Colexification refers to the phenomenon of multiple meanings sharing one word in a language . Cross-linguistic lexification patterns have been shown to be largely predictable, as similar concepts are often colexified . We test a recent claim that, beyond this general tendency, communicative needs play an important role in shaping colexification patterns . We approach this question by means of a series of human experiments, using an artificial language communication game paradigm . Our results across four experiments match the previous cross-linguistic findings: all other things being equal, speakers do prefer to colexify similar concepts . However, we also find evidence supporting the communicative need hypothesis: when faced with a frequent need to distinguish similar pairs of meanings, speakers adjust their colexification preferences to maintain communicative efficiency, and avoid colexifying those similar meanings which need to be distinguished in communication . This research provides further evidence to support the argument that languages are shaped by the needs and preferences of their speakers.