Unrelated individuals cooperate when mutual help raises both survival odds

Evidence

Two cooperating individuals are not necessarily related, but they are both more likely to survive and reproduce themselves if they help each other. This category includes examples of types like the iterated Prisoner’s Dilemma, dealt with so interestingly by Axelrod (1984). For a specified set of pay-offs, everybody benefits by cooperating at the outset. — Diego Gambetta, Trust - Making and Breaking Cooperative…, 371

Two cooperating individuals are not necessarily related, but they are both more likely to survive and reproduce themselves if they help each other. This category includes examples of types like the iterated Prisoner’s Dilemma, dealt with so interestingly by Axelrod (1984). For a specified set of pay-offs, everybody benefits by cooperating at the outset. I shall focus here on joint parental care of the offspring. — Diego Gambetta, Trust - Making and Breaking Cooperative…, 371

Categorization

• DEFINE: Defines ‘mutualism within a species’ as cooperation between unrelated individuals where both benefit.
• XREF: Iterated Prisoner’s Dilemma and Axelrod’s cooperator-robustness map onto Milgrom’s repeated-trade equilibria in the reader’s institutional economics material — same formal structure of cooperation under repeated interaction. — connects to: Shared fate in danger makes strangers act as one group offering help. — John Drury, The role of social identity processes…, 47; Mutual helping, not selfish flight, is the dominant emergency behaviour — John Drury, The role of social identity processes…, 31; Effective prevention requires coordinated interventions across multiple social levels — Ryan Andrew Brown, Todd C. Helmus, Rajeev Ramchand, Alina I. Palimaru, Sarah Weilant, Ashley L. Rhoades, and Liisa Hiatt (RAND Corporation), Violent Extremism in America:…, 116
• corroborated: 2 independent passages support this claim — Diego Gambetta, Trust - Making and Breaking Cooperative…, 371