Oops! Reviewing my code... I see that I had the logic backwards. The probability that keeps spiking is actually that of an unwarranted cooperation! Here is a plot with the total numbers of defect-defect, defect-cooperate, and cooperate-cooperate rounds of the game. There are 100 strategies, so that is 4950 pairs, and each pair is run for 100 iterations. Thus the total across all three categories should be 495, 000. Whew! Looks like a match!
After receiving a Master's degree in physics in 1981, I worked in the semiconductor industry, developing software that engineers used to check and optimize designs of digital circuits.
Having practiced Buddhism since 1980, I completed a traditional three year meditation retreat at Karme Ling Retreat Center, New York, in 1996.