About

Iris Donga Vilares is an Assistant Professor of Psychology at the University of Minnesota's College of Liberal Arts. Her research investigates how humans make decisions and how these processes differ in individuals with psychiatric and neurological diseases. She combines tools from cognitive neuroscience, neuroeconomics, and computational models to analyze decision-making, with a particular focus on decision-making under uncertainty. Her work explores both individual and social levels, examining how people integrate uncertain information in sensorimotor tasks and how they trust others amidst social uncertainty. Additionally, she studies how these decision-making processes are represented in the brain, using computational models to explain behaviors and provide a principled understanding of decision-making in health and disease. Her educational background includes a PhD in Neuroscience from Northwestern University and Universidade Nova de Lisboa, an MSc in Mathematics Applied to Biological Sciences from the Technical University of Lisbon, and a BSc in Biology from the University of Lisbon.

Research topics

• Psychiatry
• Psychology
• Clinical psychology
• Social psychology
• Medicine

Selected publications

• Investigating Sensorimotor Decision-Making in Depressed Individuals using a Bayesian Approach

  2026-04-23

  articleOpen accessSenior author

  Depression is one of the most common mental disabilities worldwide. People with depression may experience impaired cognitive functions, unusual reward and punishment processing, and other executive dysfunctions that affect daily life. Depression has also been associated with alterations in sensory perception, sensitivity, and processing speed. However, the relationship between depression and sensorimotor decision-making under uncertainty remains understudied. Our study aims to understand how individuals with depression process and weigh prior and current sensory information during sensorimotor decision-making. Here, we employed a visuomotor coin-catching task and the Bayesian Decision Theory framework to examine the relative reliance on current information in depressed and non-depressed individuals; specifically, we investigate if and how the reliance changed depending on the uncertainty of prior and current information. Behavioral analyses and computational models revealed that both groups combined prior knowledge and sensory input in a qualitatively Bayesian manner, giving more weight to current information when it was less uncertain and/or when the prior information was more uncertain. In addition, the groups did not significantly differ in their overall relative reliance on current information. Despite these overall similarities, several group differences emerged. Depressed participants responded faster when prior uncertainty was high, whereas non-depressed participants did not show this pattern. Moreover, while both groups adjusted their sensory weights as prior uncertainty changed, non-depressed participants exhibited more than twice the shift in sensory weighting compared to depressed individuals. Model-based analyses further showed that although Bayesian models fit both groups better than heuristic alternatives, model fit was worse in the depressed group, as indicated by higher mean squared errors (MSEs). In summary, these findings suggest that depression does not abolish Bayesian-like integration, but may attenuate sensitivity to changes in prior reliability and lead to faster, but potentially less adaptive, responses under prior uncertainty. Future work should examine how individual variability in clinical symptoms, task demands, and cognitive flexibility may moderate these effects.

  PublisherDOI

• Creative foraging and the explore–exploit trade-off in knowledge networks

  Cognition · 2026-02-11

  article
  PublisherDOI

• The influence of visibility and prevalence rate on visual search

  Journal of Vision · 2026-02-10

  articleOpen accessSenior author

  The low prevalence effect, which posits that people are more likely to miss a present target when its prevalence rate is low, has important implications for real-world scenarios such as cancer screening and bomb detection. This effect has primarily been studied under full visibility; however, real-world scenarios often come with incomplete visibility. Occlusion and poor visibility introduce perceptual uncertainty, potentially altering how people decide whether a target is present. Here, we applied Bayesian decision theory to a visual search paradigm with partial occlusion, examining how target prevalence (prior) and the degree of occlusion (likelihood information) affect search decisions. Participants made target present/absent responses to target/distractor stimuli. In Experiment 1, all items were invisible, forcing participants to rely on trial feedback to learn the target's prevalence. Experiment 2 also provided trial feedback, but allowed either a small or large portion of the display to be visible. Target prevalence varied between blocks (high, 50%; low, 25%). Results showed that, when items were entirely hidden, participants learned to probability match the target's prevalence. However, when some items were visible, participants rarely responded present when the target was in the occluded region. Comparing the data with models (e.g., probability matching, Bayesian maximizing) revealed mixed strategies. This study introduces a novel method for investigating visual search under occlusion and suggests that, although people integrate prevalence and sensory input, their decisions are not fully Bayesian.

  PublisherOA PDFDOI

• Learning from the Crowd: the Statistical Information of Others Shapes the Magnitude and Variability of Individual Donation Behavior

  2026-04-18

  articleOpen accessSenior author

  Charitable giving is a cornerstone of social welfare, and others’ donations can promote individual giving. However, the mechanisms through which social information shapes donation behavior, and how individuals differ in their responsiveness, remain poorly understood. Here, we investigated how the statistical properties of others’ donations, specifically their mean and variability, shape individual giving, and how this was affected by individual differences. Across 4 pre-registered experiments (total N = 1,491), participants made donations before and after observing sequential donations from diverse others whose mean and variability were systematically manipulated. We found that observing generous average donations robustly increased individual giving, while observing stingy donations decreased it. Moreover, the variance in social information did not modulate this shift. In parallel, exposure to others’ donations consistently reduced the variability of individual donations, with stronger reductions when others’ donations were more consistent (versus more variable). These effects also generalized to novel donation contexts. At the individual level, changes in donations following social exposure were consistently positively associated with psychopathic traits. Computational modeling further revealed that people with higher psychopathic traits were more susceptible to social information, assigning greater weight to observed donations when making their second decisions. These results were replicated across all experiments, despite variations in donation magnitudes, population type, variability discrepancy, and incentive structures. Together, our findings demonstrate that the statistical structure of social information - its magnitude and variability - shapes the corresponding features of individual donations, and identify psychopathy as a key factor underlying heterogeneity in social influence.

  PublisherDOI

• Information seeking and the expected utility of information about COVID-19 can be associated with uncertainty and related attitudes

  Scientific Reports · 2025-02-19 · 2 citations

  articleOpen accessSenior author

  Understanding how people decide when to seek out information can offer important insights into best practices for scientific communication, which may be critical in the face of global challenges like the COVID-19 pandemic. We examined how expected information utility, affective characteristics, and attitudes predicted COVID-19 information seeking behavior in a sample of 191 midwestern undergraduate students in late 2020. Participants completed five rounds of an information seeking task in which they read about a potential gap in their knowledge about COVID-19 and chose whether to read an excerpt that could fill that information gap. We found that information seeking in a given round (i.e. "round-wise information seeking") was best predicted by expected cognitive utility (i.e., expected reduced uncertainty). When collapsed across rounds, information seeking was positively correlated with COVID-19 preventive behaviors and trust in science, which also correlated with each other. Additionally, exploratory analyses regressing round-wise utility ratings on personality variables revealed that intolerance of uncertainty was associated with higher ratings of all three information utilities. Together, these results suggest that pandemic-related information seeking may have been especially driven by how individuals relate to and manage uncertainty. We discuss how these findings relate to extant literature on information utility and seeking behaviors and highlight the potential for work in this area to improve scientific communication.

  PublisherOA PDFDOI

• Victims of conspiracies? An examination of the relationship between conspiracy beliefs and dispositional individual victimhood

  2025-02-03

  preprintOpen access

  Conspiracy beliefs have been linked to perceptions of collective victimhood. We adopt an individual perspective on victimhood by investigating the relationship between conspiracy beliefs and the individual disposition to perceive and react to injustice as a victim (i.e., victim justice sensitivity; VJS). Data from two German samples (Ns = 370, 373) indicated a positive association between VJS and conspiracy mentality beyond conceptually related covariates (e.g., mistrust). In a multinational sample from 15 countries (N = 14,978), VJS was positively associated with both general and specific conspiracy beliefs (about vaccines and climate change) within countries, though these associations varied across countries. However, economic, sociopolitical, and cultural country-level factors that might explain the cross-country variability (e.g., GDP, Human Freedom Index, Individualism-Collectivism), including indices of collective exposure to direct violence, did not moderate the studied associations. Future research should investigate the association between victimhood and conspiracy beliefs considering both intraindividual and intergroup perspectives.

  PublisherDOI

• WITHDRAWN

  2025-06-24

  preprintOpen access

  sampling procedure, research materials, hypothesis, and analysis plan (

  PublisherOA PDFDOI

• Victims of Conspiracies? An Examination of the Relationship Between Conspiracy Beliefs and Dispositional Individual Victimhood

  European Journal of Social Psychology · 2025-07-17 · 5 citations

  articleOpen access

  ABSTRACT Conspiracy beliefs have been linked to perceptions of collective victimhood. We adopt an individual perspective on victimhood by investigating the relationship between conspiracy beliefs and the individual disposition to perceive and react to injustice as a victim, i.e., victim justice sensitivity (VJS). Data from two German samples (Ns = 370, 373) indicated a positive association between VJS and conspiracy mentality beyond conceptually related covariates (e.g., mistrust). In a multinational sample from 15 countries ( N = 14,978), VJS was positively associated with both general and specific conspiracy beliefs (about vaccines and climate change) within countries, though these associations varied across countries. However, economic, sociopolitical and cultural country‐level factors that might explain the cross‐country variability (e.g., GDP, Human Freedom Index, individualism–collectivism), including indices of collective exposure to direct violence, did not moderate the studied associations. Future research should investigate the relationship between victimhood and conspiracy beliefs, considering both intraindividual and intergroup perspectives.

  PublisherOA PDFDOI

• Cultural tightness predicts higher levels of generic and content-specific conspiracy beliefs: Cross-country, correlational and experimental evidence

  2025-06-03

  preprintOpen access

  Conspiracy theories polarize people in different cultural contexts around important issues such as climate change and the COVID-19 pandemic. Across four studies, we examined whether cultural tightness, that describes the extent to which social norms are strictly enforced and deviance is discouraged, predicts various conspiracy beliefs, demonstrating a robust relationship between these two variables. In Study 1 (N = 31,894), we found that cultural tightness positively predicted COVID-19 conspiracy beliefs, after controlling for individual- and country-level variables. Study 2 (N = 9,000) extended these findings to climate change, vaccine-related, and generic conspiracy beliefs. Study 3 (N = 370) examined this relationship at the individual level, showing that perceived cultural tightness predicted climate change and generic conspiracy beliefs, and that this relationship was mediated by the need for cognitive closure. Study 4 (N = 390) experimentally manipulated perceived tightness indicating that individuals exposed to a scenario about a future society based on law and order (tightness condition) reported higher climate change and generic conspiracy beliefs compared to those in the loose (a future society based on openness) and control (no scenario) conditions. These findings are discussed in light of cultural factors that can breed conspiracy beliefs.

  PublisherDOI

• The Effects of Arbitrary Social Comparison on Trust and Risky Decision-Making

  2025-09-22

  articleOpen accessSenior author

  Numerous fields have demonstrated that our decisions are guided by social information, and one important piece of social information is social comparison. Previous research has suggested that social status can influence trust, but most prior studies examining the influence of social comparison on trust decisions employed social comparison contexts that potentially “justify” the difference in social status, such as performing better/worse in a task. The current study investigated how, instead, interpersonal trust and risk-related decisions are made after experiencing arbitrarily manipulated social comparison contexts. In addition, the study directly compared people’s behaviors in trust and risk environments under different social positions in a single experimental paradigm. Across two experiments (Experiment 1: discovery sample, N = 302; Experiment 2: validation sample, N = 299), we showed that exposure to randomly manipulated social comparison contexts significantly influenced participants’ economic allocation decisions, their perceived relative ranks, and their reported levels of envy towards their target of comparison. However, our findings suggest that participants’ subsequent decision-making regarding interpersonal trust and risk-taking were not affected by this arbitrary-based social comparison. Our results also show that participants perceived risk and trust environments differently, with smaller amounts invested in the risk scenario than in the trust scenario. Overall, our findings indicate which behaviors and feelings are more likely to be affected by being randomly placed in a favorable or unfavorable social comparison scenario, and increase our understanding of trust and risk across social comparison scenarios.

  PublisherDOI

Frequent coauthors

• Konrad P. Körding

  44 shared

• Zuzanna Tajchman

  University of Minnesota

  34 shared

• P. Read Montague

  29 shared

• Hugo L. Fernandes

  29 shared

• Nathan Torunsky

  University of Minnesota

  26 shared

• Sébastien Massoni

  24 shared

• Jana B. Berkessel

  24 shared

• Mathi Manavalan

  University of Minnesota

  24 shared