Child of Version_20250923-1_Spread of Opinions Influenced by Group Effects and reward plus metablock
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WHAT IS IT?
This simulator was developed from research by the Public Opinion Research Group.
It models how opinions on political or social issues spread inside a population, using a multi-agent system.
The first applications focused on modelling the Quebec electorate facing political issues. Surveys revealed a close relationship between voters’ bias level on these issues and the importance of internal representations (or “memes”) underlying their adhesion or rejection.
The simulator reproduces how such bipolar opinions spread and evolve in a connected population.
Agents represent individuals, each carrying: - an opinion (from −1 = strongly against to +1 = strongly in favour), - a prevalence (strength/salience of internal representations), - an influence (capacity to convince others), - and a set of social links.
The model studies the co-evolution of: 1. Individual convictions (opinions), 2. Prevalence (depth/number of representations), 3. Influence (convincing power), 4. Social network structure.
HOW TO USE IT
General operation
- Choose the population size with
pop
. - Press Setup to create agents and their initial links. Background is set to black.
- Press Go to run or pause the simulation.
3D Representation
- X axis: opinion (−1 left, +1 right),
- Y axis: prevalence (0–99),
- Z axis: influence (0–1).
Agents are coloured:
- Blue → right-leaning opinion,
- Red → left-leaning opinion,
- Yellow → meta-influencers.
Links (ties) are coloured:
- Green → agents with same opinion sign,
- Gray → opposite signs.
USER INTERFACE CONTROLS
1. General controls
- Setup: initialize agents and network.
- Go: start or stop simulation.
- in_file: load agent states from a file.
- refresh / cumulative: control graph refresh and whether stats reset or accumulate.
2. Population and iterations
pop
: number of agents.nb_try
,max_iter
,threshold
: govern experiment length and repetitions.choice_iter
: select iteration when replaying from file.
3. Social network dynamics
Links evolve as opinions shift:
- link-removal-threshold
: max opinion distance above which links may be cut.
- link-formation-threshold
: max distance to allow new links.
- prob
: probability applied to link creation/removal.
- linksdown
: max number of links removed per tick.
- linksup
: max number of links created per tick.
- bridge-prob
: probability to create “bridges” across opposing camps.
4. Meta-influencers
Special agents with very high influence (fixed at 1).
- meta-influencers-selection
: choose scope (All, Left, Right).
- meta-influencers
: proportion of population to turn into meta-influencers.
- prev-low
/ prev-high
: restrict eligible prevalence.
- meta-links
, meta-min
, meta-max
: number of links meta-influencers maintain.
- meta-ok
: toggle their presence.
- vary-influence
: if ON, influence grows with successful transmissions and decreases with failures.
- metablock
: if ON, prevents meta-influencers from changing opinion polarity (sign).
5. Opinion dynamics
Prevalence and influence
rate-infl
: speed at which influence changes after adoption.modulation-prevalence
andrate-modulation
: adjust prevalence as opinions shift.noise
: probability of random opinion drift.polarization-factor
: reduces adoption probability for large opinion gaps.
Adoption probabilities
prevalence-weight
(0–2 typical): how strongly prevalence gap matters.adoption-floor
(0–0.1 typical): minimal adoption probability, even for distant opinions.
6. Group impact
Group alignment modulates adoption probability.
group-impact-mode
:- all → considers all linked neighbours.
- k-nearest → only the closest
k
neighbours in opinion space.
- all → considers all linked neighbours.
group-k
(1 to number of neighbours): number of neighbours used when k-nearest is active.group-impact-weight
(0–1): strength of group effect.group-impact-alpha
(0.2–3 typical): non-linearity.<1
: small aligned groups have strong effect,=1
: linear,>1
: only large aligned majorities matter.
7. Reward mechanism
Agents can gain a bonus when they succeed in influencing a neighbour.
reward-step
(0.01–0.1 typical): increment in transmission bonus.reward-cap
(0.1–1.0 typical): maximum bonus an agent can accumulate.reward-scope
: apply to both camps, left-only, or right-only.reward-prev-delta
(0–5 typical): optional increase of the target’s prevalence after adoption.reward-decay
(0–0.05 typical): gradual loss of bonus over time.
8. Meme-based representation
If use-memes?
is ON, opinions and prevalence derive from two internal stocks of memes:
- meme-plus
: representations supporting positive polarity.
- meme-minus
: representations supporting negative polarity.
Parameters:
- meme-max
: maximum stock of memes (scale of prevalence).
- meme-gain
: increase in memes when influenced.
- meme-anti-leak
(0–1): cross-erosion, reduces opposite stock when one side grows.
- meme-decay
(0–0.05 typical): gradual forgetting.
Opinion is recalculated as the balance between meme-plus
and meme-minus
.
Prevalence reflects the total number of memes held by the agent.
9. External events
Perturb the system through shocks:
- Define bounds (low_meme
, high_meme
, low-prev
, high-prev
).
- Apply event_size
(opinion shift) and prev_change
(prevalence shift).
- Trigger manually with Event button or automatically via auto_event
+ tick-event
.
OUTPUTS
Monitors
Show in real time:
- % of left / right,
- medians of opinion, prevalence, influence,
- inversions, interactions, fractal dimension,
- links created/removed.
Graph
Tracks the evolution of population distributions and variables over time.
CSV Export
If csv-export
is ON, results are saved per trial with a standardized header.
THINGS TO NOTICE
- How opinions converge, polarize, or remain fragmented.
- The role of meta-influencers, group alignment, and reward mechanisms.
- The impact of memes when enabled.
- How link dynamics (green vs gray) structure the debate.
CREDITS
- Original concept: Public Opinion Research Group
- NetLogo implementation & enhancements: Pierre-Alain Cotnoir (2015–2025)
- AI-assisted design: GPT-4 & GPT-5 (2024-2025)
- Contact: pacotnoir@gmail.com
QUICK REFERENCE — CHEAT SHEET
This page summarizes the main controls of the simulator for non-specialists.
Each slider/switch/button is grouped by theme, with recommended value ranges and the effects on the simulation.
Population & Iterations
- pop → number of agents.
- nbtry, maxiter, threshold → control repetitions and stopping criteria.
- choice_iter → load from saved file at selected iteration.
Social Network
- link-removal-threshold (0–1.0) → above this gap, links may be cut.
- link-formation-threshold (0–1.0) → below this gap, links may form.
- prob (0–1.0) → probability for link creation/removal each tick.
- linksdown / linksup (1–50 typical) → caps on removals/creations per tick.
- bridge-prob (0–0.3) → chance of links between opposing camps.
- ↑ value = more bridges, more sign reversals.
Meta-influencers
- meta-influencers-selection → All / Left / Right.
- meta-influencers (0–30%) → proportion of metas.
- prev-low / prev-high → restrict by prevalence.
- meta-links, meta-min, meta-max → control number of links per meta.
- meta-ok → enable metas.
- vary-influence → metas gain influence when successful, lose it when not.
- metablock → if ON, metas cannot switch sign (they stay Left or Right).
Opinion & Prevalence
- rate-infl (0–0.1 typical) → speed of influence updates.
- modulation-prevalence → ON to adjust prevalence with opinion changes.
- rate-modulation (0–1.0) → how fast prevalence adapts.
- noise (0–0.1) → probability of random opinion drift.
- polarization-factor (0–1.0) → reduces adoption across large opinion gaps.
- prevalence-weight (0–2) → stronger role of prevalence differences.
- adoption-floor (0–0.1) → minimal chance of adoption, even across divides.
Group Impact
- group-impact-mode → all neighbours or k-nearest.
- group-k (1–20 typical) → number of neighbours when in k-nearest mode.
- group-impact-weight (0–1.0) → weight of group effect.
- group-impact-alpha (0.2–3) → non-linearity:
<1
small minorities influence strongly,=1
linear,>1
only large majorities matter.
Reward System
- reward-step (0.01–0.1) → bonus gained after success.
- reward-cap (0.1–1.0) → maximum cumulative bonus.
- reward-scope → both camps / left-only / right-only.
- reward-prev-delta (0–5) → optional increase of target prevalence.
- reward-decay (0–0.05) → gradual loss of accumulated bonus.
Meme-Based Representation (if use-memes?
ON)
- meme-max (50–200 typical) → max stock of memes per agent.
- meme-gain (0.5–2.0) → increment in memes per influence.
- meme-anti-leak (0–0.5) → erosion of the opposite meme stock.
- meme-decay (0–0.05) → forgetting rate.
Opinion = balance of meme-plus
vs meme-minus
.
Prevalence = total memes.
External Events
- lowmeme / highmeme → opinion bounds.
- low-prev / high-prev → prevalence bounds.
- event_size → opinion shift applied.
- prev_change → prevalence shift.
- event button → trigger manually.
- auto_event + tick-event → schedule automatic events.
Display & Outputs
- show-links? → toggle visibility of ties.
- linktick (1–5) → link thickness.
- Monitors → show % left/right, medians, inversions, interactions.
- Graph → track evolution of proportions over time.
- CSV Export → save results if
csv-export
is ON.
QUICK EFFECTS OF KEY SLIDERS
| Slider | Low value effect | High value effect | |----------------------|----------------------------------|--------------------------------| | prevalence-weight | Adoption less tied to prevalence | Prevalence dominates adoption | | adoption-floor | Very few cross-camp adoptions | More random inversions | | bridge-prob | Camps stay separated | Many cross-camp links | | group-impact-weight | Neighbours don’t matter much | Group strongly drives adoption | | group-impact-alpha | Minorities can shift opinions | Only large consensus matters | | reward-step | Slow bonus growth | Fast reinforcement | | reward-decay | Bonus stays long | Bonus fades quickly | | meme-anti-leak | Stocks grow independently | Growth erodes opposite stock |
Comments and Questions
extensions [sound nw] ;; For using sound and Network package globals [ min-prevalence max-prevalence meta-influencers-droit meta-influencers-gauche iter change total inversion try major fractale ordonnee abcisse profondeur list_data file-in in_data repet_data links-dead links-create meta-agents meta-links meta-create Interactions %Major ;; === CSV export === csv-export csv-basename csv-file csv-open? ;; === Paramètres d’inversion / ponts (sliders UI possibles) === ;;prevalence-weight ;; >= 0 ; amplification du rôle de Δprégnance ;;adoption-floor ;; [0..1] ; plancher minimal pour la pénalité de polarisation ;;bridge-prob ;; [0..1] ; probabilité de créer un lien-pont (opinion éloignée) ;; === Paramètres de RÉCOMPENSE (sliders/inputs UI) === ;;reward-step ;; palier d’augmentation du bonus à chaque succès (ex: 0.05) ;;reward-cap ;; plafond du bonus cumulé (ex: 0.50) ;;reward-scope ;; "both" | "left-only" | "right-only" ;;reward-prev-delta ;; hausse de prégnance du ciblé au succès (ex: 0..5), 0 = off ;;reward-decay ;; décroissance du bonus par tick (ex: 0..0.01), 0 = off ] turtles-own [ opinion ;; [-1, 1] prevalence ;; [min-prevalence, max-prevalence] agent-type ;; "Right side" | "Left side" influence ;; [0, 1] opinion-previous influence-previous x3d y3d z3d ;; Mèmes (stock pro/anti) meme-plus meme-minus ;; variables utilitaires old-opinion proposed-opinion ;; Récompense de transmission (bonus multiplicatif p-adopt côté émetteur) tx-bonus ] ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; SETUP ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to setup clear-all set repet_data false set iter 0 set min-prevalence 0 set max-prevalence 99 set-default-shape turtles "person" set try 1 set major 0 set links-dead 0 set links-create 0 set meta-create 0 set meta-agents 0 set change 0 set total 0 set inversion 0 set fractale 0 if vary-influence = true [ set meta-links meta-min ] ;; === Defaults CSV === if not is-boolean? csv-export [ set csv-export false ] if (not is-string? csv-basename) or (csv-basename = "") [ set csv-basename "run" ] set csv-open? false ;; === Defaults IMPACT DE GROUPE === if (not is-string? group-impact-mode) [ set group-impact-mode "all" ] ;; "all" | "k-nearest" if (not is-number? group-k) [ set group-k 10 ] if (not is-number? group-impact-weight) [ set group-impact-weight 0.5 ] if (not is-number? group-impact-alpha) [ set group-impact-alpha 1.0 ] ;; === Default switches === if not is-boolean? show-links? [ set show-links? false ] if not is-boolean? metablock [ set metablock false ] ;; === Defaults inversion/ponts === if (not is-number? prevalence-weight) [ set prevalence-weight 1.5 ] if (not is-number? adoption-floor) [ set adoption-floor 0.02 ] if (not is-number? bridge-prob) [ set bridge-prob 0.10 ] ;; === Defaults REWARD === if not is-number? reward-step [ set reward-step 0.05 ] if not is-number? reward-cap [ set reward-cap 0.50 ] if not is-string? reward-scope [ set reward-scope "both" ] if not is-number? reward-prev-delta [ set reward-prev-delta 0 ] if not is-number? reward-decay [ set reward-decay 0 ] ;; === Defaults MEMES === if not is-boolean? use-memes? [ set use-memes? false ] if not is-number? meme-max [ set meme-max 100 ] if not is-number? meme-gain [ set meme-gain 1.0 ] if not is-number? meme-anti-leak [ set meme-anti-leak 0.0 ] if not is-number? meme-decay [ set meme-decay 0.0 ] set-background-black create rapport end to create ;; Right side create-turtles pop / 2 [ set agent-type "Right side" set opinion random-float 1 ;; (0,1) set color blue set prevalence random-float (opinion * 100) set influence random-float 1 set opinion-previous opinion set influence-previous influence set tx-bonus 0 ;; init mèmes cohérente avec (prevalence, opinion) let tot initial-prevalence-to-memes prevalence ifelse opinion >= 0 [ set meme-plus tot * (0.5 + 0.5 * abs opinion) set meme-minus tot - meme-plus ] [ set meme-minus tot * (0.5 + 0.5 * abs opinion) set meme-plus tot - meme-minus ] update-3d self ] ;; Left side create-turtles pop / 2 [ set agent-type "Left side" set opinion (random-float 1 - 1) ;; (-1,0) set color red set prevalence random-float (abs opinion * 100) set influence random-float 1 set opinion-previous opinion set influence-previous influence set tx-bonus 0 ;; init mèmes cohérente avec (prevalence, opinion) let tot initial-prevalence-to-memes prevalence ifelse opinion >= 0 [ set meme-plus tot * (0.5 + 0.5 * abs opinion) set meme-minus tot - meme-plus ] [ set meme-minus tot * (0.5 + 0.5 * abs opinion) set meme-plus tot - meme-minus ] update-3d self ] ;; Méta-influenceurs initiaux influenceurs reset-ticks set total 0 set change 0 set Interactions 0 set %Major 0 update-networks recolor-links apply-link-visibility end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; SORTIES / RAPPORT ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to rapport if output = "Statistics" [ output-print (word "Try ; " "Iter ; " "Opinion global ; " "Opinion right side ; " "Opinion left side ; " "Prevalence right side ; " "Prevalence left side ; " "Influence right side ; " "Influence left side ; " "Left % ; " "Right % ; " "Links-Remove ; " "Links-Create ; " "Inversion % ; " "change ; " "total ; " "fractale") ] if output = "Values" [ output-print (word "Try ; " "Ticks ; " "Agents ; " "Prevalence ; " "Opinion ; " "Influence ; " "meme droit") ] if output = "File" [ ask turtles [ let pre prevalence let mem opinion let infl influence let ti ticks output-print (word ti " " pre " " mem " " infl) ] ] end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; META-INFLUENCEURS ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to influenceurs ;; All if meta-influencers-selection = "All" [ let k round (count turtles * meta-influencers / 100) if k > 0 [ ask n-of k turtles [ if (prevalence >= prev-low and prevalence <= prev-high) [ set influence 1 set color yellow set meta-agents meta-agents + 1 ] ] ] ] ;; Right side if meta-influencers-selection = "Right side" [ set meta-influencers-droit round (count turtles * meta-influencers / 100) let candidates turtles with [opinion > 0] let k min list meta-influencers-droit count candidates if k > 0 [ ask n-of k candidates [ if (prevalence > prev-low and prevalence <= prev-high) [ set influence 1 set color yellow set meta-agents meta-agents + 1 ] ] ] ] ;; Left side if meta-influencers-selection = "Left side" [ set meta-influencers-gauche round (count turtles * meta-influencers / 100) let candidates turtles with [opinion < 0] let k min list meta-influencers-gauche count candidates if k > 0 [ ask n-of k candidates [ if (prevalence > prev-low and prevalence <= prev-high) [ set influence 1 set color yellow set meta-agents meta-agents + 1 ] ] ] ] end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; OUTILS MÉTA / VETO ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; Un agent est "méta" s'il est jaune OU si son influence vaut 1 to-report meta? report (color = yellow) or (influence = 1) end ;; Change l'opinion en respectant le veto méta quand metablock = true. ;; Solution 1 (renforcement sans inversion) : ;; - si la nouvelle opinion change le signe d’un méta alors que metablock=ON, ;; on conserve le signe ACTUEL et on prend la magnitude MAX(abs(old), abs(new)). to maybe-set-opinion [ new-op ] let old-op opinion let bounded-op max list -1 min list 1 new-op if metablock and meta? and (sign old-op != sign bounded-op) [ let mag max list (abs old-op) (abs bounded-op) set opinion (sign old-op) * mag stop ] set opinion bounded-op end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; BOUCLE PRINCIPALE ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to go ifelse (iter < max_iter) [ if iter > 0 [ set Interactions (total / iter) ] if iter > 0 [ set %Major (major / iter * 100) ] set iter iter + 1 set meta-create 0 if (iter = 1 and csv-export and not csv-open?) [ csv-begin ] if auto_event = true [ if (tick-event = iter) [ event ] ] if meta-ok = true [ meta ] update-opinions if network = true [ update-networks ] recolor-links apply-link-visibility if output = "Statistics" [ let avg-opinion mean [opinion] of turtles let positive-opinion safe-median (turtles with [opinion >= 0]) "opinion" let negative-opinion safe-median (turtles with [opinion < 0]) "opinion" let positive-prevalence (safe-median (turtles with [opinion >= 0]) "prevalence") / 100 let negative-prevalence (safe-median (turtles with [opinion < 0]) "prevalence") / 100 let positive-influence safe-median (turtles with [opinion >= 0]) "influence" let negative-influence safe-median (turtles with [opinion < 0]) "influence" let Left% (count turtles with [opinion < 0]) / (pop / 100) let Right% (count turtles with [opinion >= 0]) / (pop / 100) let ti iter output-print (word try " ; " ti " ; " avg-opinion " ; " positive-opinion " ; " negative-opinion " ; " positive-prevalence " ; " negative-prevalence " ; " positive-influence " ; " negative-influence " ; " Left% " ; " Right% " ; " links-dead " ; " links-Create " ; " inversion " ; " change " ; " total " ; " fractale) ] tick if (change > 1 and total > 1) [ set fractale (ln total) / (ln change) ] if (cumulative = false) [ set change 0 set total 0 ] colorer if (refresh = true) [ if ticks > 200 [ reset-ticks clear-plot ] ] if threshold <= (count turtles with [opinion > 0]) / (pop / 100) [ set major major + 1 ] if csv-export [ csv-row ] ] [ ifelse (try < nb_try) [ if csv-export [ csv-end ] set try try + 1 set major 0 clear-turtles clear-plot set change 0 set total 0 set fractale 0 set meta-links meta-min set iter 0 set links-create 0 set links-dead 0 set meta-create 0 set meta-agents 0 set min-prevalence 0 set max-prevalence 99 ifelse (repet_data = true) [ data ] [ create set meta-links meta-min ] ] [ if csv-export [ csv-end ] sound:play-note "Tubular Bells" 60 64 1 stop ] ] end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; MISE À JOUR DES OPINIONS (effet de groupe + récompenses + mèmes + veto méta) ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to update-opinions ask turtles [ set opinion-previous opinion let target one-of link-neighbors if target != nobody [ ;; Δprégnance (tolérance 1) let raw-dprev ([prevalence] of target) - prevalence if raw-dprev < 1 [ set raw-dprev 0 ] let dprev raw-dprev / max-prevalence if dprev > 0 [ ;; distance mémique en valeur absolue des signes let dmem abs(abs(opinion) - abs([opinion] of target)) ;; base-prob + pénalité de polarisation let base-prob dprev * prevalence-weight let pol-penalty max list adoption-floor (1 - polarization-factor * dmem) ;; probabilité brute (sans groupe), pondérée par influence & tx-bonus de l’émetteur let p-adopt base-prob * pol-penalty * [influence] of target * (1 + [tx-bonus] of target) ;; effet de groupe let sgn-emetteur sign ([opinion] of target) let gprob group-alignment-effective self sgn-emetteur let w group-impact-weight let alpha group-impact-alpha set p-adopt p-adopt * ((1 - w) + (w * (gprob ^ alpha))) ;; borne [0,1] if p-adopt < 0 [ set p-adopt 0 ] if p-adopt > 1 [ set p-adopt 1 ] ;; tirage if random-float 1 < p-adopt [ set old-opinion opinion set proposed-opinion [opinion] of target ifelse use-memes? [ ;; renforcement des mèmes du receveur selon le signe de l’émetteur transmit-memes target ;; opinion & prevalence dérivées des mèmes (protégées par metablock) recompute-from-memes ] [ ;; adoption « historique » protégée par veto maybe-set-opinion proposed-opinion ] ;; si veto/reflexion n’a pas modifié le signe et que rien n’a changé → pas de reward if opinion = old-opinion [ stop ] ;; succès de transmission set total total + 1 ;; récompense à l’émetteur si éligible let emitter-sign sign ([opinion] of target) let eligible? (reward-scope = "both") or (reward-scope = "left-only" and emitter-sign < 0) or (reward-scope = "right-only" and emitter-sign >= 0) if eligible? [ ask target [ set tx-bonus min (list reward-cap (tx-bonus + reward-step)) ] ] ;; option : hausse de prégnance du ciblé if reward-prev-delta > 0 [ set prevalence min (list max-prevalence (prevalence + reward-prev-delta)) ] ;; dynamique d’influence (logique existante) set influence-previous influence if vary-influence = true [ if abs(old-opinion) > abs(opinion) [ set influence min (list 1 (influence + rate-infl)) if (influence-previous < 1 and influence = 1) [ if meta-ok = true [ if meta-links < meta-max [ set meta-links meta-links + 1 ] set meta-agents meta-agents + 1 ] set color yellow ] ] if abs(old-opinion) < abs(opinion) [ set influence max (list 0 (influence - rate-infl)) if (influence < influence-previous and influence-previous = 1) [ if meta-ok = true [ set meta-agents meta-agents - 1 ifelse opinion >= 0 [ set color blue ] [ set color red ] ] ] ] ] ;; comptage des inversions (si non bloquée par veto/réflexion) if (sign old-opinion) != (sign opinion) [ set change change + 1 ] ] ] ] ;; modulation de la prévalence if modulation-prevalence = true [ if prevalence > abs opinion * 100 [ set prevalence prevalence - abs(opinion - opinion-previous) * influence * Rate-modulation ] if prevalence < abs opinion * 100 [ set prevalence prevalence + abs(opinion - opinion-previous) * influence * Rate-modulation ] if prevalence < min-prevalence [ set prevalence min-prevalence ] if prevalence > max-prevalence [ set prevalence max-prevalence ] ] ;; bruit additif (protégé par veto/réflexion) if random-float 1 < noise [ let delta (random-float 0.4 - 0.2) maybe-set-opinion (opinion + delta) ] ;; décroissance des mèmes éventuelle if use-memes? [ decay-memes ] ;; update 3D update-3d self ;; logging if (output = "Values" or output = "File") [ compute-statistics ] ] ;; décroissance du bonus (optionnelle) if reward-decay > 0 [ ask turtles [ set tx-bonus max (list 0 (tx-bonus - reward-decay)) ] ] ;; inversion % ifelse (total > 0) [ set inversion (100 * change / total) ] [ set inversion 0 ] end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; COLORATION ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to colorer ask turtles [ ifelse meta? [ set color yellow ] [ ifelse opinion >= 0 [ set color blue ] [ set color red ] ] ] end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; MISE À JOUR DU RÉSEAU (suppression/formation + ponts) ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to update-networks ;; suppression let doomed links with [ abs([opinion] of end1 - [opinion] of end2) > (link-removal-threshold / 100) ] let doomedProb doomed with [ random-float 1 < prob ] let n-remove min (list linksdown count doomedProb) if n-remove > 0 [ ask n-of n-remove doomedProb [ die ] set links-dead links-dead + n-remove ] ;; formation let j linksup while [j > 0] [ let t one-of turtles if t = nobody [ stop ] ask t [ let myop opinion let candidates other turtles with [ not link-neighbor? myself ] let pool-homo candidates with [ abs(opinion - myop) < (link-formation-threshold / 100) ] let pool-bridge candidates with [ (sign opinion) != (sign myop) ] let friend nobody if any? pool-bridge and (random-float 1 < bridge-prob) [ set friend max-one-of pool-bridge [ abs(opinion - myop) ] ] if (friend = nobody) and any? pool-homo [ set friend min-one-of pool-homo [ abs(opinion - myop) ] ] if friend != nobody and (random-float 1 < prob) [ create-link-with friend set links-create links-create + 1 let same-sign? (sign opinion) = (sign [opinion] of friend) ask link-with friend [ set color (ifelse-value same-sign? [ green ] [ gray ]) set thickness linktick if show-links? [ show-link ] ] ] ] set j j - 1 ] end to meta if not network [ stop ] ask turtles [ let pool other turtles with [ color = yellow and not link-neighbor? myself and (count link-neighbors) < meta-links ] if any? pool [ let friend one-of pool create-link-with friend let same-sign? (sign opinion) = (sign [opinion] of friend) ask link-with friend [ set color (ifelse-value same-sign? [ green ] [ gray ]) set thickness linktick if show-links? [ show-link ] ] ] ] end to apply-link-visibility ifelse show-links? [ ask links [ show-link ] ] [ ask links [ hide-link ] ] end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; STATISTIQUES RUNTIME ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to compute-statistics if output = "Values" [ let pre prevalence let mem opinion let infl influence let ag who let ti ticks let ess try let memed (count turtles with [opinion > 0]) / (pop / 100) let maj major output-print (word ess " ; " ti " ; " ag " ; " pre " ; " mem " ; " infl " ; " memed) ] if output = "File" [ let pre prevalence let mem opinion let infl influence let ti ticks output-print (word ti " " pre " " mem " " infl) ] end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; I/O : LECTURE FICHIER D’AGENTS ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to in_file carefully [ set file-in user-file if (file-in != false) [ set list_data [] file-open file-in while [not file-at-end?] [ set list_data sentence list_data (list (list file-read file-read file-read file-read)) ] file-close user-message "File uploaded!" set in_data true ] ] [ user-message "File read error" ] data end to data clear-turtles clear-links let tick_to_load choice_iter ifelse (is-list? list_data) [ let filtered_data filter [ row -> first row = tick_to_load ] list_data create-turtles length filtered_data [ let my_index who let agent_data item my_index filtered_data set prevalence item 1 agent_data set opinion item 2 agent_data set influence item 3 agent_data if influence = 1 [ set meta-agents meta-agents + influence ] set opinion-previous opinion set influence-previous influence set tx-bonus 0 if opinion < 0 [ set color red set agent-type "Left side" ] if opinion > 0 [ set color blue set agent-type "Right side" ] if influence = 1 [ set color yellow ] ;; init mèmes en cohérence let tot initial-prevalence-to-memes prevalence ifelse opinion >= 0 [ set meme-plus tot * (0.5 + 0.5 * abs opinion) set meme-minus tot - meme-plus ] [ set meme-minus tot * (0.5 + 0.5 * abs opinion) set meme-plus tot - meme-minus ] update-3d self ] ] [ set in_data false user-message "Read error" ] update-networks apply-link-visibility recolor-links influenceurs update-opinions set repet_data true end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; ÉVÉNEMENT EXTERNE (protégé par veto/réflexion) ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to event ask turtles [ ifelse meme_set = true [ if (to_left = false) [ if agent-type = "Right side" [ if opinion < 0 [ maybe-set-opinion (opinion + event_size) ] ] ] if (to_left = true) [ if agent-type = "Left side" [ if opinion > 0 [ maybe-set-opinion (opinion - event_size) ] ] ] ] [ if (to_left = false) [ if (opinion < high_meme and opinion > low_meme and prevalence < high-prev and prevalence > low-prev) [ maybe-set-opinion (opinion + event_size) if (prev_change != 0) [ set prevalence min (list max-prevalence (prevalence + prev_change)) ] ] ] if (to_left = true) [ if (opinion > low_meme and opinion < high_meme and prevalence > low-prev and prevalence < high-prev) [ maybe-set-opinion (opinion - event_size) if (prev_change != 0) [ set prevalence min (list max-prevalence (prevalence + prev_change)) ] ] ] ] ] end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; UTILITAIRES ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to set-background-black ask patches [ set pcolor black ] end to update-3d [agt] ask agt [ set x3d opinion * 16 set y3d prevalence / 6 set z3d influence * 16 setxyz x3d y3d z3d ] end to-report safe-median [agentset varname] if not any? agentset [ report 0 ] report median [ runresult varname ] of agentset end to-report sign [x] ifelse x > 0 [ report 1 ] [ ifelse x < 0 [ report -1 ] [ report 0 ] ] end to recolor-links ask links [ let s1 sign [opinion] of end1 let s2 sign [opinion] of end2 ifelse s1 = s2 [ set color green ] [ set color gray ] set thickness linktick ] end ;; IMPACT DE GROUPE (tous les voisins liés) to-report group-alignment-all [agt sign-ref] let nbrs [link-neighbors] of agt if not any? nbrs [ report 0.5 ] let same count nbrs with [ (sign opinion) = sign-ref ] report same / count nbrs end ;; IMPACT DE GROUPE (k plus proches) to-report group-alignment-k [agt sign-ref k] let nbrs [link-neighbors] of agt let deg count nbrs if deg = 0 [ report 0.5 ] let kk max list 1 min list deg floor k let agop [opinion] of agt let pool min-n-of kk nbrs [ abs(opinion - agop) ] if not any? pool [ report 0.5 ] let same count pool with [ (sign opinion) = sign-ref ] report same / count pool end ;; Sélecteur de mode to-report group-alignment-effective [agt sign-ref] ifelse (group-impact-mode = "k-nearest") [ report group-alignment-k agt sign-ref group-k ] [ report group-alignment-all agt sign-ref ] end ;; Mapping prevalence -> stock initial de mèmes to-report initial-prevalence-to-memes [prev] report (prev / 99) * meme-max end ;; Recalcule opinion & prevalence à partir des mèmes (protégé par veto/réflexion) to recompute-from-memes let tot meme-plus + meme-minus if tot < 1e-6 [ set tot 1e-6 ] set proposed-opinion ((meme-plus - meme-minus) / tot) maybe-set-opinion proposed-opinion let scaled (tot / meme-max) * 99 if scaled < 0 [ set scaled 0 ] if scaled > 99 [ set scaled 99 ] set prevalence scaled end ;; Décroissance des mèmes to decay-memes if meme-decay <= 0 [ stop ] set meme-plus max list 0 (meme-plus * (1 - meme-decay)) set meme-minus max list 0 (meme-minus * (1 - meme-decay)) end ;; Transmission des mèmes d’un émetteur vers le receveur (self) to transmit-memes [emitter] let sgn sign [opinion] of emitter ifelse sgn >= 0 [ set meme-plus meme-plus + meme-gain set meme-minus max list 0 (meme-minus - meme-anti-leak * meme-gain) ] [ set meme-minus meme-minus + meme-gain set meme-plus max list 0 (meme-plus - meme-anti-leak * meme-gain) ] ;; plafonner en douceur let tot meme-plus + meme-minus if tot > meme-max [ let factor meme-max / tot set meme-plus meme-plus * factor set meme-minus meme-minus * factor ] end ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; ;; EXPORT CSV (par essai) ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;; to csv-begin if not csv-export [ stop ] set csv-file (word csv-basename "-" try ".csv") file-close-all if file-exists? csv-file [ file-delete csv-file ] file-open csv-file set csv-open? true file-print "try,iter,tick,left_pct,right_pct,avg_opinion,med_op_right,med_op_left,med_prev_right,med_prev_left,med_infl_right,med_infl_left,links_remove,links_create,inversion_pct,change,total,fractale,major" end to csv-row if not csv-open? [ stop ] let avg-opinion mean [opinion] of turtles let opR safe-median (turtles with [opinion >= 0]) "opinion" let opL safe-median (turtles with [opinion < 0]) "opinion" let prevR (safe-median (turtles with [opinion >= 0]) "prevalence") / 100 let prevL (safe-median (turtles with [opinion < 0]) "prevalence") / 100 let inflR safe-median (turtles with [opinion >= 0]) "influence" let inflL safe-median (turtles with [opinion < 0]) "influence" let leftpct (count turtles with [opinion < 0]) / (pop / 100) let rightpct (count turtles with [opinion >= 0]) / (pop / 100) file-print (word try "," iter "," ticks "," leftpct "," rightpct "," avg-opinion "," opR "," opL "," prevR "," prevL "," inflR "," inflL "," links-dead "," links-create "," inversion "," change "," total "," fractale "," major) end to csv-end if csv-open? [ file-close set csv-open? false ] end
There is only one version of this model, created 10 days ago by Pierre-Alain Cotnoir.
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