The prolonged VOT (i.e. aspiration) of voiceless stops in English has been proposed by Kiparsky (1979), Withgott (1982), and Jensen (2000) to be linked to the left edge of (recursive) prosodic feet, condensing the disparate environments of aspiration in English (e.g. onset of word-initial and stressed syllables) into a single description based on prosodic structure. This paper shows the results of a production study of voiceless stops in all different possible environments, which finds that the level of aspiration in the onset of the second syllable in lapse environments (e.g. (lolla)([p]a(looza)), (A(meri))[k]a)) is similar, and falls between that of stronger aspirated environments and that of non-aspiration environments. A subsequent categorical perception study finds that both environments behave as an unaspirated environment does, while a gradient perception study finds the result predicted by the prosodically-based theory: the word-medial lapse environment behaves as other aspirated ones do, while the word-final lapse environment behaves as non-aspirated ones do. This paper provides acoustic evidence in support of the phonological definition of categorical aspiration as prosodically-motivated in English.