According to this article (http://www.physorg.com/news158928941.html) quantum theory
may explain some cases of “wishful thinking”.

(PhysOrg.com) — Humans don’t always make the most rational decisions. As studies have shown, even when logic and reasoning point in one direction, sometimes we chose the opposite route, motivated by personal bias or simply “wishful thinking.” This paradoxical human behavior has resisted explanation by classical decision theory for over a decade. But now, scientists have shown that a quantum probability model can provide a simple  explanation for human decision-making – and may eventually help explain the success of human cognition overall.

In one study, participants were told that they
had just played this game, and then were asked to choose whether to try the same gamble
again. One-third of the participants were told that they had won the first game, one-third
were told they had lost the first game, and the remaining one-third did not know the outcome of their first game. Most of the participants in the first two scenarios chose to play
again (69% and 59%, respectively), while most of the participants in the third scenario
chose not to (only 36% played again). These results violate the “sure thing principle,” which
says that if you prefer choice A in two complementary known states (e.g., known winning
and known losing), then you should also prefer choice A when the state is unknown. So why

do people choose differently when confronted with an unknown state?

“In their study, the scientists compared two models, one based on Markovian classical probability
theory and the other based on quantum probability theory. They modeled a game based on
the Prisoner’s Dilemma, which is similar to the gambling game. Here, participants were asked if they wanted to cooperate with or defect from an imaginary partner. Overall, each partner would receive larger pay-outs if they defected, making defecting the rational choice. However, if both partners cooperated, they would each receive a higher pay-out than if both defected. Similar to the results from the gambling games, studies have shown that participants who were told that their partner had defected or cooperated on the first round usually chose to defect on the second round (84% and 66%, respectively). But participants who did not know their partner’s previous decision were more likely to cooperate than the others (only 55% defected). It seems as if these individuals were trying to give their partners the benefit of the doubt, at the expense of making the rational choice.”

I personally, think it should be called “benefit of the doubt thinking” rather than wishful thinking. The article describes how in the “unknown” the other side is viewed as a mirror of themselves. Read the article for a better, deeper explanation. It’s worth the read if you are interested in that sort of thing.