 This study investigated how mice recognize individuals and assign values to them. It was found that mice can differentiate between different individuals by sniffing them, and this ability depends on the dorsal hippocampus. The hippocampus also maintains activity related to reward expectations when mice interact socially, even if they don't know who the other mouse is. Additionally, a subset of hippocampal neurons can accurately identify individual mice with high accuracy. This suggests that the hippocampus may be involved in associating social memories with reward value. This article was authored by Yun Jikong, Kyu Hee Lee, Jong Rock Do, and others.