Online Altruism Lab

Introduction

... and welcome to the Online Altruism Lab!

Altruism – A Darwinian Puzzle

However, there are countless examples of this in nature. Classic examples are the warning calls in birds, sterile worker castes in social insects, and food sharing among primates. Recent research is uncovering more and more altruistic traits also in microbes, bacteria, fungi, and other organisms (Cremer et. al., 2019).

In each case, the individual performing the altruistic act reduces its own fitness — in extreme cases even to the point of self-sacrifice — while simultaneously promoting the survival or reproductive success of others. Explaining how such altruistic traits evolve has become a central theme in evolutionary biology.

Proposed solutions

Several mechanisms have been proposed for solving the altruism puzzle and the evolution of cooperation, but there is no consensus on their validity. Nowak (Nowak, 2012) distinguishes between the following five mechanisms.

The most widespread approach in biology is kin selection, which relies on the genetic relationship of the cooperating actors (Hamilton, 1964). The main beneficiary of the cooperation is not the individual, but the common "gene" that the relatives share. An individual can therefore even sacrifice its life if this saves enough relatives to make it worthwhile for the shared gene. Only the "inclusive fitness" must show a positive balance.

A different and often seen opposite concept is group selection. The basic idea goes back to Darwin’s assumption that groups compete with each other (Darwin, 1888). This means that groups of individuals, rather than individuals, are the units on which selection acts. A modern version of this, multilevel selection, assumes that selection acts at different levels, such as both the individual and the group level (Sober and Wilson, 1998; Wilson and Wilson, 2008).

Two further solution mechanisms for the altruism puzzle are direct and indirect reciprocity. In the case of direct reciprocity (Trivers, 1971), the costs and benefits of repeated interactions between the actors are extrapolated and analyzed using game theory. In the case of indirect reciprocity, the alleged altruism is rewarded with reputation, which later benefits the actor. Both approaches attempt to eliminate the negative fitness balance of apparent altruism and show that it is in fact not an altruistic trait after all, but serves one's own advantage.

The fifth mechanism for the evolution of cooperation is spatial selection (Nowak, 2012). This is based on the fact that not every individual can interact with every other individual, but that the population is spatially structured and interactions only take place in a limited environment.

Spacial selection and structured populations

In a well-mixed population (everyone interacts randomly with everyone else), altruistic behaviors are usually selected against, because defectors (egoists) exploit cooperators (altruists) and gain higher payoffs. But in a structured population, where interactions are localized (e.g., within groups, on a lattice, in spatial neighborhoods, or in social networks), the dynamics can change dramatically.

Since our human minds struggle to understand complex dynamics, the computers should do the hard work for us. For this purpose, I have created the various simulation models presented on this website, all of which can lead to stable altruism based solely on structured populations.

All simulation models were created by me in Netlogo (Wilensky, 1999) and should run in all common browsers. Please contact me if you encounter any problems or errors.