Voter opinion dynamics of science

1 collaborator

Duncan Law (Author)

WHAT IS IT?

A simple opinion dynamics model of scientific belief formation and dissemination.

HOW IT WORKS

The underlying state of nature is '1'. Agents in the model can have one of two states: belief that the underlying state of nature is either 1 or 0.

There are three categories of agent in the model: scientists, citizens, and fanatics. Scientists inhabit an 'invisible college' surrounded by a 'public sphere' of citizens. Fantatics are randomly distributed among citizens; there are no fanatic scientists.

In each round of play:

Scientists can observe either nature or the belief of one of their neighbours. If they observe nature, they may observe it correctly or incorrectly. They then update their own opinion to mimic their observation.

Citizens observe the belief of one of their neighbours. They then update their opinion to mimic that observed opinion.

Fanatics make no observations. Their opinions remain static.

HOW TO USE IT

The 'worldside' slider determines the size of the world and thus the number of agents.

The 'collegeside' slider determines the size of the invisible college of scientists, represented by dots.

The 'proportionfanatics' slider determines the percentage of agents within the 'public sphere' who are fantatics, represented by circles.

Non-fanatic members of the public sphere are citizens, represented by 'x's.

The 'observe' slider determines the probability of a scientist observing nature in any given round of play.

The 'experimentsuccess' slider determines the probability of any given scientist's observation of nature accurately observing the true underlying state of nature.

The 'startingopinions' slider determines the likelihood of any given agent believing that the state of nature is 0, on setup.

Agents who believe that the underlying state of nature is 1 are green; agents who believe that the underlying state of nature is 0 are blue.

Fanatics will all believe that the state of nature is 0, regardless of the other parameters of the model.

CREDITS AND REFERENCES

The model is described and discussed in more detail in:

Law, Duncan (2019), 'The reputational economics of open inputs science', Ph.D. thesis.

COPYRIGHT AND LICENSE

This work is licensed under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 License. To view a copy of this license, visit https://creativecommons.org/licenses/by-nc-sa/3.0/ or send a letter to Creative Commons, 559 Nathan Abbott Way, Stanford, California 94305, USA.

Comments and Questions

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Click to Run Model

breed [scientists scientist]
breed [citizens citizen]
breed [fanatics fanatic]
globals [dummy xdummy ydummy totalweight numerator dummy2 observation]
turtles-own [opinion]
links-own [weight]

to setup

  set-default-shape scientists "dot"
  set-default-shape citizens "x"
  set-default-shape fanatics "circle"

  clear-all

  resize-world 0 (worldside - 1) 0 (worldside - 1)

  reset-ticks

  ask patches [

    ifelse ( ( pycor >= ( worldside - collegeside ) ) AND ( pxcor < collegeside ) )

    [ sprout-scientists 1 ]
    [ ifelse random 100 < proportionfanatics
      [ sprout-fanatics 1 ]
      [ sprout-citizens 1 ]
    ]

  ]

  ;; The following assigns starting opinions to the scientists

  ask turtles [
    ifelse ( random 100 < startingopinions )
    [ set opinion 0
      set color blue ]
    [ set opinion 1
      set color green ]
  ]

  ask fanatics [
    set opinion 0
    set color blue ]

  ;; The following creates the links

  ask turtles [
    create-links-with turtles-at 0 -1 [ set weight 100 ]
    create-links-with turtles-at -1 0 [ set weight 100 ]
  ]
end 

to addone

  set dummy ( dummy + 1 )
end 

to go

  ask turtles [

  ifelse random 100 < experimentsuccess
    [ set observation 1 ]
    [ set observation 0 ]


  set totalweight 0
  ask my-links [ set totalweight ( totalweight + weight ) ]

  set dummy2 0
  set numerator random totalweight


  ask my-links [
    if ( ( dummy2 <= numerator ) AND ( numerator < ( dummy2 + weight ) ) ) [ set dummy ( [opinion] of other-end ) ]
    set dummy2 (dummy2 + weight)
  ]

  if breed = scientists
  [ if random 100 < observe
    [ set dummy observation ]
  ]

  if breed = fanatics
  [ set dummy 0 ]

  set opinion dummy



  ifelse opinion = 0
  [set color blue]
  [set color green]


  ]


  tick
end

There is only one version of this model, created over 5 years ago by Duncan Law.

Attached files

File	Type	Description	Last updated
Voter opinion dynamics of science.png	preview	Preview for 'Voter opinion dynamics of science'	over 5 years ago, by Duncan Law	Download

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