128 undergraduates' perceptions of tattoos on a model described as a college instructor were assessed. They viewed one of four photographs of a tattooed or nontattooed female model. Students rated her on nine teaching-related characteristics. Analyses indicated that the presence of tattoos was associated with some positive changes in ratings: students' motivation, being imaginative about assignments, and how likely students were to recommend her as an instructor.
Source: "Perceptions of a tattooed college instructor." from Psychol Rep. 2010 Jun;106(3):845-50.
Hmm, i find this interesting, is this because the professor ties in with the student’s own rebellious phase? plus imagination? plus the sexy factor? Interesting, but I don't think there will be a rash of professors making a beeline for the tattoo parlour, do you?