Stumbleupon Review of : http://www.unm.edu/~psych/faculty/articles/greengross humor 2008.pdf
From the PDF: "Dissing Oneself versus Dissing Rivals: Effects of Status, Personality, and Sex on the Short-Term and Long-Term Attractiveness of Self-Deprecating and Other-Deprecating Humor"
Thank goodness I lack the wit to engage in self-deprecating humour is all I can say.