The irony of heuristics and motivation.
The central irony in the book is the irony of misunderstood motivation. If you test a group of people, most of the time, people will self report that their experience of life is largely analytical, and that they believe things for specific, defensible reasons. But if you test those theories individually, pretty soon it becomes clear that human motivation is an illusion. Ironically, even the minutia can be scientifically proven to matter in terms of human motivation, things as subtle as "What number was the last number you saw with your eyes," can be as influential in decision-making as any number of more obvious motivators.
The irony of behavior.
This irony is closely related to the common literary issue of free will. Do we have free, independent consciousnesses? Or is our behavior secretly linked to a myriad of manipulable factors? The studies show overwhelmingly that our behavior is linked to our environment, meaning that we feel like we're making choices, but really, we're being constantly influenced in our decision-making. People are not independent agents for behavior, but rather, a sensitive psychological entity with irrational principles.
The irony of rationalism.
Although rationality has been a virtue in Western cultures for a long time, it hasn't been until recently that scientists have shown demonstrably that our own mind can be deconstructed. This is one of the first economic applications of that basic irony, that people feel in control, but they're basically not.
The irony of influence.
Think about changing someone's mind. Typically, combative imagery comes to mind, launching attacks, having clever, insightful defenses for one's ideas, being willing to stand up for one's self, etc. However, in reality, almost anyone can be brainwashed into believing any number of things, just by exploiting various cognitive tricks.
The brain is hardwired in a way that leaves blind spots, openings for new data to reconstruct our opinions, and through scientific inquiry, marketing agencies have already been exploiting these openings, basically since Tversky and Kahneman.
The irony of group psychology.
There are a lot of ironies related to group identity and group psychology. The most important irony is that by associating oneself to a group, one statistically improves the likelihood that they'll believe something more extreme. This is called group think, and it's among the ideas explored by Tversky and Kahneman in their deconstruction of behavior.
Another irony is that even though our beliefs feel independent, a lot of our core beliefs were taught to us by a group, meaning that the group has power over us that we don't detect. This is a basic marketing tool and has led to the marketing strategies of band-wagoning and insider/outsider divides.
