The Science Behind a Kiss

Why do we kiss? And if you really think about it, where does the act of kissing come from? Today, we as a society have grown to perceive kissing as a passionate and loving act between couples, a sign of respect in more formal situations, even sometimes a tad gross! Either way, not a lot of people would look into this as more of a potentially evolutionary behaviour.

Typically, the average human will spend 20,160 minutes of their lives kissing..wow! Not to mention the world record for the longest kiss stands at 58 hours, 35 minutes and 58 seconds. We could even say that kissing is a type of exercise, burning roughly 2-3 calories per minute. Well that could be one way to avoid the gym! Nevertheless, despite Hollywood films and poetry creating a magical view on kissing, researchers insist this natural behaviour is evolutionary and almost animalistic.

If we look at birds and primates, we can observe the act of ‘kiss-feeding’. This action involves mothers passing pre-chewed food from one adult mouth to the infant’s mouth. A bit weird? Well scientifically, the infant is proven to obtain the nutrients which breast milk is not always able to provide. Not to mention, enabling a much easier way for infants to absorb vitamins like B12.

Evolutionary scientists believe that kissing is potentially a way for us to determine our ideal mate. Emer Maguire from Voices Magazine compares this to a type of job interview, seeking out candidates which best match the description. We do so by ‘taste testing’, as our saliva carries information about ourselves including our level of health, and contains mucus membranes that are permeable to hormones such as testosterone. Does this mean that kissing is actually part of ‘survival of the fittest’, and really, a basic reproductive behaviour?

Interestingly, the actress Alicia Silverstone, famously known for her character ‘Cher’ in the popular 90’s film ‘Clueless’, caused quite a bit of controversy on social media as she posted clips of herself kiss-feeding her own infant. Some of the public may have deemed this as weird-looking, but is this because we only know the evolved version of kissing as opposed to the origin?

So will this newly discovered scientific research change the way we think when we next kiss a partner or loved one? And is there a chance that we as humans will go back to kiss-feeding and deem this as more of a normal maternal act? Either way, kissing is a very natural part of our lives and potentially our survival, so pucker up!