In 1991, Cher released her cover of The Shoop Shoop Song (It's In His Kiss) as part of the soundtrack of the movie Mermaids. Here are the opening lyrics:
Does he love me? I want to know
How can I tell if he loves me so?
Is it in his eyes?
Oh no! You'll be deceived
Is it in his eyes?
Oh no! He'll make believe
If you want to know if he loves you so
It's in his kiss
That's where it is
As I have discussed in several of my writings (Saad, 2007, 2011a, 2011b), song lyrics are a window to our evolved sexuality (see my posts here and here on this general point). In the latter song, it would appear that kissing could serve as a means of gauging a romantic partner's feelings. Are there other functions that kissing serves?
Using an evolutionary lens, Susan M. Hughes, Marissa A. Harrison, and Gordon G. Gallup, Jr. explored sex differences across several metrics dealing with romantic kissing. The researchers posited three hypotheses regarding the functional value of romantic kissing, namely to evaluate a mate (e.g., taste and smell), to trigger bonding between the partners, and to generate sexual arousal and the associated interest in having sex.
Across three studies, they tracked differences between men and women along a wide range of measures, a few of which I highlight here (specifically the main effects for sex). For the full set of findings including null effects, see the original paper here.
Findings wherein women scored higher than men:
Importance of breath
Importance of taste in mouth
Importance of kissing before, during, and after sex: women > men (across all three temporal periods)
Importance of kissing throughout a relationship: It decreases for men but remains roughly the same for women (i.e., kissing always matter to women)
Likelihood of initiating kissing after sex
Felt jealousy at the thought of one's long-term partner kissing someone else
The importance of health appearance of teeth in deciding whether to kiss an individual
Findings wherein men scored higher than women:
Likelihood of having sex without kissing
[Interestingly, female sex workers will often proclaim that they refuse to kiss their clients on the lips. Typically, the argument is that it is simply too intimate an act notwithstanding the fact that they are otherwise having sex with the clients!]
How likely should kissing lead to sex
Importance of kissing post fighting
Importance of a wet kiss
Importance of "tongue action"
Likelihood of having short-term sex without kissing
Likelihood of kissing or having sex with someone that one is not attracted to
Likelihood of having sex with a poor kisser
Likelihood of kissing someone that you know does not want a relationship
Likelihood of kissing someone that you know you do not want a relationship with
A good kiss is when a partner lets me initiate "tongue action"
A good kiss is when it leads to sex
A good kiss is when one's partner moans
The importance of face attractiveness in deciding whether to kiss an individual
The importance of body attractiveness in deciding whether to kiss an individual
The importance of body weight in deciding whether to kiss an individual
Conclusion: When it comes to romantic kissing, men and women do indeed view the act through wildly different lenses.
Gad Saad (2007). The Evolutionary Bases of Consumption. Mahwah, NY: Lawrence Erlbaum.
Gad Saad, (2011b). Songs lyrics as windows to our evolved human nature. In Alice Andrews and Joseph Carroll (Eds.), The Evolutionary Review: Art, Science, Culture. Albany, NY: SUNY Press.