Papers by Christopher Reade
A scientific community can be modeled as a collection of epistemic agents attempting to answer qu... more 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 question under investigation affects epistemic desiderata, including accuracy and speed to community consensus. Here we build on previous work, both our own and others', in order to get a firmer grasp on precisely which features of scientific communities interact with which features of scientific questions in order to influence epistemic outcomes.
It is widely accepted that the way information transfers across
networks depends importantly on ... more It is widely accepted that the way information transfers across
networks depends importantly on the structure of the network.
Here, we show that the mechanism of information transfer is
crucial: in many respects the effect of the specific transfer
mechanism swamps network effects. Results are demonstrated
in terms of three different types of transfer mechanism: germs,
genes, and memes. With an emphasis on the specific case of
transfer between sub-networks, we explore both the dynamics
of each of these across networks and a measure of their
comparative fitness.
Germ and meme transfer exhibit very different dynamics
across linked networks. For germs, measured in terms of time
to total infection, network type rather than degree of linkage
between sub-networks is the primary factor. For memes or
belief transfer, measured in terms of time to consensus, it is the
opposite: degree of linkage trumps network type in importance.
The dynamics of genetic information transfer is unlike either
germs or memes. Transfer of genetic information is robust
across network differences to which both germs and memes
prove sensitive.
We also consider function: how well germ, gene, and meme
transfer mechanisms can meet their respective objectives of
infecting the population, mixing and transferring genetic
information, and spreading a message. A shared formal
measure of fitness is introduced for purposes of comparison,
again with an emphasis on linked sub-networks. Meme
transfer proves superior to transfer by genetic reproduction on
that measure, with both memes and genes superior to infection
dynamics across all networks types. What kinds of network
structure optimize fitness also differ among the three. Both
germs and genes show fairly stable fitness with added links
between sub-networks, but genes show greater sensitivity to the
structure of sub-networks at issue. Belief transfer, in contrast to
the other two, shows a clear decline in fitness with increasingly
connected networks.
When it comes to understanding how information moves on
networks, our results indicate that questions of information
dynamics on networks cannot be answered in terms of networks
alone. A primary role is played by the specific mechanism of
information transfer at issue. We must first ask about how a
particular type of information moves.
Public health care interventions-regarding vaccination, obesity, and HIV, for example-standardly ... more Public health care interventions-regarding vaccination, obesity, and HIV, for example-standardly take the form of information dissemination across a community. But information networks can vary importantly between different ethnic communities, as can levels of trust in information from different sources. We use data from the Greater Pittsburgh Random Household Health Survey to construct models of information networks for White and Black communities-models which reflect the degree of information contact between individuals, with degrees of trust in information from various sources correlated with positions in that social network. With simple assumptions regarding belief change and social reinforcement, we use those modeled networks to build dynamic agent-based models of how information can be expected to flow and how beliefs can be expected to change across each community. With contrasting information from governmental and religious sources, the results show importantly different dynamic patterns of belief polarization within the two communities.
A scientific community can be modeled as a collection of epistemic agents attempting to answer qu... more 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 question under investigation affects epistemic desiderata, including accuracy and speed to community consensus. Here we build on previous work, both our own and others', in order to get a firmer grasp on precisely which features of scientific communities interact with which features of scientific questions in order to influence epistemic outcomes.
Philosophy of Science, 2015
ABSTRACT Understanding the dynamics of information is crucial to many areas of research, both ins... more ABSTRACT Understanding the dynamics of information is crucial to many areas of research, both inside and outside of philosophy. Using computer simulations of three kinds of information, germs, genes, and memes, we show that the mechanism of information transfer often swamps network structure in terms of its effects on both the dynamics and the fitness of the information. This insight has both obvious and subtle implications for a number of questions in philosophy, including questions about the nature of information, whether there is genetic information, and how to arrange scientific communities.
Connections (Toronto, Ont.), 2010
In order to understand the transmission of a disease across a population we will have to understa... more In order to understand the transmission of a disease across a population we will have to understand not only the dynamics of contact infection but the transfer of health-care beliefs and resulting health-care behaviors across that population. This paper is a first step in that direction, focusing on the contrasting role of linkage or isolation between sub-networks in (a) contact infection and (b) belief transfer. Using both analytical tools and agent-based simulations we show that it is the structure of a network that is primary for predicting contact infection-whether the networks or sub-networks at issue are distributed ring networks or total networks (hubs, wheels, small world, random, or scale-free for example). Measured in terms of time to total infection, degree of linkage between sub-networks plays a minor role. The case of belief is importantly different. Using a simplified model of belief reinforcement, and measuring belief transfer in terms of time to community consensus, ...
Abstract In this paper we make a simple theoretical point using a practical issue as an example. ... more Abstract In this paper we make a simple theoretical point using a practical issue as an example. The simple theoretical point is that robustness is not'all or nothing': in asking whether a system is robust one has to ask'robust with respect to what property?'and'robust ...
ABSTRACT Beyond belief change and meme adoption, both genetics and infection have been spoken of ... more ABSTRACT Beyond belief change and meme adoption, both genetics and infection have been spoken of in terms of information transfer. What we examine here, concentrating on the specific case of transfer between sub-networks, are the differences in network dynamics in these cases: the different network dynamics of germs, genes, and memes. Germs and memes, it turns out, exhibit a very different dynamics across networks. For infection, measured in terms of time to total infection, it is network type rather than degree of linkage between sub-networks that is of primary importance. For belief transfer, measured in terms of time to consensus, it is degree of linkage rather than network type that is crucial. Genes model each of these other dynamics in part, but match neither in full. For genetics, like belief transfer and unlike infection, network type makes little difference. Like infection and unlike belief, on the other hand, the dynamics of genetic information transfer within single and between linked networks are much the same. In ways both surprising and intriguing, transfer of genetic information seems to be robust across network differences crucial for the other two.
Public health care interventions-regarding vaccination, obesity, and HIV, for example-standardly ... more Public health care interventions-regarding vaccination, obesity, and HIV, for example-standardly take the form of information dissemination across a community. But information networks can vary importantly between different ethnic communities, as can levels of trust in information from different sources. We use data from the Greater Pittsburgh Random Household Health Survey to construct models of information networks for White and Black communities--models which reflect the degree of information contact between individuals, with degrees of trust in information from various sources correlated with positions in that social network. With simple assumptions regarding belief change and social reinforcement, we use those modeled networks to build dynamic agent-based models of how information can be expected to flow and how beliefs can be expected to change across each community. With contrasting information from governmental and religious sources, the results show importantly different dynamic patterns of belief polarization within the two communities.
A scientific community can be modeled as a collection of epistemic agents attempting to answer qu... more 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 question under investigation affects epistemic desiderata, including accuracy and speed to community consensus. Here we build on previous work, both our own and others', in order to get a firmer grasp on precisely which features of scientific communities interact with which features of scientific questions in order to influence epistemic outcomes.
It is widely accepted that the way information transfers across networks depends importantly on t... more It is widely accepted that the way information transfers across networks depends importantly on the structure of the network. Here, we show that the mechanism of information transfer is crucial: in many respects the effect of the specific transfer mechanism swamps network effects. Results are demonstrated in terms of three different types of transfer mechanism: germs, genes, and memes. With an emphasis on the specific case of transfer between sub-networks, we explore both the dynamics of each of these across networks and a measure of their comparative fitness.
Germ and meme transfer exhibit very different dynamics across linked networks. For germs, measured in terms of time to total infection, network type rather than degree of linkage between sub-networks is the primary factor. For memes or belief transfer, measured in terms of time to consensus, it is the opposite: degree of linkage trumps network type in importance.
The dynamics of genetic information transfer is unlike either germs or memes. Transfer of genetic information is robust across network differences to which both germs and memes prove sensitive.
We also consider function: how well germ, gene, and meme transfer mechanisms can meet their respective objectives of infecting the population, mixing and transferring genetic information, and spreading a message. A shared formal measure of fitness is introduced for purposes of comparison, again with an emphasis on linked sub-networks. Meme transfer proves superior to transfer by genetic reproduction on that measure, with both memes and genes superior to infection dynamics across all networks types. What kinds of network structure optimize fitness also differ among the three. Both germs and genes show fairly stable fitness with added links between sub-networks, but genes show greater sensitivity to the structure of sub-networks at issue. Belief transfer, in contrast to the other two, shows a clear decline in fitness with increasingly connected networks.
When it comes to understanding how information moves on networks, our results indicate that questions of information dynamics on networks cannot be answered in terms of networks alone. A primary role is played by the specific mechanism of information transfer at issue. We must first ask about how a particular type of information moves.
Philosophical Computation by Christopher Reade
AAAI Symposium on Complex Adaptive Systems, 2010
In this paper we make a simple theoretical point using a practical issue as an example. The simpl... more In this paper we make a simple theoretical point using a practical issue as an example. The simple theoretical point is that robustness is not 'all or nothing': in asking whether a system is robust one has to ask 'robust with respect to what property?' and 'robust over what set of changes in the system?' The practical issue used to illustrate the point is an examination of degrees of linkage between sub-networks and a pointed contrast in robustness and fragility between the dynamics of (1) contact infection and (2) information transfer or belief change. Time to infection across linked sub-networks, it turns out, is fairly robust with regard to the degree of linkage between them. Time to infection is fragile and sensitive, however, with regard to the type of sub-network involved: total, ring, small world, random, or scale-free. Aspects of robustness and fragility are reversed where it is belief updating with reinforcement rather than infection that is at issue. In information dynamics, the pattern of time to consensus is robust across changes in network type but remarkably fragile with respect to degree of linkage between sub-networks. These results have important implications for public health interventions in realistic social networks, particularly with an eye to ethnic and socioeconomic sub-communities, and in social networks with sub-communities changing in structure or linkage.
Proceedings, AIII Fall Symposium on Complex Adaptive Systems, 2011
Beyond belief change and meme adoption, both genetics and infection have been spoken of in terms ... more Beyond belief change and meme adoption, both genetics and infection have been spoken of in terms of information transfer. What we examine here, concentrating on the specific case of transfer between sub-networks, are the differences in network dynamics in these cases: the different network dynamics of germs, genes, and memes. Germs and memes, it turns out, exhibit a very different dynamics across networks. For infection, measured in terms of time to total infection, it is network type rather than degree of linkage between sub-networks that is of primary importance. For belief transfer, measured in terms of time to consensus, it is degree of linkage rather than network type that is crucial. Genes model each of these other dynamics in part, but match neither in full. For genetics, like belief transfer and unlike infection, network type makes little difference. Like infection and unlike belief, on the other hand, the dynamics of genetic information transfer within single and between linked networks are much the same. In ways both surprising and intriguing, transfer of genetic information seems to be robust across network differences crucial for the other two.
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Papers by Christopher Reade
networks depends importantly on the structure of the network.
Here, we show that the mechanism of information transfer is
crucial: in many respects the effect of the specific transfer
mechanism swamps network effects. Results are demonstrated
in terms of three different types of transfer mechanism: germs,
genes, and memes. With an emphasis on the specific case of
transfer between sub-networks, we explore both the dynamics
of each of these across networks and a measure of their
comparative fitness.
Germ and meme transfer exhibit very different dynamics
across linked networks. For germs, measured in terms of time
to total infection, network type rather than degree of linkage
between sub-networks is the primary factor. For memes or
belief transfer, measured in terms of time to consensus, it is the
opposite: degree of linkage trumps network type in importance.
The dynamics of genetic information transfer is unlike either
germs or memes. Transfer of genetic information is robust
across network differences to which both germs and memes
prove sensitive.
We also consider function: how well germ, gene, and meme
transfer mechanisms can meet their respective objectives of
infecting the population, mixing and transferring genetic
information, and spreading a message. A shared formal
measure of fitness is introduced for purposes of comparison,
again with an emphasis on linked sub-networks. Meme
transfer proves superior to transfer by genetic reproduction on
that measure, with both memes and genes superior to infection
dynamics across all networks types. What kinds of network
structure optimize fitness also differ among the three. Both
germs and genes show fairly stable fitness with added links
between sub-networks, but genes show greater sensitivity to the
structure of sub-networks at issue. Belief transfer, in contrast to
the other two, shows a clear decline in fitness with increasingly
connected networks.
When it comes to understanding how information moves on
networks, our results indicate that questions of information
dynamics on networks cannot be answered in terms of networks
alone. A primary role is played by the specific mechanism of
information transfer at issue. We must first ask about how a
particular type of information moves.
Germ and meme transfer exhibit very different dynamics across linked networks. For germs, measured in terms of time to total infection, network type rather than degree of linkage between sub-networks is the primary factor. For memes or belief transfer, measured in terms of time to consensus, it is the opposite: degree of linkage trumps network type in importance.
The dynamics of genetic information transfer is unlike either germs or memes. Transfer of genetic information is robust across network differences to which both germs and memes prove sensitive.
We also consider function: how well germ, gene, and meme transfer mechanisms can meet their respective objectives of infecting the population, mixing and transferring genetic information, and spreading a message. A shared formal measure of fitness is introduced for purposes of comparison, again with an emphasis on linked sub-networks. Meme transfer proves superior to transfer by genetic reproduction on that measure, with both memes and genes superior to infection dynamics across all networks types. What kinds of network structure optimize fitness also differ among the three. Both germs and genes show fairly stable fitness with added links between sub-networks, but genes show greater sensitivity to the structure of sub-networks at issue. Belief transfer, in contrast to the other two, shows a clear decline in fitness with increasingly connected networks.
When it comes to understanding how information moves on networks, our results indicate that questions of information dynamics on networks cannot be answered in terms of networks alone. A primary role is played by the specific mechanism of information transfer at issue. We must first ask about how a particular type of information moves.
Philosophical Computation by Christopher Reade
networks depends importantly on the structure of the network.
Here, we show that the mechanism of information transfer is
crucial: in many respects the effect of the specific transfer
mechanism swamps network effects. Results are demonstrated
in terms of three different types of transfer mechanism: germs,
genes, and memes. With an emphasis on the specific case of
transfer between sub-networks, we explore both the dynamics
of each of these across networks and a measure of their
comparative fitness.
Germ and meme transfer exhibit very different dynamics
across linked networks. For germs, measured in terms of time
to total infection, network type rather than degree of linkage
between sub-networks is the primary factor. For memes or
belief transfer, measured in terms of time to consensus, it is the
opposite: degree of linkage trumps network type in importance.
The dynamics of genetic information transfer is unlike either
germs or memes. Transfer of genetic information is robust
across network differences to which both germs and memes
prove sensitive.
We also consider function: how well germ, gene, and meme
transfer mechanisms can meet their respective objectives of
infecting the population, mixing and transferring genetic
information, and spreading a message. A shared formal
measure of fitness is introduced for purposes of comparison,
again with an emphasis on linked sub-networks. Meme
transfer proves superior to transfer by genetic reproduction on
that measure, with both memes and genes superior to infection
dynamics across all networks types. What kinds of network
structure optimize fitness also differ among the three. Both
germs and genes show fairly stable fitness with added links
between sub-networks, but genes show greater sensitivity to the
structure of sub-networks at issue. Belief transfer, in contrast to
the other two, shows a clear decline in fitness with increasingly
connected networks.
When it comes to understanding how information moves on
networks, our results indicate that questions of information
dynamics on networks cannot be answered in terms of networks
alone. A primary role is played by the specific mechanism of
information transfer at issue. We must first ask about how a
particular type of information moves.
Germ and meme transfer exhibit very different dynamics across linked networks. For germs, measured in terms of time to total infection, network type rather than degree of linkage between sub-networks is the primary factor. For memes or belief transfer, measured in terms of time to consensus, it is the opposite: degree of linkage trumps network type in importance.
The dynamics of genetic information transfer is unlike either germs or memes. Transfer of genetic information is robust across network differences to which both germs and memes prove sensitive.
We also consider function: how well germ, gene, and meme transfer mechanisms can meet their respective objectives of infecting the population, mixing and transferring genetic information, and spreading a message. A shared formal measure of fitness is introduced for purposes of comparison, again with an emphasis on linked sub-networks. Meme transfer proves superior to transfer by genetic reproduction on that measure, with both memes and genes superior to infection dynamics across all networks types. What kinds of network structure optimize fitness also differ among the three. Both germs and genes show fairly stable fitness with added links between sub-networks, but genes show greater sensitivity to the structure of sub-networks at issue. Belief transfer, in contrast to the other two, shows a clear decline in fitness with increasingly connected networks.
When it comes to understanding how information moves on networks, our results indicate that questions of information dynamics on networks cannot be answered in terms of networks alone. A primary role is played by the specific mechanism of information transfer at issue. We must first ask about how a particular type of information moves.