Though Roberts and Dunbar found that family relationships withstand the test of time, participants in their study still contacted friends more frequently than kin. Adults generally tend to expend more energy on friendships than family relationships, knowing that family ties are already strong and that maintaining friendship requires more contact.

A study by Applications Research at Motorola found that participants in a family household were more likely to control their availability to family members outside the household via phone or email. Participant communication was often due to a sense of obligation, and it often had a goal-oriented focus, such as a phone conversation to determine a meeting time and place. Participants admitted to avoiding communication with specific family members outside of the home whom they disliked or did not want to see. But though the study included close friends, participants did not experience as much anxiety surrounding communication with friends via technology or explicitly avoid communication with friends. This shows that friends are more likely to agree on set boundaries than family members, who may disagree about how much contact they should have.

Though family members may have many similarities, some family members are very different from each other in personality, taste or behavior. An article by Dena Kemmet of North Dakota State University’s Consumer and Family Sciences Extension Program argues that teenagers choose peers who are like themselves, thus giving them social units that mirror their tastes and personalities. Though peers provide an important support system for teens, Kemmet says this does not mean that parents grow any less important to their children during the adolescent years.

Roberts and Dunbar found that individuals in their study with larger families were likely to have larger networks of friends as well, with a lower level of emotional closeness overall. Individuals with smaller family networks were likely to have a small but emotionally close network of friends. In a similar vein, Andrew Ledbetter of Ohio State University found in a 2009 study that family-communication patterns predicted adult patterns of communication with friends. For example, young adults with more conversational families maintained a greater amount of face-to-face interaction in extra-familial relationships than those with less-conversational families.