In response to #4, Objectivism does not disregard emotion; rather, it puts it into a logical construct. Although emotions are not tools of cognition, emotions, when understood, can lead to deeper self-awareness, of why we do what we do, of understanding one's own causes and effects. Asking the question of "Why I feel the way I do" can only lead to a rational self-understanding. One's actions and reactions may be automatic, or "based on emotion," or rational or irrational, but an individual's comprehension of their own emotional state can only further them in their rational being.
This is an enormous topic. When I did a search of it in Google Books, I turned up a huge number of relevant books. Here's what I found:
When faced with a topic this large, it's often useful to find an annotated bibliography -- that is, a listing of relevant materials that briefly discribes each publication.
Here's what I found when I searched for an annotated bibliography. Notice that you will need to scroll through the findings to find material that is precisely relevant:
You may also want to look here:
Whilst I agree that we are less reasonable individuals than we would like to give ourselves credit for, at the same time I think that reason is still an important factor that enters the complex amalgam of the decision-making process. Often we finally make a decision based more on our emotions than anything else, but at the same time the importance of reason should not be ignored.
I agree with the poster who stated that 'reason' is not a factor in every human decision that is made throughout the day. There are some instances where our natural instincts take over, and we make immediate decisions without much time to reason. The 'flight or fight' response is an example of instinctive type of decision making. As for the many times 'reason' plays a factor in the decision-making process, it's role will vary depending on the situation and the individual. Sometimes we really don't take the time to reason or justify our actions. Many times these actions, such as drinking too much at a party for example, are based on our wants and desires of the moment.
Not all human actions are the result of a reasoned decision-making process. Many times, actions are impulsive and/or emotional in nature. We have to be socialized and educated to control our behavior and actions in more reasoned ways. That being said, reasoning is inherently beneficial to the individual, as you are evaluating the pros and cons of any action, and the possible benefits and consequences, so there is also a natural motivation to use reason.
I think that people's ability to reason is as different as people themselves. One cannot blanket reason as a global thing. Given any one situation, any number of people will have multiple reasons (and reasoning processes) to arrive at a specific answer.
I agree with the other posters that too many things influence any given situation. There are simply too many variables. Emotions do play a role in making decisions. Sometimes, emotions will tend to over-ride pure reason.
I don't know if most people use much pure reason at all in their daily lives. I'd have to see if there were any studies, but my gut feeling (see?) is that most people base decisions on emotion. Consider the reason-based philosophy, Objectivism. One of its basic principles is that knowledge can only be based on fact, not assumption or opinion; everything must be derived from empirical facts. However, in each person's subjective life, there must be room for decisions based on gut feelings and emotion, even if your personal philosophy rejects the sanity of those decisions. The result is a fractured following who disagree on virtually every part of the philosophy itself.
Objectivism rejects both faith and "feeling" as sources of knowledge. Rand acknowledged the importance of emotion for human beings, but she maintained that... "Emotions are not tools of cognition."
I agree with the previous post - there really can't be one all-inclusive response to this question. Too many variables impact any decision that needs to be made. Sometimes those variables can be addressed with reasoning and rational analysis; sometimes actions and decisions need to be based on other factors. Actually, I would guess that most of the time combination of reason and emotion is involved in making plans for action!
The answer to this will vary between people and in different situations. It is also very hard to know the answer for certain because we can not always be sure of how we come to decide what we will do.
In general, reason will play a much lesser role in personal interactions than it will in things like our economic choices. We will not typically choose our friends in rational ways, for example. We will be much more likely to decide something like which TV or car to buy based on reason. Of course, there may well be some ways in which reason enters into our choice of friends or emotion enters into our choice of TV or car. However, I would generally argue that reason plays a large role in determining our actions in things like our buying decisions and our actions at our jobs.