‘Love like you’ve never been hurt.’ –Mark Twain


Explicit communication involves the deliberate, conscious choosing of words and signals to convey a specific message to a recipient or target audience. […] Much of human communication is also implicit, and occurs subconsciously without overt individual attention. Examples include nonverbal communication and subconscious facial expressions, which have been argued to contribute significantly to human communication and understanding. […] Additionally, recent studies conducted by evolutionary psychologists and biologists have revealed that other animals, including humans, may also communicate information implicitly via the production and detection of chemical olfactory cues. Of specific interest to evolutionary psychologists has been the investigation of human chemical cues indicating female reproductive status. These subliminally perceived chemical cues (odors) are often referred to as pheromones.

For two decades, psychologists studying ovulation have successfully employed a series of “T-shirt studies” supporting the hypothesis that men can detect when a woman is most fertile based on olfactory detection of ovulatory cues. However, it is not known whether the ability to detect female fertility is primarily a function of biological sex, sexual orientation, or a combination of both.

Using methodologies from previous T-shirt studies, we asked women not using hormonal contraceptives to wear a T-shirt for three consecutive nights during their follicular (ovulatory) and luteal (non-ovulatory) phases. Male and female participants of differing sexual orientations then rated the T-shirts based on intensity, pleasantness, and sexiness.

Heterosexual males were the only group to rate the follicular T-shirts as more pleasant and sexy than the luteal T-shirts. Near-significant trends also indicated that heterosexual men and non-heterosexual women consistently ranked the T-shirts, regardless of menstrual stage, to be more intense, pleasant, and sexy than did non-heterosexual men and heterosexual women.

{ Journal of Social, Evolutionary, and Cultural Psychology | PDF }