Recent work in the field of evolutionary psychology has shown that "group membership" is a very important attribute in the human perception of other humans. Like gender and age, group membership is encoded in memory quickly, involuntarily, and persistently---so much so that it has been hypothesized that humans have evolved specialized neural circuitry to process these characteristics. Moreover, humans are extremely sensitive---although largely subconsciously---to cues (physical, linguistic, pragmatic, etc) that are statistically correlated with group membership. Thus, these superficial characteristics will be attended to, to the extent that they are indicative of the social dynamics of a community.
These findings have implications for at least three broad domains of queer study / activism. First, they can provide insight into the origins and persistence of popular stereotypes of GLBT people; likewise, this aspect of cognitive processing could be responsible for "gaydar"---the attested sensitivity GLBT people have for other GLBT people.
Second, the perception of in-group and out-group ("us and them") is reinforced by positive images as well as negative. Thus, while rallies, protests, marches, Pride festivals, and dedicated TV channels all build much needed community strength and solidarity (effective for bringing about institutional change), it also reinforces social boundaries that hamper cultural change.
Finally, and perhaps most importantly, these findings imply that social perceptions of group membership are hierarchical in nature and their relative weight is dependent on context. Meaningful shifts in attitude are more likely to occur when there is a unifying perception of membership that supersedes the queer/straight barrier. As a trivial example, consider the families of GLBT individuals: close family members are more likely to experience radical changes in their perceptions of homosexuality or gender-identity issues because of a shared personal relationship with a GLBT person.
It should be possible through careful planning and timing to manipulate social circumstances to facilitate meaningful cultural as well as institutional change.
Kurzban, R., J. Tooby, and L. Cosmides. 2001. Can race be erased? Coalitional computation and social categorization. Proceedings of the National Academy of Science, 98(26):15387–15392.
Rogers, Everett. 1995. Diffusion of Innovations (4th Ed.). The Free Press, New York.