The article examines advantages of positive information in social information processing. First, it presents a ubiquitous positivity advantage in processing speed. Then it introduces the density hypothesis as an explanation: Positive information is processed faster because it is more similar to other positive information compared to the overall similarity of negative information. Accordingly, positivity advantages are not only caused by the information’s valence itself, but by a structural property of the information that strongly correlates with valence. Further, the article provides an overview of recent density effects in other social psychology paradigms (i.e., evaluative priming, person perception, and person memory). The final discussion considers possible reasons for the correlation of density and valence, which leads to the observed positivity advantages.