It is also the case that not everyone has the biological machinery to make decisions at a very high level of thought or reasoning.
What do you mean by this? You seem to imply that there are structural diffrences inherent in human brains that make some people capable of "a very high level of thought and reasoning" and some people incapable. That seems unlikely or even impossible: see The Psychological Unity of Humankind.
I do agree with you that some people do sometimes make decisions at a high level of thought and reasoning, and some people rarely or never do. Unless we're talking about actual mental retardation, I think the differences would have to be mostly based on education and culture.
Only someone who hasn't spent much time around people with 2-digit IQ's would believe in "the psychological unity of humankind." The empirical evidence shows that at least in the area of IQ or the General Intelligence Factor (g), marginal differences can have profound practical consequences:
Why g Matters: The Complexity of Everyday Life
http://www.udel.edu/educ/gottfredson/reprints/1997whygmatters.pdf
Nick Bostrom in one of his talks even argues that raising everyone's IQ by 10 points would revolutionize our society for the better, not by ma...
From Mike Darwn's Chronopause, an essay titled "Would You Like Another Plate of This?", discussing people's attitudes to life:
Conclusion, graphs, and references in article. As usual, I recommend reading Chronopause.com as Darwin has many good articles; to quickly link a few: