Many studies have established that people care a great deal about their relative economic position and not solely, as standard economic theory assumes, about their absolute economic position. However, behavioral evidence is rare. This paper provides an empirical analysis on how individuals' relative income position affects their performance. Using a unique data set for 1040 soccer players over a period of eight seasons, our analysis suggests that if a player's salary is below the average and this difference increases, his performance worsens and the productivity decreasing effects of positional concerns are stronger. Moreover, the larger the income differences within a team, the stronger positional concern effects are observable. We also find that the more the players are integrated in a particular social environment (their team), the more evident a relative income effect is. Finally, we find that positional effects are stronger among high performing teams.