This study investigates a severe form of segmental reduction known as contraction. In Taiwan Mandarin, a disyllabic word or phrase is often contracted into a monosyllabic unit in conversational speech, just as “do not” is often contracted into “don’t” in English. A systematic experiment was conducted to explore the underlying mechanism of such contraction. Preliminary results show evidence that contraction is not a categorical shift but a gradient undershoot of the articulatory target as a result of time pressure. Moreover, contraction seems to occur only beyond a certain duration threshold. These findings may further our understanding of the relation between duration and segmental reduction.