The choice of reasons we offer and accept for our beliefs and actions is without a doubt also a question of convention. Conventions concerning 'valid' or 'interesting' arguments and ways of justifying beliefs are at least partially dependent upon styles or tastes.What we consider to constitute acceptable justifications depend upon conventions.
For example, how do we reason about the 'quality' or legitimacy of academics? Previously, the judgments would have been based on the reading of key works, scholar affiliation, and various other sources of reputation. Today, increasingly the reasoning concerning academics is driven by numeric indices -- citation counts, numbers of A-publications, etc. The taste for quantified reasoning has spread and penetrated most areas of life now.
Unfortunately, humans seem to have a natural taste for the unconditional. This is what I mean. If possible, the private inferences and public arguments are grounded on beliefs and values that are absolute and unconditional. Such behavior is most emphasized in moral reasoning, where (quite naturally) we want to base our behavior on unconditional principles (e.g. the golden rule). Reasoning based on unconditional principles constitutes essentially fundamentalism. Beyond moral fundamentalism (which is not always disasterous) the love for the unconditional is evident in substantive areas, including 'market fundamentalism'. Holding the principles of free markets as unconditional guidelines for reasoning about choices and actions is enticing but inevitably leads to 'unreasonable' prescriptions.
The phrase 'taste for the unconditional' comes from Nietzsche (in Beyond Good and Evil), where it is mentioned in passing. For Nietzsche the tendency (of youth, in his mind) to rely on unconditional premises in reasoning about one's opinions and beliefs is not merely a bad taste, but 'the worst of all tastes'. Are managers victims of this bad taste? Or might such bad taste is in fact beneficial in politics and business? It certainly seems that many management gurus embrace and catalyze such bad taste by emphasizing the need of managers to 'focus on core competencies' (Hamel & Prahalad) or orient the decision making in their corporations around simple 'rules of thumb' (Eisenhardt & Martin).
Finally, some styles of reasoning are specifically related to social settings. In addition to monologies we have dialectical and dialogical ways of reasoning. The Blogger statistics suggest that there are dozens of page hits, but there are yet no comments on any of the blog texts. My reasoning would obviously be greatly enhanced by the introduction of more dialogue.