Sexual arousal though they are generally considered secondary in role to the other three. Erotic stimuli which can result in sexual arousal can include conversation, reading, films or images, or a smell or setting, any of which can generate erotic thoughts and memories in a person. Given the right context, these may lead to the person desiring physical contact, including kissing, cuddling, and petting of an erogenous zone. This may in turn make the person desire direct sexual stimulation of the breasts, nipples, buttocks and/or genitals, and further sexual activity. Erotic stimuli may originate from a source unrelated to the object of
Sexual arousal mechanisms; Goldey and van Anders showed that sexual cognitions impact hormone levels in women, such that sexual thoughts result in a rapid increase in testosterone in women who were not using hormonal contraception. In terms of brain activation, researchers have suggested that amygdala responses are not solely determined by level of self-reported sexual arousal; Hamann and colleagues found that women self-reported higher sexual arousal than men, but experienced lower levels of amygdala responses. During the late 1950s and early 1960s, William H. Masters and Virginia E. Johnson conducted many important studies into human sexuality. In 1966, they published "Human Sexual