This is an interesting radio show on choice, priming and free will. It's about an hour long but has some really neat stuff on psychological experiments and whatnot that have been conducted in this area. I've summarized some key points below, in case you do not have time/feel like lisening to the show.
WNYC - Radiolab: Choice (November 14, 2008)
In the radio show Schwartz talked about how having too many opportunities can be overwhelming. He described this as choice angst. He talked about the magic number seven, plus or minus two. This means that the mind can only hold roughly seven items in it at one time, and this can result in screwing up reason. They gave support for this in a study where they had people memorize either two or seven numbers. The people who were in the process of memorizing two numbers, when asked if they wanted a bowl of fruit or a piece of chocolate cake, chose fruit over cake more often than those people in the process of memorizing seven numbers. This indicates that memorizing seven numbers preoccupied their reasoning skills so it was more difficult for them to choose the practical thing, that is, the bowl of fruit. Since I know that I would choose the chocolate cake in any situation, I wonder what this says about my reasoning skills? Perhaps this is what it means to have dominate Ni and barely any Ti (my case)?
The radio show also discusses how emotions play an important role in decision making. They describe a gut feeling as a short hand average of past wisdom. So, when standing in a cereal aisle, it doesnít take a whole day to pick a cereal because your gut feeling will tell you that you want Crackliní Oat Brans because your past experiences with that cereal were overall good. This allows you to make a snap decision, "I want this cereal!" without really knowing why. Another study was concuted where free posters were given out, either an impressionistic poster or a poster of a cat hanging ("Hang in There"). One condition of the experiment was that the people had to explain why they chose what they did, and in the other condition they did not need to make an explaination. What they found was that people who had to explain their choice more often chose the cat picture, and also ended up disliking their picture more six months after the experiment. They didnít go into great detail as to why this was, but it could have something to do with the fact that they made people rationalize a choice that is usually made on gut reaction. Because they had to rationalize it, they chose poorly because they were falling ill to the magic number seven effect, where they were trying to rationally compare too many things in their head about the posters so they ended up making the wrong choice. I.e., this one is bigger but this one is prettier but this one is cuter but this one is funnier but this one....