The paper explores the disjunction effect in the Prisoners dilemma game using behavioral experiments with eye-movement recordings. An experiment was designed to explore the complexity hypothesis about the appearance of the disjunction effect. The results show that in games with payoffs which are simpler to perceive and compare, the disjunction effect disappears, while it is present when more complex payoffs are used. In a second experiment, the participants were told that the moves of the computer opponent had been made before the game session. This manipulation led again to the disappearance of the disjunction effect even. We interpret this result as a suppressing of a possible quasi-magic reasoning by stressing the fact that participants own moves cannot influence the move of the opponent. The results from the experiments point to information processing complexity as a major factor for the disjunction effect contrary to the conclusions in some previous research.