[dTal]

Here's one - attractiveness is roughly correlated with intelligence, and in the general case positive traits tend to correlate. An interview is an attempt to extract the maximum amount of information about a candidate in a short space of time. Virtually any positive trait is evidence that somebody will be a better candidate. Weak evidence, yes - but if you have two otherwise completely identical candidates (a silly hypothetical) it's not illogical to choose the one with better hair follicles (a silly outcome of a silly hypothetical).