EvoLudoLab: Spatial 2x2 Game - Dominance A

Color code:	Cooperators	Defectors
	New cooperator	New defector

Payoffs:	Low High

Note: The gradient of the payoff scale is augmented by pale shades of the strategy colours to mark payoffs that are achieved in homogeneous populations of the corresponding type.

Type A dominates

In well-mixed populations type \(A\) players dominate and take over the population irrespective of the initial configuration. Essentially the same happens in spatially structured populations.

In the case of by-product mutualism, the success of cooperation hinges on the presence of a sufficiently big cluster of cooperators. The required cluster size is small (often two adjacent cooperators are enough but depends on the payoffs and stochasticity of the update rules). It is also interesting to observe the difficulties in eliminating all defectors - increasing the stochasticity such that players occasionally switch to worse performing strategies would speed up that process.

The parameters above are set to \(R = 1, P = 0, T = 0.9\) and \(S = 0.1\) with players imitating better strategies proportional to the payoff difference on a 100×100 lattice with only 0.5% cooperators initially. With some small probability cooperators will go extinct. To reduce this risk, you can either increase the system size or the initial fraction of cooperators.

Data views

Strategies - Structure	Snapshot of the spatial arrangement of strategies.
Strategies - Mean	Time evolution of the strategy frequencies.
Fitness - Structure	Snapshot of the spatial distribution of payoffs.
Fitness - Mean	Time evolution of average population payoff bounded by the minimum and maximum individual payoff.
Fitness - Histogram	Snapshot of payoff distribution in population.
Structure - Degree	Degree distribution in structured populations.
Statistics - Fixation probability	Statistics of fixation probabilities.
Statistics - Fixation time	Statistics of fixation and absorption times.
Console log	Message log from engine.

Game parameters

The list below describes only the few parameters related to the Prisoner's Dilemma, Snowdrift and Hawk-Dove games. Follow the link for a complete list and detailed descriptions of the user interface and further parameters such as spatial arrangements or update rules on the player and population level.

--paymatrix <a00,a01;a10,a11>

2x2 payoff matrix. Type \(A\) has index 0 and type \(B\) index 1.

--reward <a11>

the reward for mutual cooperation. The payoff of type \(A\) against its own type (see --paymatrix).

--temptation <a10>

the temptation to defect. The payoff of type \(B\) against type \(A\) (see --paymatrix).

--sucker <a01>

the sucker's payoff of an exploited cooperator. The payoff of type \(A\) against type \(B\) (see --paymatrix).

--punishment <a00>

the punishment for mutual defection. The payoff of type \(B\) against its own type (see --paymatrix).

--init <a,b>

initial frequencies of type \(A\) and \(B\), respectively. Frequencies that do not add up to 100% are scaled accordingly.

--inittype <type>

type of initial configuration:

frequency

random distribution with given frequency

uniform

uniform random distribution

monomorphic

monomorphic initialization

mutant

single mutant in homogeneous population of another type. Mutant and resident types are determined by the types with the lowest and highest frequency, respectively (see option --init).

stripes

stripes of traits

kaleidoscopes

(optional) configurations that produce evolutionary kaleidoscopes for deterministic updates (players and population). Not available for all types of games.