I'm looking for references to studies that show which variables increase or decrease self-awareness and to what degree.
For example, internal variables could be level of a certain vitamin, brain chemical, oxygen level, form of spine, etc. and/or external variables like emotional trauma, meditation, altitude, contact with water, etc.
This is just a sketch of an answer. It is important to clarify how we define "self-awareness".
The self: There is a huge social psychological literature on the self. For a scientific review, see for example Ellemers et al (2002). Even the concept of self-awareness is contentious in that it posits that there is a self to be discovered whereas I assume most researchers would acknowledge that the self is at least partially a social construction.
Psychological well-being: A sense of self-awareness also relates to many other constructs such as having a sense of life purpose or meaning. For more information on that you could look at the psychological well-being literature. At the risk of self-promotion, I can point you to Grant et al (2009) where we reported some of Big 5 correlates of psychological well-being where for example we showed that self-reported purpose in life (i.e., a little bit like self-awareness) correlated well with high extraversion (r=.33), high conscientiousness (r=.45) and low neuroticism (r = -.44).
Self-efficacy: An alternative perspective would be to look at self-efficacy research. Such research often looks at the relationship between a person's predicted and actual performance. Such research often shows that specific performance feedback with practice is important in generating accurate self-beliefs about one's own competence.
Self-other correlations: I imagine also that there is literature that looks at self-other correlations for various characteristics. It would be interesting to see what predicts the size of self-other discrepancies in such domains as personality, and performance. Unfortunately, I don't have any particular references on hand.
