The Social Penetration theory was developed in 1973 and focuses on the concept of self disclosure. As such, relationships deepen only when members of said relationship reveal increasingly more intimate details about their inner lives with one another through disclosure. One can think of this theory almost like an onion. At first, only the outer, most superficial layer of an individual is visible to the outside world. However, as two people spend additional time together, the layers of the onion begin to peel and both individuals within the relationship are able to see one another’s deeper and deeper layers. One inherent aspect to this theory is that self disclosure is the only means in which an individual can develop deep relationships. And, because vulnerability walks hand in hand with self disclosure there is a certain amount of vulnerability required on the part of the person doing the disclosing to another in order to enhance or grow a relationship. For example, two people in a relatively new friendship may be setting up a plan to spend time together. One friend might suggest a trip to the zoo. The other may be afraid of birds and think of a day at the zoo as an absolutely harrowing experience. The person afraid of birds would need to disclose their fear in the hopes of not being judged if they want to further the relationship. Otherwise their friend may mistake the anxiety for something else. They may think the budding friend does not want to spend time with them or is not as committed to the friendship. Ultimately, being truthful about ones preferences leads to healthier and deeper friendships.

Although romantic relationships are not the only considerations directly discussed in the theories of social relationships, they provide another interesting example of the viewpoint at work, particularly when considering how relationships remain fluid conceptualizations. Some relationships show a faster rate of growth at the beginning and those that maintain for the long term undergo periods of slowing in which partners open up less rapidly to one another. Many theories in romantic relationships highlight this same thinking. The “honeymoon phase” for example represents a period in which a newlywed couple happily undergoes self-imposed transgressions in which they rapidly share information to their new marriage partner. Similarly, many couples experience a time in which this introduction of new information slows and the couple may feel less and less close for a period. According to the Social Penetration Theory, this is because they have shared all of the superficial aspects and even some of the more deeply ingrained aspects of themselves but may have a reached a point in which they are too vulnerable to continue sharing. Essentially, what is left to share has become a trickle at the bottom of a well and each partner now maintains that water supply to quench his or her own needs.