A pragmatic account of referential communication is developed which presents an alternative to traditional Gricean accounts by focusing on cooperativeness and efficiency, rather than informativity. The results of four language-production experiments support the view that speakers can be cooperative when producing redundant adjectives, doing so more often when color modification could facilitate the listener's search for the referent in the visual display (Experiment 1a). By contrast, when the listener knew which shape was the target, speakers did not produce redundant color adjectives (Experiment 1b). English speakers used redundant color adjectives more often than Spanish speakers, suggesting that speakers are sensitive to the differential efficiency of prenominal and postnominal modification (Experiment 2). Speakers were also cooperative when using redundant size adjectives (Experiment 3). Overall, these results show how discriminability affects a speaker's choice of referential expression above and beyond considerations of informativity, supporting the view that redundant speakers can be cooperative.