Revealing private information about your self to others is known as self-disclosure (Wheeless, 1978). Self-disclosure is a key part of building and sustaining relationships (Reis & Patrick, 1996). When you disclose to someone, you reveal aspects of your self that you previously kept hidden. Psychologists Irwin Altman and Dalmas Taylor (1973) think of self-disclosure as similar to peeling back layers of an onion. According to their social penetration theory, the self is an “onion-skin structure” consisting of three sets of layers. The outermost layers of your self are demographic characteristics, such as your birthplace, age, gender, and ethnicity (see Figure 10.1). When you meet someone for the first time, you typically focus the conversation on these characteristics: What’s your name? What’s your major? Where are you from? The intermediate layers contain your attitudes and opinions about things like music, politics, food, and entertainment. Deep within the onion are the central layers of your self—core characteristics such as self-awareness, self-concept, self-esteem, personal values, fears, and distinctive personality traits. As Chapter 2 discusses, this is what makes up your self.

This notion that the self consists of layers helps explain how to distinguish between casual and close involvements. As relationships progress, partners start peeling down to the deeper layers of the onion, disclosing increasingly personal information to each other. But in addition to depth, the revealing of selves that occurs during relationship development involves breadth—sharing more aspects of your self at each layer. For example, when you’re sharing your attitudes and opinions (the intermediate layers of your self), you would be demonstrating breadth if you covered a relatively wide range of topics instead of discussing in detail only your taste in music.

The deeper and broader self-disclosure becomes, the more it fosters intimacy—feelings of closeness between you and others (Mashek & Aron, 2004). Intimacy is self-perpetuating: the more intimacy you feel, the more you disclose; and as you disclose more, feelings of intimacy deepen (Shelton, Trail, West, & Bergsieker, 2010). But for self-disclosure to create intimacy, several conditions must be met (Reis & Shaver, 1988). For one thing, both partners must disclose. If one person shares previously private thoughts and feelings, and the other person doesn’t, the relationship isn’t intimate—it’s one-sided.

The partner who is listening to someone self-disclose must also respond supportively. Have you ever shared something deeply personal with a friend, who then commented with something like “I can’t believe you did something so stupid!” If so, how did this response make you feel? Chances are it created a feeling of distance rather than one of closeness between the two of you.

Finally, to foster feelings of intimacy with others, it’s important to disclose information that people view as appropriate. Sharing information that is perceived as problematic or peculiar can damage relationships (Planalp & Honeycutt, 1985). Imagine that a coworker tells you he’s obsessed with serial killers. You probably won’t feel closer to him—unless you share the same obsession!