Actually, this 'experiment' was a setup.
Social and experimental psychologists had determined decades ago that there is a correlation between facial features and presumed character traits.
The facial features in that idealized photo of hillary (e.g., wideset blue eyes, (surgery-assisted) absence of a frown) is consistent with positive presumed character traits. Conversely, McCain's features, e.g., the beady eyes, the frown) correlate with negative assumptions.
fyi