The article explores how people's performance is influenced by comparing themselves to others, even when working on separate tasks. The study shows that these comparisons can affect individuals' efforts in different ways, either making them work harder when others do well (complements) or less when others excel (substitutes). The research also finds that offering the right monetary incentives can enhance these peer effects, and that it is better for individuals to make their efforts one after the other rather than at the same time.