilatation ≥45 mm should be strongly considered in patients undergoing TAVR evaluation.

  PublisherDOI

• TDCOSMO: XX. WFI2033--4723, the First Quadruply-Imaged Quasar Modeled with JWST Imaging

  arXiv (Cornell University) · 2025-02-28

  preprintOpen access1st authorCorresponding

  Gravitational time delays offer unique, independent measurements of the Hubble constant, $H_0$. Precise measurements of $H_0$ stand as one of the most pressing challenges in modern cosmology, and to do so with time delays requires precise lens models. While much work has focused on streamlining the modeling process to keep pace with the erumpent discovery of strongly-lensed systems, a critical step toward reducing uncertainty in $H_0$ comes from increasing the precision of individual lens models themselves. In this work, we demonstrate that the unprecedented imaging capabilities of JWST make this goal attainable. We present the first lens model for time-delay cosmography derived from JWST data, applied to the quadruply-imaged quasar WFI2033--4723. While the primary source of systematic uncertainty in time-delay cosmography is currently the mass-sheet degeneracy (MSD), the sensitivity of models to this MSD varies on how the point spread function (PSF) errors are mitigated. As the PSF is also the primary source of uncertainty in lens modeling, we focus on a comparison of different PSF modeling methods. Within the context of power-law models, we recover results in agreement with previous Hubble Space Telescope (HST)-based models, but with better precision of key lensing parameters through implementation of new PSF modeling techniques. Despite the record-holding precision of this system's HST modeling, we achieve an additional 22% increase in precision of the Fermat potential difference, directly reducing uncertainties of cosmological inference. These results would produce a 3% ($1σ$ of the modeling error) shift of $H_0$ towards a higher value for this lens, keeping all else constant. This work substantiates the groundbreaking potential of JWST for time-delay cosmography and lays the groundwork for modeling systems previously too faint to provide meaningful constraints on $H_0$.

  PublisherDOI

Recent grants

• NIH Grant R21CA137211

  NIH · $410k · 2012

• NIH Grant F32HL078709

  NIH · $62k · 2006

• Physical Activity Promotion Based on Positive Psychology: Development and Piloting of a Novel Intervention Approach

  NIH · $378k · 2018–2021

• NIH Grant P01AI022380

  NIH · $4.3M · 1993

• NIH Grant R01MH057425

  NIH · $458k · 2001

Frequent coauthors

• Michael P. Pender

  189 shared

• Anne‐Louise Ponsonby

  Murdoch Children's Research Institute

  182 shared

• Bruce Taylor

  University of Tasmania

  165 shared

• Ingrid van der Mei

  University of Tasmania

  153 shared

• Alan Coulthard

  University of Queensland

  152 shared

• Robyn Lucas

  Australian National University

  148 shared

• Shira Dunsiger

  John Brown University

  144 shared

• Patricia C. Valery

  143 shared

Education

• B.S., Psychology

  Stockton University

• Ph.D., Clinical Psychology

  Virginia Tech