Lips may have evolved first for food and later applied themselves to
speech, but in kissing they satisfy different kinds of hungers. Whatever the reasons why generations of lovers engaged in the act of openmouthed snogging, it seems that the mutual caressing of lips and the exchange of saliva changes the levels of the bonding hormone oxytocin released into the bloodstream from the brain !!!
what does a kiss tell you about a potential partner !! ? does it stimulate your sex drive?(motivates you to seek range of partners!!) ,Romantic love ?! (motivates you to focus your mating energy on one individual at a time)or long term attachments( motivates you to sustain a pair bond at least long enough to rear a single child through infancy together.??!!