Evolution of human cooperation without reciprocity Balaraju Battu Centre of Behavioural and Cognitive Sciences (CBCS) University of Allahabad, Allahabad 18th March 2016

What is cooperation In a cooperative action Donor pays cost, c, and recipient gets benefit, b Costs and benefits are measured in terms of fitness reproduction can be genetic or cultural

Long standing problem in biological and social sciences is to understand conditions required for the emergence and maintenance of cooperation in evolving populations. The following mechanisms are proposed Kin selection : Recognition of kin Direct reciprocity: repeated interactions, memory of past actions Indirect reciprocity: Ability to judge actions (good or bad) and communicate (language ability) Spatial selection: Group selection:

Evolutionary dynamics Population (reproductive individuals) Mutation (errors in reproduction) Selection (selecting fitter types relative to others) Evolutionary game theory

Cooperation without reciprocity Population type : Heterogeneous individuals, i.e. have different capacity to imitate others’ actions in the population. Donor and receivers pairs are randomly picked form population. Each individual interact with each other individual only once. i.e. No two individuals interact more than once. After each generation Individuals are updated to the next generation by synchronously and 10% population under goes mutations.

Results and discussions The donation rates depend on population size, ability to copy, benefit and cost values. Our results extends previous literature cooperation based on image scoring and tag based cooperation. The mechanism does not required repeated interactions, therefore memory of past interactions is required, does not required one agent observe and recall/judge actions of others and communicate to others, and does not require to reorganization tags. Individuals with ability to use social information and ability to copy successful actions of others, the population might maintain cooperation.

Thank you (for cooperation)