High vowels are generally shorter than low vowels: there is a positive correlation between F1 and duration in English and cross-linguistically (Heffner 1937; Elert 1964; Äimä, 1918). This paper argues that the cross-linguistic height/duration correlation might be explained perceptually: high vowels inherently sound shorter than low vowels. Study 1 analyzed Chilean Spanish vowels to determine whether this correlation is physiological in nature or the result of linguistic rules, finding that the correlation is linguistically-specified. To account for the cross-linguistic occurrence of the correlation, Study 2 tested if speakers perceive shorter high vowels in a forced-choice perception task. Results indicate that high vowels indeed sound shorter, and that this vowel categorization ability is partially learned.