Proceedings of the Annual Meeting of the Cognitive Science Society

Although much evidence suggests that language influences perceptual discrimination, relatively little research has exploredfactors that might modulate such effects. Some have proposed that effects of language may be stronger for more difficultdiscriminations than for easier ones, yet previous studies have merely assumed this idea or tested it in a manner that treatslanguages influence as all-or-none rather than graded. Here we provide evidence for graded effects of language acrosssystematically varied levels of discrimination difficulty. Using color as a testbed, we show that categorical perceptionen-hanced discrimination at category boundariesincreases with difficulty, defined by the perceptual similarity between colors.Evidence for the modulatory role of difficulty was observed across two different linguistic category boundaries and twodifferent perceptual tasks. Our findings provide insight into the conditions under which language shapes perception andconverge with recent models that consider such effects in probabilistic terms.