  We consider a spatial model of the emergence of cooperation with synchronous
births and deaths. Agents bear a tag and interact with their neighbors by
playing the prisoner's dilemma game with strategies depending on their own and
opponent's tags. An agent's payoff determines its chances of reproducing and
passing on its strategy. We show that when tags are assigned at random rather
than inherited, a significant heterophilic population of about 40~\% of the
whole can emerge and persist. Heterophilics defect on agents bearing the same
tag as theirs and cooperate with others. In our setting, the emergence of
heterophily is explained by the correlation between an agent's payoff and its
neighbors' payoffs. The advantage of heterophily over homophily (cooperating
with agents bearing one's tag and defecting with others) when tags are assigned
at random makes the emergence of the later an even more interesting phenomenon
than previously thought.
