  Emergence of cooperation in self-centered individuals has been a major puzzle
in the study of evolutionary ethics. Reciprocal altruism is one of explanations
put forward and prisoner's dilemma has been a paradigm in this context.
Emergence of cooperation was demonstrated for prisoner's dilemma on a lattice
with synchronous update [Nature, 359, 826 (1992)]. However, the cooperation
disappeared for asynchronous update and the general validity of the conclusions
was questioned [PNAS, 90, 7716 (1993)]. Neither synchronous nor asynchronous
updates are realistic for natural systems. In this paper, we make a detailed
study of more realistic system of semi-synchronous updates where pN agents are
updated at every time instant. We observe a transition from all-defector state
to a mixed state as a function of p. Despite being transition from absorbing
state, our studies indicate that it is a first order transition. Furthermore,
we used damage spreading technique to demonstrate that, the transition in this
system could be classified as a frozen-chaotic transition.
