There are few words in the English language that have more varied interpretations than diversity. What does diversity mean? Better yet—what does diversity mean to you? And what does it mean to your friends, your professor, your family members, your employer, or the person standing behind you in a grocery store?

As we’ll use the term here, diversity refers to the great variety of human characteristics—ways that we are different even as we are all human and share more similarities than differences. These differences are an essential part of what enriches humanity. Aspects of diversity may be cultural, biological, or personal in nature. Diversity generally involves things that may significantly affect some people’s perceptions of others—not just any way people happen to be different. For example, having different tastes in music, movies, or books is not what we usually refer to as diversity.

Surface diversity and deep diversity are categories of personal attributes—or differences in attributes—that people perceive to exist between people or groups of people.

Surface-level diversity refers to differences you can generally observe in others, like ethnicity, race, gender, age, culture, language, disability, etc. You can quickly and easily observe these features in a person. And people often do just that, making subtle judgments at the same time, which can lead to bias or discrimination. For example, if a teacher believes that older students perform better than younger students, she may give slightly higher grades to the older students than the younger students. This bias is based on perception of the attribute of age, which is surface-level diversity.

Deep-level diversity, on the other hand, reflects differences that are less visible, like personality, attitude, beliefs, and values. These attributes are generally communicated verbally and non-verbally, so they are not easily noticeable or measurable. You may not detect deep-level diversity in a classmate, for example, until you get to know him or her, at which point you may find that you are either comfortable with these deeper character levels or perhaps not. But once you gain this deeper level of awareness, you may focus less on surface diversity. For example, at the beginning of a term, a classmate belonging to a minority ethnic group whose native language is not English (surface diversity) may be treated differently by fellow classmates in another ethnic group. But as the term gets under way, classmates begin discovering the person’s values and beliefs (deep-level diversity), which they find they are comfortable with. The surface-level attributes of language and perhaps skin color become more transparent as comfort is gained with deep-level attributes.

The multiple roles we play in life—student, sibling, employee, child, parent, partner, for example—are only a partial glimpse into our true identity. Have you ever tried to define yourself in terms of the sum of your parts?

According to the American Psychological Association, personal identity is an individual’s sense of self defined by (a) a set of physical, psychological, and interpersonal characteristics that is not wholly shared with any other person and (b) a range of affiliations (e.g., ethnicity) and social roles. Your identity is tied to the most dominant aspects of your background and personality. It determines the lens through which you see the world and the lens through which you receive information.

To better understand identity, consider how social psychologists describe it. Social psychologists, those who study how social interactions take place, often categorize identity into four types: personal identity, role identity, social identity, and collective identity.

• Personal identity captures what distinguishes one person from another based on life experiences. No two people, even identical twins, live the same life.
• Role identity defines how we interact in certain situations. Our roles change from setting to setting, and so do our identities. At work, you may be a supervisor; in the classroom, you are a peer working collaboratively; at home, you may be the parent of a ten-year-old. In each setting, your bubbly personality may be the same, but how your coworkers, classmates, and family see you is different.
• Social identity shapes our public lives by our awareness of how we relate to certain groups. For example, an individual might relate to or identify with Korean Americans, Chicagoans, Methodists, and Lakers fans. These identities influence our interactions with others. Upon meeting someone, for example, we look for connections as to how we are the same or different. Our awareness of who we are makes us behave a certain way in relation to others. If you identify as a hockey fan, you may feel an affinity for someone else who also loves the game.
• Collective identity refers to how groups form around a common cause or belief. For example, individuals may bond over similar political ideologies or social movements. Their identity is as much a physical formation as a shared understanding of the issues they believe in. For example, many people consider themselves part of the collective energy surrounding the #metoo movement. Others may identify as fans of a specific type of entertainment such as Trekkies.