Aaron Bramson

GA technolgies · AI Strategy Center

The geospatial characteristics of transportation networks structurally constrain their features, and as a result, analysis methods designed for social networks typically fail to capture useful characteristics or make informative comparisons. In the case of road networks, natural constraints on the edge distribution weaken the ability of standard co...

This chapter illustrates how philosophy and political science can inform one another by providing an overview of philosophical contributions the authors have made on the topic of political polarization. The authors outline three contributions they have made to understanding political polarization, particularly of the epistemic kind, discussing work...

Compared to social and information networks, the geospatial characteristics of transportation networks make them structurally constrained. Although road, flight, train, and other such networks have been analyzed using social network analysis methods, the results typically fail to capture useful characteristics or make informative comparisons. In th...

Walkability analyses have recently gained attention for economic, health, and environmental reasons [5, 8, 13]. We examine the walkable store profiles for train stations of central Tokyo and use machine learning to find clusters of similarly walkable areas. First, we use a breadth-first search algorithm on the road network to determine the walkable...

Walkability analyses have gained increased attention for economic, environmental and health reasons, but the methods for assessing walkability have yet to be broadly evaluated. In this paper, five methods for calculating walkability scores are described: in-radius, circle buffers, road network node buffers, road network edge buffers and a fully int...

The present research investigates how psychological mechanisms and social network structures generate patterns of cultural change and diversity. The two psychological mechanisms studied here are cultural drift and indirect minority influence; the former is parameterized by an error rate (ε) and the latter by a leniency threshold (λ). The patterns o...

We motivate a picture of social epistemology that sees forgetting as subject to epistemic evaluation. Using computer simulations of a simple agent-based model, we show that how agents forget can have as large an impact on group epistemic outcomes as how they share information. But, how we forget, unlike how we form beliefs, isn’t typically taken to...

We apply variations and extensions of structural balance theory to analyze the dynamics of geopolitical relations using data from the virtual world Eve Online . The highly detailed data enable us to study the interplay of alliance size, power, and geographic proximity on the prevalence and conditional behavior of triads built from empirical politic...

Transportation networks allow us to model flows of people and resources across geographic space, but the people and resources we wish to model are often not natively tied to our networks. Instead, they can occur as point data (such as store, train station, and domicile locations) and/or grid data (such as socio-economic and aggregate area data). He...

This is an extension from a selected paper from JSAI2019. Understanding accessibility in its many forms requires merging multimodal transportation network analysis with geospatial socioeconomic data and novel measures of their interaction. Building on previous research that scored and classified 500 random points within the Greater Tokyo Area, we n...

Abstract We model the flow of human capital and resources across multimodal transportation networks throughout the Greater Tokyo Area. Our transportation networks include trains, buses, and roads integrated with a walking network among a geographically grounded hexagonal grid and connecting nodes of different modes. The hexagonal grid holds data on...

In order to better understand the role of transportation convenience in location preferences, as well as to uncover transportation system patterns that span multiple modes of transportation, we analyze 500 locations in the Tokyo area using properties of their multimodal transportation networks. Multiple sets of measures are used to cluster regions...

Public discussions of political and social issues are often characterized by deep and persistent polarization. In social psychology, it’s standard to treat belief polarization as the product of epistemic irrationality. In contrast, we argue that the persistent disagreement that grounds political and social polarization can be produced by epistemica...

In the original publication of the article, the Acknowledgement section was inadvertently not included. The Acknowledgement is given in this Correction.

Complex systems are characterized by processes that exhibit feedback, nonlinearity, heterogeneity, and path dependencies, and accurately modeling such systems is becoming increasing important. To help realize the potential of complex systems modeling we need new methods that are capable of capturing the dynamical properties of such processes across...

This article aims to describe the last 10 years of the collaborative scientific endeavors on polarization in particular and collective problem-solving in general by our multidisciplinary research team. We describe the team's disciplinary composition-social psychology, political science, social philosophy/epistemology, and complex systems science-hi...

Concepts and measures of time series uncertainty and complexity have been applied across domains for behavior classification, risk assessments, and event detection/prediction. This paper contributes three new measures based on an encoding of the series' phase space into a descriptive Markov model. Here we describe constructing this kind of “Reveale...

Epistemic justifications for democracy have been offered in terms of two different forms of information aggregation and decision-making. The Condorcet Jury Theorem is appealed to as a justification in terms of votes, and the Hong–Page ‘diversity trumps ability’ result is appealed to as a justification in terms of deliberation in the form of collabo...

Structural balance in social network theory starts from signed networks with active relationships (friendly or hostile) to establish a hierarchy between four different types of triadic relationships. The lack of an active link also provides information about the network. To exploit the information that remains uncovered by structural balance, we in...

According to hedonic pricing theory (HPT) market forces operate on individual characteristics of a good, and the price of a product is the aggregate of the price across those characteristics. The relationship between price and characteristics remains poorly understood because characteristic qualities are hard to quantify, people have varying levels...

According to hedonic pricing theory (HPT) market forces operate on individual characteristics of a good, and the price of a product is the aggregate of the price across those characteristics. The relationship between price and characteristics remains poorly understood because characteristic qualities are hard to quantify, people have varying levels...

Supplementary text. The full dataset used and additional details of our analysis results (including Fig S1 and reference 48). (PDF)

The present research investigates whether and how different the emergent patterns of group change and diversity within a group produced by indirect minority influence and random errors. We compare two mechanisms (a) random errors (Bednar, Bramson, Jones-Rooy, & Page, 2010; Nowak & Lewenstein, 1996) and (b) indirect minority influence (Jung, Bramson...

The Hong and Page ‘diversity trumps ability’ result has been used to argue for the more general claim that a diverse set of agents is epistemically superior to a comparable group of experts. Here we extend Hong and Page’s model to landscapes of different degrees of randomness and demonstrate the sensitivity of the ‘diversity trumps ability’ result....

Structural balance in social network theory starts from signed networks with active relationships (friendly or hostile) to establish a hierarchy between four different types of triadic relationships. The lack of an active link also provides information about the network. To exploit the information that remains uncovered by structural balance, we in...

Diversität und Demokratie: Agent-Based Modelling in der politischen Philosophie: Agent-based models have played a prominent role in recent debates about the merits of democracy. In particular, the formal model of Lu Hong and Scott Page and the associated "diversity trumps ability" result has typically been seen to support the epistemic virtues of d...

The present paper describes an agent-based model of indirect minority influence. It examines whether indirect minority influence can lead to social change as a function of cognitive rebalancing, a process whereby related attitudes are affected when one attitude is changed. An attitude updating algorithm was modelled with minimal assumptions drawing...

We present a form of temporal network called a “temporal web” that connects nodes across time into a single temporally extended acyclic directed graph as a way to capture contingent behaviors. This representation is especially useful for uncovering and measuring social influence. We first present the general temporal web technique and then use it t...

Triadic relationships are accepted to play a key role in the dynamics of social and political networks. Building on insights gleaned from balance theory in social network studies and from Boltzmann-Gibbs statistical physics, we propose a model to quantitatively capture the dynamics of the four types of triadic relationships in a network. Central to...

Polarization is a topic of intense interest among social scientists, but there is significant disagreement regarding the character of the phenomenon and little understanding of underlying mechanics. A first problem, we argue, is that polarization appears in the literature as not one concept but many. In the first part of the article, we distinguish...

The present paper proposes an agent-based model of indirect minority influence to examine a theoretical assumption that indirect minority influence leads to social change as a function of cognitive rebalancing. An attitude updating algorithm was constructed with minimal assumptions based on social psychological theories on indirect minority influen...

This article distinguishes nine senses of polarization and provides formal measures for each one to refine the methodology used to describe polarization in distributions of attitudes. Each distinct concept is explained through a definition, formal measures, examples, and references. We then apply these measures to GSS data regarding political views...

Identifying key agents for the transmission of diseases (ideas, technology, etc.) across social networks has predominantly relied on measures of centrality on a static base network or a temporally flattened graph of agent interactions. Various measures have been proposed as the best trackers of influence, such as degree centrality, betweenness, and...

Network dynamics are typically presented as a time series of network properties captured at each period. The current approach examines the dynamical properties of transmission via novel measures on an integrated, temporally extended network representation of interaction data across time. Because it encodes time and interactions as network connectio...

A scientific community can be modeled as a collection of epistemic agents attempting to answer questions, in part by communicating about their hypotheses and results. We can treat the pathways of scientific communication as a network. When we do, it becomes clear that the interaction between the structure of the network and the nature of the questi...

Ryall and Bramson's Inference and Intervention is the first textbook on causal modeling with Bayesian networks for business applications. In a world of resource scarcity, a decision about which business elements to control or change – as the authors put it, a managerial intervention – must precede any decision on how to control or change them, and...

The current project introduces a general theory and supporting models that offer a plausible explanation and viable mechanism for generating and perpetuating prosocial behavior. The proposed mechanism is preferential detachment and the theory proposed is that agents utilizing preferential detachment will sort themselves into social arrangements suc...

Empirical evidence demonstrates that cultures exist, they differ from one another, they're coherent and yet diversity persists within them. In this paper, we describe a multi-dimensional model of cultural formation that produces all of these properties. Our model includes two forces: an internal desire to be consistent and social pressure to confor...

Game theoretic models and computer simulations of the evolution of cooperation, coordination, culture, morality, and norms have played a significant role in the advancement of our understanding of how individual actions under differing incentive schemes produce different aggregated outcomes. This project presents preliminary results of extending ex...

To help realize the potential of complex systems models we need new measures appropriate for capturing processes that exhibit feedback, nonlinearity, heterogeneity, and emergence. As part of a larger research project encompassing several categories of dynamical properties this paper provides formal and general definitions of tipping point-related p...

This paper draws distinctions among various concepts related to tipping points, robustness, path dependence, and other properties of system dynamics. For each concept a formal definition is provided that utilizes Markov model representations of systems. We start with the basic features of Markov models and definitions of the foundational concepts o...

In this paper, we construct a simple model that simultaneously produces inter cultural heterogeneity, distinct cultural signatures, and intra cultural heterogeneity. Our model assumes only that people pursue both consistency and conformity. We show that these two incentives produce distinct, diverse cultures but because they partially work at cross...

This paper presents a generalized methodology for propagating known or estimated levels of individual source document truth reliability to determine the confidence level of a combined output. Initial document certainty levels are augmented by (i) combining the reliability measures of multiply sources, (ii) incorporating the truth reinforcement of r...

In order to better understand whether heuristics can comprise a normative decision theory I first explore some common support for heuristics and comment against their importance for the normative questions. Then I examine the role that any normative theory must fill and how we can evaluate and compare them. I conclude (tentatively) that normativity...

Hartry Field, in his famous 1972 paper, criticizes Alfred Tarski's work on truth on three important points. He (i) suggests using sentence tokens instead of sentence types as the primary truth bearers, (ii) thinks the need to change the truth theory for every change in vocabulary is undesirable, and (iii) claims that Tarski merely provides an elimi...

Let us chace our imagination to the heavens, or to the utmost limits of the universe; we never really advance a step beyond ourselves, nor can conceive any kind of existence, but those perceptions, which have appear'd in that narrow compass. This is the universe of the imagination, nor have we any idea but what is there produc'd. -Hume (Treatise I....

Moral theories typically rest upon the assumption that conscious deliberation plays a causal role in action; however, a growing body of scientific evidence supports a physi-calist account of causation that leaves no causal role for mental activity. In response, I develop a moral theory (including moral truth, motivation, and meaning) that excludes...