Category: News and Events

The CSS seminar speakers for Friday, April 28 will be Stephen Davies and Hannah Zontine from the University of Mary Washington. Their talk entitled The “Hidden Trump Model”: Modeling social desirability bias through ABMs (abstract below) is scheduled to begin at 3:00 in the Center for Social Complexity Suite located on the 3rd floor of Research Hall. The talk will be followed by a Q&A session along with light refreshments.

This session will be live-streamed on the newly created CSS program YouTube channel: https://www.youtube.com/channel/UC7YCR-pBTZ_9865orDNVHNA

For announcements regarding this and future streams, please join the CSS/CDS student and alumni Facebook group.

For a list of upcoming and previous seminars, please visit here.

We hope to see you on Friday, April 28th.

ABSTRACT: Social desirability bias is a tendency people have to lie about their opinions if they perceive they will be judged or rejected. We present an Opinion Dynamics model in which agents may not be truthful about their opinions when they interact with their social circle. We model two processes through which agents influence one another: an online anonymous process in which agents can interact with anyone and do not fear social rejection, and a face-to-face process where they interact only with friends and may feel compelled to conform. In a political setting, this would apply to a race in which one of the candidates bears a social stigma and therefore some agents are reluctant to voice support for him or her. The results that these nonlinear and asymmetrical processes will have on the overall electorate are not obvious, and are well suited to an agent-based study.

We hypothesize that this model will produce a “poll bias” of the kind we saw in the 2016 Presidential election — i.e., a significant difference between the number of agents who say they will vote for a candidate and the number who actually do so on election day. We present an analysis of this “Hidden Trump model” and describe the way in which poll bias depends on the strength of the various interaction processes.

Recent Postings

• *The programs and services offered by George Mason University are open to all who seek them. George Mason does not discriminate on the basis of race, color, religion, ethnic national origin (including shared ancestry and/or ethnic characteristics), sex, disability, military status (including veteran status), sexual orientation, gender identity, gender expression, age, marital status, pregnancy status, genetic information, or any other characteristic protected by law. After an initial review of its policies and practices, the university affirms its commitment to meet all federal mandates as articulated in federal law, as well as recent executive orders and federal agency directives.

You are invited to attend the next scheduled Krasnow Monday Seminar on March 20. Dr. Bill Kennedy, Center for Social Complexity and CSS, will present “The Challenge of Modeling Cognition for Computational Social Science.”

Abstract

Computational Social Science (CSS) uses models of cognition, mostly human cognition. Zero intelligence agents may be useful for some economic experiments and agents with preferences about their neighbors and moving randomly may demonstrate the emergence of segregation, but better models of individual’s cognition are needed to advance CSS. This talk will review the development of some of the models of cognition that have been used in the Center for Social Complexity, are being developed in the Center, and are being planned for the future.

Krasnow seminars are held in room 229 of the Krasnow Building on Mason’s Fairfax campus Mondays from 4pm-5pm.

Recent Postings

• *The programs and services offered by George Mason University are open to all who seek them. George Mason does not discriminate on the basis of race, color, religion, ethnic national origin (including shared ancestry and/or ethnic characteristics), sex, disability, military status (including veteran status), sexual orientation, gender identity, gender expression, age, marital status, pregnancy status, genetic information, or any other characteristic protected by law. After an initial review of its policies and practices, the university affirms its commitment to meet all federal mandates as articulated in federal law, as well as recent executive orders and federal agency directives.

Due to the CDS department all-day training session on March 10 and spring break on March 17, there will be no CSS seminars on these dates. The seminar series will resume on Friday, March 24 with Antoine Mandel, Associate Professor, CES-Centre d’Economie de la Sorbonne. Professor Mandel’s talk entitled “Endogenous Growth in Production Networks” (abstract follows) is scheduled to begin at 3:00 in the Center for Social Complexity Suite located on the 3rd floor of Research Hall. The talk will be followed by a Q&A session along with light refreshments. Dr. Mandel’s paper is available upon request to Karen Underwood.

The session will be live-streamed on the newly created CSS program YouTube channel.

For announcements regarding this and future streams, please join the CSS/CDS student and alumni Facebook group.

Please visit the CDS calendar to see list of upcoming seminar speakers.

CSS Seminars are scheduled by the Department of Computational Data Sciences and co-hosted by CDS and the Center for Social Complexity.

Recent Postings

• *The programs and services offered by George Mason University are open to all who seek them. George Mason does not discriminate on the basis of race, color, religion, ethnic national origin (including shared ancestry and/or ethnic characteristics), sex, disability, military status (including veteran status), sexual orientation, gender identity, gender expression, age, marital status, pregnancy status, genetic information, or any other characteristic protected by law. After an initial review of its policies and practices, the university affirms its commitment to meet all federal mandates as articulated in federal law, as well as recent executive orders and federal agency directives.

The CSS seminar speaker for Friday, February 27 will be Yang Zhou, PhD Student, Computational Social Science, Department of Computational and Data Sciences, George Mason University. Yang’s talk, entitled “The Origin of Agriculture in the Peiligang Culture: An Agent-based Modeling Approach” (abstract below), is scheduled to begin at 3:00 in the Center for Social Complexity Suite located on the 3rd floor of Research Hall. The talk will be followed by a Q&A session along with light refreshments.
This session will be live-streamed on the newly created CSS program YouTube channel: https://www.youtube.com/channel/UC7YCR-pBTZ_9865orDNVHNA

Abstract: The emergence of agriculture played an important role in human history as it allowed people to move from a nomadic (i.e. hunter-gather) to a sedentary (i.e. agricultural) lifestyle. This shift in lifestyle not only provided abundant food, but also sufficient numbers of non-cultivating specialists, which are necessary conditions for the rise of a civilization. However, questions about how and why agriculture originated have remained controversial. This paper explores the origin hypotheses of agriculture, using the canonical theory of social complexity as a framework to study the transition from hunter-gatherer to agricultural societies in the region of the Peiligang in China based on existing literature, and develops an agent-based model to simulate the transition process. The model assumes that a combination of population growth and gaining knowledge on plants drove the transition from hunter-gatherer to agriculture. Results show that based on the basic hypotheses and assumptions, the model is able to generate the key phases that are identical with the existing literature on such a transaction.

For announcements regarding this and future streams, please join the CSS/CDS student and alumni Facebook group .

Visit our calendar to see list of upcoming seminar speakers.

Recent Postings

• *The programs and services offered by George Mason University are open to all who seek them. George Mason does not discriminate on the basis of race, color, religion, ethnic national origin (including shared ancestry and/or ethnic characteristics), sex, disability, military status (including veteran status), sexual orientation, gender identity, gender expression, age, marital status, pregnancy status, genetic information, or any other characteristic protected by law. After an initial review of its policies and practices, the university affirms its commitment to meet all federal mandates as articulated in federal law, as well as recent executive orders and federal agency directives.

Dr. Nigel Gilbert of the University of Surrey, a leading scientist in the field of Computational Social Science, as well as long-time friend of our Center and a member of our original External Board, has been appointed Commander of the British Empire (CBE) by H.M. Queen Elizabeth II. Congratulations, Nigel!

• *The programs and services offered by George Mason University are open to all who seek them. George Mason does not discriminate on the basis of race, color, religion, ethnic national origin (including shared ancestry and/or ethnic characteristics), sex, disability, military status (including veteran status), sexual orientation, gender identity, gender expression, age, marital status, pregnancy status, genetic information, or any other characteristic protected by law. After an initial review of its policies and practices, the university affirms its commitment to meet all federal mandates as articulated in federal law, as well as recent executive orders and federal agency directives.

Doctorates in Computational Social Science were conferred upon ten of our CSS students at the recent Convocation ceremony for the College of Science. We are so proud of them and of their tremendous accomplishment. Following are the students along with the titles of their dissertations:

• Thomas J. Dover, Implementing a Complex Social Simulation of the Violent Offending Process: The Promise of a Synthetic Offender
• Jose Manuel Magallanes, Climate Change and the Potential for Conflict and Extreme Migration in the Andes: A Computational Approach for Interdisciplinary Modeling and Anticipatory Policy Making
• David P. Masad, Agents in Conflict: Comparative Agent-based Modeling of Intrnational Crises and Conflicts
• Hugh James McFarlane, An Agent-based Model of Community Authority Structure Resilience
• Cristina Metgher, A Computational Social Science Approach to the Social Determinants of Cancer
• Nathan Palmer, Individual and Social Learning: Bounded Rationality from First Principles
• Ovi Chris Rouly, Towards Emergent Social Complexity
• Holly Ann Russo, Explaining Box Office Performance from the Bottom up: Data, Theories, and Models
• Stephen L. Scott, Computational Modeling for Marine Resource Management
• Hyungsik Shin, An Essay on Micro Heterogeneity and the Evolution of Inequality

Posted 5/12/16.

Recent Postings

• *The programs and services offered by George Mason University are open to all who seek them. George Mason does not discriminate on the basis of race, color, religion, ethnic national origin (including shared ancestry and/or ethnic characteristics), sex, disability, military status (including veteran status), sexual orientation, gender identity, gender expression, age, marital status, pregnancy status, genetic information, or any other characteristic protected by law. After an initial review of its policies and practices, the university affirms its commitment to meet all federal mandates as articulated in federal law, as well as recent executive orders and federal agency directives.

Multi-Level Regulation in Mammalian Circadian Clock

Casey Diekman (Department of Mathematical Sciences, New Jersey Institute of Technology)

DATE: Monday, 11 April, 2016
TIME: 4:00-5:00pm
LOCATION: Lecture Room (Room 229)
Krasnow Institute Building
George Mason University, Fairfax, VA

Abstract:

Circadian (~24-hour) rhythms offer one of the clearest examples of the interplay between different levels of nervous system organization, with dynamic changes in gene expression leading to daily rhythms in neural activity, physiology, and behavior. The main output signal of the master circadian clock in mammals has long been believed to be a simple day/night difference in the firing rate of neurons within the suprachiasmatic nucleus (SCN). Our recent findings challenge this theory, and demonstrate that a substantial portion of SCN neurons exhibit a more complex and counterintuitive set of electrical state transitions throughout the day/night cycle. In this seminar, I will attempt to provide a mathematical understanding of these daily transitions in SCN electrical state and the functional roles they play in the mammalian circadian clock.

Recent Postings

• *The programs and services offered by George Mason University are open to all who seek them. George Mason does not discriminate on the basis of race, color, religion, ethnic national origin (including shared ancestry and/or ethnic characteristics), sex, disability, military status (including veteran status), sexual orientation, gender identity, gender expression, age, marital status, pregnancy status, genetic information, or any other characteristic protected by law. After an initial review of its policies and practices, the university affirms its commitment to meet all federal mandates as articulated in federal law, as well as recent executive orders and federal agency directives.

Friday, March 18
3:00 p.m.
Research Hall, Suite 373-381

Tom Dover, PhD Candidate, Computational Social Science Program, Department of Computational and Data Sciences, George Mason University, will speak on: Toward Implementing a Complex Social Simulation of the Offending Process: The promise of a synthetic offender

For upcoming seminars from Computational Social Science, click here

Recent Postings

• *The programs and services offered by George Mason University are open to all who seek them. George Mason does not discriminate on the basis of race, color, religion, ethnic national origin (including shared ancestry and/or ethnic characteristics), sex, disability, military status (including veteran status), sexual orientation, gender identity, gender expression, age, marital status, pregnancy status, genetic information, or any other characteristic protected by law. After an initial review of its policies and practices, the university affirms its commitment to meet all federal mandates as articulated in federal law, as well as recent executive orders and federal agency directives.

Monday, March 14, 3pm
Krasnow Institute Room 229
Fairfax Campus

How Firing Rate Heterogeneity is Mediated by Intrinsic and Network Heterogeneity

Cheng Ly
Assistant Professor, Statistics & Operations Research Department
Virginia Commonwealth University

Abstract:
Heterogeneity of neural attributes has recently gained a lot of attention and is increasing recognized as a crucial feature in neural processing. Recent experimental recordings in electric fish indicate that the heterogeneous network input can mediate response heterogeneity of superficial pyramidal cells in a cortical area (Marsat Lab, WVU). These data motivated us to theoretically study how heterogeneity of neural attributes in general alter firing rate heterogeneity. We ask how 2 sources of heterogeneity: network (synaptic heterogeneity) and intrinsic heterogeneity alter response heterogeneity.

First we address this in a canonical recurrent spiking network model with random connectivity (Erdos-Renyi graph). The relationship between intrinsic and network heterogeneity can lead to amplification or attenuation of firing rate heterogeneity, and these effects depend on whether the recurrent network is firing asynchronously or rhythmically. We analyze the system and derive compact analytic formulas to precisely describe the phenomena.

Second, we adapt our theory to a delayed feedforward neural network to better model the electric fish system. The theory is used to demonstrate that a feedforward network with structured connectivity rules exhibit qualitatively similar statistics as the experimental data. Specifically, the stimulus tuning of particular cells is related to the network architecture, i.e., the number of synaptic connections. Thus, the model demonstrates that intrinsic and network attributes do not interact in a linear manner but rather in a complex stimulus-dependent fashion to increase or decrease response heterogeneity and thus shape population codes.

This is joint work with Gary Marsat (West Virginia University).

The Krasnow Institute hosts a seminar at 4:00 p.m. each Monday afternoon during the academic year with invited guest speakers presenting on a topic in the cognitive sciences. Click here for upcoming seminars.

• *The programs and services offered by George Mason University are open to all who seek them. George Mason does not discriminate on the basis of race, color, religion, ethnic national origin (including shared ancestry and/or ethnic characteristics), sex, disability, military status (including veteran status), sexual orientation, gender identity, gender expression, age, marital status, pregnancy status, genetic information, or any other characteristic protected by law. After an initial review of its policies and practices, the university affirms its commitment to meet all federal mandates as articulated in federal law, as well as recent executive orders and federal agency directives.

We extend congratulations to Jose Manuel Magallanes, Professor of Political Science at the Pontifical Catholic University of Peru in Lima, and former Research Associate at the Center for Social Complexity, who successfully defended his Computational Social Science Ph.D. dissertation on climate change in the Andes, glacial thawing, and human security. Dr. Magallanes is now a Senior Data Science Fellow at the University of Washington in Seattle.

Recent Postings

• *The programs and services offered by George Mason University are open to all who seek them. George Mason does not discriminate on the basis of race, color, religion, ethnic national origin (including shared ancestry and/or ethnic characteristics), sex, disability, military status (including veteran status), sexual orientation, gender identity, gender expression, age, marital status, pregnancy status, genetic information, or any other characteristic protected by law. After an initial review of its policies and practices, the university affirms its commitment to meet all federal mandates as articulated in federal law, as well as recent executive orders and federal agency directives.