Events
Past Event
WED@NICO WEBINAR: Tauhid Zaman, Yale School of Management "Detecting Bots and Assessing Their Impact in Social Networks"
Northwestern Institute on Complex Systems (NICO)
12:00 PM
Details
Speaker:
Tauhid Zaman, Associate Professor of Operations Management, Yale School of Management
Title:
Detecting Bots and Assessing Their Impact in Social Networks
Abstract:
Online social networks are often subject to influence campaigns by malicious actors through the use of automated accounts known as bots. We consider the problem of detecting bots in online social networks and assessing their impact on the opinions of individuals. We begin by developing a bot detection algorithm based on the Ising model from statistical physics. This algorithm can simultaneously identify multiple bots based on their network interaction patterns. Our Ising model algorithm can identify bots with higher accuracy while utilizing much less data than other state of the art methods.
We then develop a function we call generalized harmonic influence centrality to estimate the impact bots have on the opinions of users in social networks. This function is based on a generalized opinion dynamics model which subsumes many other models. We prove that this model reaches an equilibrium characterized by a set of linear equations. By combining a neural network for measuring sentiment with the observed social network structure, we are able to calculate the generalized harmonic influence centrality of bots in multiple real social networks involving the 2016 US presidential election, Brexit, and the Gilets Jaunes protests in France. For some networks we find that a limited number of bots can cause non-trivial shifts in the population opinions. In other networks, we find that the bots have little impact. Overall we find that generalized harmonic influence centrality is a useful operational tool to measure the impact of bots in social networks.
Speaker Bio:
Tauhid Zaman is an Associate Professor of Operations Management at the Yale School of Management. He received his BS, MEng, and PhD degrees in electrical engineering and computer science from MIT. His research focuses on solving operational problems involving social network data using probabilistic models, network algorithms, and modern statistical methods. Some of the topics he studies in the social networks space include combating online extremists and assessing the impact of bots. His broader interests cover data driven approaches to investing in startup companies, algorithmic sports betting, and biometric data. His work has been featured in the Wall Street Journal, Wired, Mashable, the LA Times, and Time Magazine.
Webinar:
Zoom link: https://northwestern.zoom.us/j/92654679478
Passcode: nico
About the Speaker Series:
Wednesdays@NICO is a vibrant weekly seminar series focusing broadly on the topics of complex systems and data science. It brings together attendees ranging from graduate students to senior faculty who span all of the schools across Northwestern, from applied math to sociology to biology and every discipline in-between. Please visit: https://bit.ly/WedatNICO for information on future speakers.
Time
Wednesday, April 28, 2021 at 12:00 PM - 1:00 PM
Contact
Calendar
Northwestern Institute on Complex Systems (NICO)
WED@NICO SEMINAR: Brandon Ogbunu, Yale School of Medicine "Soft rules for biological engineering: context and complexity in evolutionary genetics and beyond"
Northwestern Institute on Complex Systems (NICO)
12:00 PM
//
Lower Level, Chambers Hall
Details
Speaker:
Brandon Ogbunu, Associate Professor, Yale School of Medicine
Title:
Soft Rules for Biological Engineering: Context and Complexity in Evolutionary Genetics and Beyond
Abstract:
In this seminar, I will discuss contemporary approaches to engineering of complex biological systems through the lens of cutting-edge ideas in evolutionary theory and population genetics.
Speaker Bio:
C. Brandon Ogbunu is an Associate Professor (Tenure) in the Department of Ecology and Evolutionary Biology at Yale University. He is a computational biologist whose research investigates complex problems in epidemiology, evolutionary & population genetics, and evolution. His work utilizes a range of methods, from experimental evolution, to biochemistry, applied mathematics, and evolutionary computation.
Location:
In person: Chambers Hall, 600 Foster Street, Lower Level
Remote option: https://northwestern.zoom.us/j/97538907404
PW: NICO26
About the Speaker Series:
Wednesdays@NICO is a vibrant weekly seminar series focusing broadly on the topics of complex systems, data science and network science. It brings together attendees ranging from graduate students to senior faculty who span all of the schools across Northwestern, from applied math to sociology to biology and every discipline in-between. Please visit: https://bit.ly/WedatNICO for information on future speakers.
Time
Wednesday, February 4, 2026 at 12:00 PM - 1:00 PM
Location
Lower Level, Chambers Hall Map
Contact
Calendar
Northwestern Institute on Complex Systems (NICO)
WED@NICO SEMINAR: Chenhao Tan, University of Chicago "Science in the Age of AI"
Northwestern Institute on Complex Systems (NICO)
12:00 PM
//
Lower Level, Chambers Hall
Details
Speaker:
Chenhao Tan, Associate Professor, Department of Computer Science and Data Science, University of Chicago
Title:
Science in the Age of AI
Abstract:
As AI becomes increasingly capable of following instructions and conducting analyses, I believe that scientists will increasingly play the role of selector and evaluator. In this talk, I will share our recent advances in AI-enabled hypothesis generation and research evaluation. Rather than treating AI hallucinations as obstacles to eliminate, we leverage data and literature to steer AI creativity toward generating effective hypotheses. I will also introduce HypoBench, a dedicated benchmark for evaluating hypothesis generation, which reveals significant room for potential improvement of current AI models. Finally, I will present ongoing work that formalizes the evaluation of research outcomes beyond the paper itself and use AI to conduct robust evaluation of research evaluation, with a case study on mechanistic interpretability.
Speaker Bio:
Chenhao Tan is an Associate Professor of Computer Science and Data Science at the University of Chicago, and directs the Chicago Human+AI Lab. He earned his PhD in Computer Science from Cornell University and dual bachelor's degrees in computer science and economics from Tsinghua University. His research focuses on human-centered AI, communication & intelligence, AI & Scientific Discovery, and AI alignment. His work has been covered by major news media outlets, including the New York Times and the Washington Post. He also won a Sloan research fellowship, an NSF CAREER award, an NSF CRII award, a Google research scholar award, research awards from Amazon, IBM, JP Morgan, and Salesforce, a Facebook fellowship, and a Yahoo! Key Scientific Challenges award.
Location:
In person: Chambers Hall, 600 Foster Street, Lower Level
Remote option: https://northwestern.zoom.us/j/92797125283
PW: NICO26
About the Speaker Series:
Wednesdays@NICO is a vibrant weekly seminar series focusing broadly on the topics of complex systems, data science and network science. It brings together attendees ranging from graduate students to senior faculty who span all of the schools across Northwestern, from applied math to sociology to biology and every discipline in-between. Please visit: https://bit.ly/WedatNICO for information on future speakers.
Time
Wednesday, February 11, 2026 at 12:00 PM - 1:00 PM
Location
Lower Level, Chambers Hall Map
Contact
Calendar
Northwestern Institute on Complex Systems (NICO)
WED@NICO SEMINAR: Alex Imas, University of Chicago "Agentic Interactions"
Northwestern Institute on Complex Systems (NICO)
12:00 PM
//
Lower Level, Chambers Hall
Details
Speaker:
Alex Imas, Roger L. and Rachel M. Goetz Professor of Behavioral Science, Economics, and Applied AI, University of Chicago, Booth School of Business
Title:
Agentic Interactions
Abstract:
Do human differences persist and scale when decisions are delegated to AI agents? In this talk we will explore an experimental marketplace in which individuals author instructions for buyer-and seller-side agents that negotiate on their behalf. We compare these AI agentic interactions to standard human-to-human negotiations in the same setting. First, contrary to predictions of more homogenous outcomes, agentic interactions lead to, if anything, greater dispersion in outcomes compared to human-mediated interactions. Second, crossing agents across counterparties reveals systematic dispersion in outcomes that tracks the identity and characteristics of the human creators; who designs the agent matters as much as, and often more than, shared information or code. Canonical behavioral frictions reappear in agentic form: personality traits shape agent behavior and selection on principal characteristics yields sorting. Despite AI agents not having access to the human principal's characteristics, demographics such as gender and personality variables have substantial explanatory power for outcomes, in ways that are sometimes reversed from human-to-human interactions. Moreover, we uncover significant variation in "machine fluency"-the ability to instruct an AI agent to effectively align with one's objective function-that is predicted by principals' individual types, suggesting a new source of heterogeneity and inequality in economic outcomes. These results indicate that the agentic economy inherits, transforms, and may even amplify, human heterogeneity. Finally, we highlight a new type of information asymmetry in principal-agent relationships and the potential for specification hazard, and discuss broader implications for welfare, inequality, and market power in economies increasingly transacted through machines shaped by human intent.
Speaker Bio:
Alex Imas studies behavioral economics with a focus on how people understand and mentally represent the choices they are facing. His research explores topics related to how people learn and make choices in settings with risk and uncertainty. He also studies the economics of artificial intelligence and discrimination. Alex’s work utilizes a variety of methods, including controlled laboratory experiments, field experiments, analysis of observational data and theoretical modeling.
Alex is the recipient of the 2023 Alfred P. Sloan Research Fellowship, the Review of Financial Studies Rising Scholar Award, the New Investigator Award from the Behavioral Science and Policy Association, the Hillel Einhorn New Investigator Award from the Society of Judgment and Decision Making, the Distinguished CESifo Affiliate Award, and the NSF Graduate Research Fellowship. He is the co-author, with Richard Thaler, of The Winner’s Curse: Behavioral Economics Anomalies, Then and Now. He is an Associate Editor at the Journal of the European Economic Association and on the editorial board of Psychological Science.
Location:
In person: Chambers Hall, 600 Foster Street, Lower Level
Remote option: https://northwestern.zoom.us/j/91389366431
PW: NICO26
About the Speaker Series:
Wednesdays@NICO is a vibrant weekly seminar series focusing broadly on the topics of complex systems, data science and network science. It brings together attendees ranging from graduate students to senior faculty who span all of the schools across Northwestern, from applied math to sociology to biology and every discipline in-between. Please visit: https://bit.ly/WedatNICO for information on future speakers.
Time
Wednesday, February 18, 2026 at 12:00 PM - 1:00 PM
Location
Lower Level, Chambers Hall Map
Contact
Calendar
Northwestern Institute on Complex Systems (NICO)
WED@NICO SEMINAR: Todd Florin and Nelson Sanchez-Pinto, Lurie Children's Hospital of Chicago and Northwestern Feinberg School of Medicine
Northwestern Institute on Complex Systems (NICO)
12:00 PM
//
Lower Level, Chambers Hall
Details
Speakers:
Todd Florin, MD, MSCE, Associate Division Head for Academic Affairs & Research, Division of Emergency Medicine, Ann & Robert H. Lurie Children’s Hospital of Chicago; Professor of Pediatrics (Emergency Medicine), Northwestern University Feinberg School of Medicine
L. Nelson Sanchez-Pinto, MD, MBI, Attending Physician, Critical Care, Ann & Robert Lurie Children’s Hospital of Chicago; Associate Professor of Pediatrics (Critical Care) and Preventive Medicine (Health and Biomedical Informatics), Northwestern University Feinberg School of Medicine
Title:
Center for Pediatric Acute & Critical Care Research & Innovation (PACCRI)
Abstract:
TBA
Speaker Bios:
Dr. Todd Florin is a founding co-director of PACCRI. He is a pediatric emergency medicine physician-scientist with interests in pediatric respiratory infections and expertise in clinical and molecular epidemiology, predictive analytics, and large-scale, multicenter clinical trials in the acute care setting. He is committed to generating and implementing the best evidence to allow for precision care tailored to each patient.
Dr. Nelson Sanchez-Pinto is a founding co-director of PACCRI. He is a pediatric critical care medicine physician-scientist with interests in sepsis and expertise in data science and clinical informatics. His goal is to develop, test, and operationalize AI-enabled predictive and prognostic enrichment strategies that can help clinicians provide more personalized and targeted care to critically ill children.
Location:
In person: Chambers Hall, 600 Foster Street, Lower Level
Remote option: https://northwestern.zoom.us/j/92586384543
PW: NICO26
About the Speaker Series:
Wednesdays@NICO is a vibrant weekly seminar series focusing broadly on the topics of complex systems, data science and network science. It brings together attendees ranging from graduate students to senior faculty who span all of the schools across Northwestern, from applied math to sociology to biology and every discipline in-between. Please visit: https://bit.ly/WedatNICO for information on future speakers.
Time
Wednesday, February 25, 2026 at 12:00 PM - 1:00 PM
Location
Lower Level, Chambers Hall Map
Contact
Calendar
Northwestern Institute on Complex Systems (NICO)
WED@NICO SEMINAR: Ágnes Horvát, Associate Professor, Northwestern School of Communication
Northwestern Institute on Complex Systems (NICO)
12:00 PM
//
Lower Level, Chambers Hall
Details
Speaker:
Ágnes Horvát, Associate Professor, Department of Communication Studies, Northwestern School of Communication
Title:
TBA
Abstract:
TBA
Speaker Bio:
Ágnes Horvát is an Associate Professor in the Department of Communication Studies, (by courtesy) the Computer Science Department of the McCormick School of Engineering, and (also by courtesy) the Department of Management and Organizations of the Kellogg School of Management.
Her research seeks to measure, understand, and forecast the collective behaviour of networked crowds in large-scale socio-technical systems. On the one hand, her current projects investigate the impact of network embeddedness and diversity on scholarly communication. On the other hand, she works on identifying expressions of collective intelligence and opportunities for innovation in crowdsourcing communities. Her research group also develops empirical and theoretical methods to support creativity and predict success in culture industries. This work lies at the intersection of computational social science and social computing. It uses an interdisciplinary data-driven approach that builds on techniques from network science, machine learning, and statistics.
Location:
In person: Chambers Hall, 600 Foster Street, Lower Level
Remote option: https://northwestern.zoom.us/j/96701776160
PW: NICO26
About the Speaker Series:
Wednesdays@NICO is a vibrant weekly seminar series focusing broadly on the topics of complex systems, data science and network science. It brings together attendees ranging from graduate students to senior faculty who span all of the schools across Northwestern, from applied math to sociology to biology and every discipline in-between. Please visit: https://bit.ly/WedatNICO for information on future speakers.
Time
Wednesday, March 4, 2026 at 12:00 PM - 1:00 PM
Location
Lower Level, Chambers Hall Map
Contact
Calendar
Northwestern Institute on Complex Systems (NICO)