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Equation 11 · Part 1 · Why We Punish Strangers: The Evolution of Human Cooperation

Symbol y

yy
yy

What this part means

y is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

Its job in the formula

y is a part of this expression. Its role is fixed by the surrounding article and by the operations shown in the formula.

The passage around this formula

…the punisher’s fitness disadvantage relative to a non-punishing cooperator shrinks toward zero even while the plain cooperator’s disadvantage relative to a defector does not. Writing x for the frequency of cooperators, y for the frequency of punishers, and k for the cost of punishing a single defector, the punisher’s expected fitness penalty is approximately

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Sources cited in the surrounding passage

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