A controlled field experiment investigates order picking performance in terms of productivity. We examined three manual picker-to-parts order picking methods (parallel, zone, and dynamic zone picking) under two different incentive systems (competition-based vs. cooperation-based) for pickers with different regulatory foci (prevention-focus vs. promotion-focus). The study was carried out in a warehouse erected especially for the purposes of order picking research. Our results show that when using a parallel picking method, a competition-based incentive system increases productivity compared to a cooperation-based incentive system, and that when using a zone picking method it is more productive to use a cooperation-based incentive system. This pattern of results was especially pronounced for pickers with a dominant promotion focus. Dominantly, prevention-focused pickers were more productive in zone picking with a cooperation-based incentive system than a competition-based incentive system, but in the other two picking methods the incentive systems delivered a similar productivity performance. No effects on order picking quality were identified. The analyses demonstrate that by aligning order picking methods, incentive systems, and regulatory focus, warehouses can substantially improve productivity.