Two experiments investigated the acquisition of English comparative adjective forms, Adj+er and more Adj. In Experiment 1, 72 children, four- and seven-years-old, indicated their preferences for the synthetic or periphrastic comparative form for 16 adjectives in a forced-choice judgement task; their responses were compared to those of a group of adults (Graziano-King, 2003). In Experiment 2, a group of 29 children, ranging in age from 5;1 to 10;9, and a group of 11 adults performed a forced-choice judgement task, similar to that of Experiment 1, and an elicited production task, responding to the same 32 adjectives for both tasks. The two studies together support an acquisition trajectory of three stages. In the first stage, children show no preference for either form of the comparative; in the second, they adopt a suffixation rule; and in the third, they abandon the general rule and become conservative learners, eventually reaching the adult target.