This study sought to clarify the process of knowledge acquisition by examining why people tend to misattribute others' activities as their own after having interacted with them. In Study 1, an experiment was conducted with 4-year-old children allocated to 2 groups: one group of children interacted with an adult, and the other group interacted with a peer. The latter group was further divided into 2 subgroups on the basis of the strength of children's friendships (high intimacy vs. low intimacy). Children in the low intimacy condition demonstrated more misattributions and greater knowledge acquisition. Study 2 focused on interactions and revealed that knowledge acquisition was influenced by the nature of children's interactions, which depended on the strength of their friendships. Those in the low intimacy condition (i.e., weaker friendships) provided their peers with appropriate support sufficient to complete a task but did not unilaterally complete tasks for their peers. These results suggest that misattribution occurs when individuals actively participate in interactions with others, and that new knowledge is acquired as they internalize the knowledge of others.