F1 correlates with vowel height: the higher the vowel, the lower the F1. There is a positive correlation between F1 and duration in vowels in various languages. In other words, high vowels are shorter than low vowels. This paper revisits that generalization, as well as the question of whether the generalization is phonetic (mechanical, extrinsic) or phonological (controlled, intrinsic). We investigate the vowel duration and height between and within categories in English and Swedish, using F1 as a measure of vowel height. The between-category investigation confirms previous studies: high vowels are shorter than low vowels. However, we did not find the same correlation within categories: a higher instance of the vowel [ɪ] is not shorter than a lower instance of [ɪ]. These results indicate that the correlation between vowel height and duration is not purely mechanical.