Social penetration theory was developed by fellow psychologists Dalmas Taylor and Irwin Altman in their 1973 article Social Penetration: The Development of Interpersonal Relationships. Social penetration theory (SPT) posits that as a relationship develops, shallow and non-intimate communication evolves and becomes deeper and more intimate.
Understanding social penetration theory
In essence, Taylor and Altman discovered that the more time we spend with others, the more likely it is that each of us will disclose personal or intimate details about our lives.
The pair is also credited with the now infamous onion metaphor, which describes the idea that personality is multi-layered and must be “peeled back” one layer at a time.
Described in more scientific terms, the onion metaphor serves as a framework for a process called social penetration.
This is a broad concept that describes the behavior in a social interaction and also the self-reflection that occurs before, during, and after the interaction itself.
Behavior may be:
- Verbal – the exchange of information via words.
- Non-verbal – where information is exchanged through body language such as facial expression and posture, and
- Environmental – that is, how do the individuals utilize the space? How much distance is there between each person? Are they interacting with physical objects in the area?
When communication takes place, the individual receiving information uses these behaviors to form a subjective opinion of the other.
Rather than consider positive or negative behaviors in isolation, the individual assesses them collectively as the basis for forming a social bond.
Social penetration theory also considers the rewards and costs of social penetration and has influenced multiple information management and relationship development-based theories.
The four stages of social penetration theory
As hinted at in the previous section, social penetration is a linear, one-way process that progresses at its own pace over time.
This progression can be explained across four stages:
Orientation
The orientation stage is where two strangers meet and first start to form an impression of each other.
This stage is characterized by pleasantries, small talk, and other topics that are considered socially acceptable or non-offensive.
Exploratory affective
In the second stage, a casual friendship may form if each individual finds the other agreeable.
The friendship is characterized by both revealing aspects of themselves, expressing their opinions, and asking the other to do the same. Note that the relationship nevertheless sticks to safer topics such as movies or sport.
Affective
Another layer of the onion is peeled off in the affective stage as the relationship becomes more intimate and substantive.
Here, some personal information is revealed but the disclosure tends to be more fun and spontaneous than serious and restrained.
The two individuals may joke, make sarcastic remarks, or create nicknames for each other. Healthy conflict may also occur in the affective stage.
Stable exchange
In the final stage, the layers of an individual’s personality have been stripped away to reveal the authentic person beneath.
Conversational topics are characterized by breadth, depth, and openness, with both feelings comfortable expressing their thoughts, behaviors, and beliefs without fear of persecution.
Few relationships are maintained to this extent. Indeed, most are reserved for close friends, family members, and romantic partners.
Social Penetration Theory vs. Uncertainty Reduction Theory

Whereas the Uncertainty Reduction Theory suggests, people are uncomfortable with uncertainty and seek ways of predicting the trajectory of social interactions.
According to this theory, individuals leverage seven axioms to reduce uncertainty during communication:
- Verbal communication.
- Non-verbal warmth.
- Information seeking.
- Self-disclosure.
- Reciprocity.
- Similarity.
- Liking.
Whereas social penetration theory is also a linear-communication theory that explains how relationships move from shallow to deeper and more intimate as they go through four distinct stages: orientation, exploratory affective, affective, and stable exchange.
Social Penetration Theory vs. Social Exchange Theory

In a social exchange theory, individuals deal with each other simply looking at two factors:
This is a highly simplified and economical/materialistic view of relationships.
While this is a much-simplified version than also Social Penetration Theory, this might work well in a business context, where many relationships are modeled around the economic incentives built into the relationship.,
In other words, the social penetration theory gives a more subtle view of human relationships.
The social exchange theory implies a much-simplified view, which is more limited, yet it might help to better model relationships at scale within organizations, especially in structuring employees’ relationships.
Of course, this theory must be balanced with other more comprehensive theories like Social Penetration or the Uncertainty Reduction Theory.
Key takeaways
- Social penetration theory posits that as a relationship develops, shallow and non-intimate communication evolves and becomes deeper and more intimate.
- Social penetration theory is based on the idea of social penetration, a broad concept describing various verbal, non-verbal, and environmental factors that impact relationship development.
- Social penetration theory has four distinct stages: orientation, exploratory affective, affective, and stable exchange. The final stage represents the sort of deep relationship a person normally maintains with a close friend, family member, or spouse.
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