Many accused of statutory rape claim two things - 1) that the girl consented and 2) that they thought she was older. The first is unimportant - if the girl is underage, it's still rape. But in the US, there is a special defense clause which allows defendents leiniency if there is reasonable evidence they "mistook" a younger girl for one of consenting age. Many times lawyers claim that a girl's makeup or guy's consumption of alcohol impaired the offender's judgement of her age. As an excuse, it's pretty common among men charged with all varieties of sex with a minor. Well, researchers wanted to see if those factors really had an effect on how men (and women) estimated a girl's age. The results are clear: alcohol had no effect on a man's estimate of a girl's age, and makeup had little.
The study, published in the May edition of British Journal of Psychology, took faces from 17 yr old girls and manipulated them to be a little younger and older looking as well as more or less made-up. They then asked 120 sober adults to guess how old and rate how attractive the faces were. The faces which were made to 'look older' did by about 2 years. Those with make-up did look older, but barely. And, across the board, 'younger' faces were deemed more attractive than the 'older' ones.
They then got another 120 adults to different levels of drunk and asked them the same questions. They found that the alcohol did have an effect on attractiveness - the more the participants drank, the hotter a mature girl got, if she was wearing make-up (but they found no effect of alcohol statistically on the attractiveness of immature faces or those without makeup). But one thing that didn't change was the men's ability to estimate age. There was no difference between the age of the photos as estimated by the sober and plastered men. As the authors write, "placed into its forensic context, this study tentatively concludes that alcohol consumption and make-up use do not interfere with age-perception tasks, nor inflate subsequent age estimates." So saying that anything makes a guy mistake an 11 yr old for 19 simply doesn't cut it.
Interestingly, alcohol did make the women perceive the matured faces as younger. And all participants overestimated the girl's ages by about 2.5 years. So there is some validity to guy's arugment (and women's, if made) that they "thought she was older" - just not much. The excuse that make up and alcohol made a girl look four or five years older, however, is just that - an excuse. In reality, guys can still tell a girl's age pretty well when drunk. So while a few beers might make a girl look hotter and make a guy more likely to act on his impulsive desire to sleep with her, he knows that a 12 yr old isn't 18, no matter how much he wants to pretend he doesn't when the cops arrive.
Results like these bring into question the validity of "mistake of age" defenses, especially in cases of statutory rape where the accused is more than 10 years older than the minor. As long as a minor is at least two years younger than the consenting age, it's likely that guys know she's underage. The researchers also pointed out that other cues of age, like tone of voice or language use, aren't factored into this study, so it's possible that men's age estimates are even more accurate in the presence of these variables. At any rate, it seems the excuses for statutory rape are fading fast.
Egan, V., & Cordan, G. (2009). Barely legal: Is attraction and estimated age of young female faces disrupted by alcohol use, make up, and the sex of the observer? British Journal of Psychology, 100 (2), 415-427 DOI: 10.1348/000712608X357858