In strategic form theory, a collective action game is one where certain strategy profiles promote the collective interest of the players using spontaneous or coercive collaboration.
Conversely, a zero sum game is one whose strategies do not have a collective action differential, and the sum of the payoffs of each strategy profile amounts to 0.
Examples
Stag Hunt
The stag hunt game has a clear collective action component. Consider the following game matrix:
\begin{document}\begin{tikzpicture} % Draw the vertical lines \draw (0, 0) -- (0, -3); \draw (1.5, 0) -- (1.5, -3); \draw (3, 0) -- (3, -3); % Draw the horizontal lines \draw (0, 0) -- (3, 0); \draw (0, -1.5) -- (3, -1.5); \draw (0, -3) -- (3, -3); % Add labels for players \node at (1.5, 1) {Survivor 2}; \node[rotate=90] at (-1, -1.5) {Survivor 1}; % Add labels for Player 2's choices \node at (0.75, 0.25) {S}; \node at (2.25, 0.25) {H}; % Add labels for Player 1's choices \node at (-0.25, -0.75) {S}; \node at (-0.25, -2.25) {H}; % Add payoffs for each cell \node at (0.75, -0.75) {(3, 3)}; \node at (2.25, -0.75) {(0, 1)}; \node at (0.75, -2.25) {(1, 0)}; \node at (2.25, -2.25) {(1, 1)};\end{tikzpicture}\end{document}
Here, only when both survivors decide to catch a stag do they successfully do so, each receiving a utility of 3.
The stag hunt game has a clear collective action component in (S,S). The players are much better off choosing to hunt a stag together than going their separate ways or hunting a hare together.
Rock, Paper, Scissors
Rock, paper, scissors is an example of a game that is zero sum. Consider the following game matrix:
\begin{document}\begin{tikzpicture} % Draw the vertical lines \draw (0, 0) -- (0, -4.5); \draw (1.5, 0) -- (1.5, -4.5); \draw (3, 0) -- (3, -4.5); \draw (4.5, 0) -- (4.5, -4.5); % Draw the horizontal lines \draw (0, 0) -- (4.5, 0); \draw (0, -1.5) -- (4.5, -1.5); \draw (0, -3) -- (4.5, -3); \draw (0, -4.5) -- (4.5, -4.5); % Add labels for players \node at (2.25, 1) {Player 2}; \node[rotate=90] at (-1, -2.25) {Player 1}; % Add labels for Player 2's choices \node at (0.75, 0.25) {Rock}; \node at (2.25, 0.25) {Paper}; \node at (3.75, 0.25) {Scissors}; % Add labels for Player 1's choices \node[rotate=90] at (-0.25, -0.75) {Rock}; \node[rotate=90] at (-0.25, -2.25) {Paper}; \node[rotate=90] at (-0.25, -3.75) {Scissors}; % Add payoffs for each cell \node at (0.75, -0.75) {(0, 0)}; \node at (2.25, -0.75) {(-1, 1)}; \node at (3.75, -0.75) {(1, -1)}; \node at (0.75, -2.25) {(1, -1)}; \node at (2.25, -2.25) {(0, 0)}; \node at (3.75, -2.25) {(-1, 1)}; \node at (0.75, -3.75) {(-1, 1)}; \node at (2.25, -3.75) {(1, -1)}; \node at (3.75, -3.75) {(0, 0)};\end{tikzpicture}\end{document}
There is clearly no collective action component in this game, since when one player wins, the other loses an equivalent amount of utility.