The issue of how people use their metacognitive judgments about what they know and how well they know it to take control over their own learning is of primary concern in this article. The fact that in many situations people have relatively accurate metacognitions is well documented (Brown, 1978;, 1997 Gnmeberg & Monks, 1974; Jacoby, Bjork, & Kelley, 1993;Johnson, 1988;Johnson & Raye, 1981;King, Zechmeister, & Shaughnessy, 1980;Koriat, 1975Koriat, , 1993Koriat, , 1995Koriat, , 1997Koriat, , 1998Koriat & Goldsmith, 1996, 1998Leonesio & Nelson, 1990;Lovelace, 1984; Mazzoni, Cornoldi, Tomat, & Vecchi, 1997;Mazzoni & Nelson, 1995;Metcalfe, 1986aMetcalfe, , 1986b Metcalfe, Schwartz, & Joaqnim, 1993;Metcalfe & Weibe, 1987;Nelson, 1988;Nelson & Dunlosky, 1991Nelson, Leonesio, Landwehr, & Narens, 1986;Schwartz & Metcalfe, 1994;Schwartz & Smith, 1997;Smith, Brown, & Balfour, 1991;Thiede & Dunlosky, 1994; Vesonder & Voss, 1985; Wldner & Smith, 1996;Widner, Smith, & Graziano, 1996). Ease-of-learning judgments (EeLs; Underwood, 1966), feeling-of-knowing judgments (FIGs;Hart, 1965;Nelson, Leonesio, Shimamura, Landwehr, & Narens, 1982), and judgments of difficulty (JODs) or of learning (JOLs; Arbuckle & Cuddy, 1969;Gardiner & Klee, 1976;Groninger, 1979;King et al., 1980;Lovelace, 1984) generally have been shown to predict subsequent memory performance with above-chance accuracy. Having established that Lisa K. Son and Janet Metcalfe, Department of Psychology, Columbia University.This research was supported by National Institute of Mental Health Grant 48066. We would like to thank Ozlem Ayduk, Brady Butterfield, Rodolfo Mendoza-Denton, Jasia Pietrzak, and Lisa Schwartz for their help. We also appreciate the comments of Thomas O. Nelson, Keith Thiede, and an anonymous reviewer on a draft of this article.Correspondence concerning this article should be addressed to Lisa K. Son, Department of Psychology, 406 Schermerhorn Hall, Columbia University, New York, New York 10027. Electronic mail may be sent to son@psych.columbia.edu. people appear to have access to accurate metalmowledge, the question of how they put that knowledge to use is becoming focal.Some theories indicate that metacognitions play a central role in a variety of cognitive tasks, including memory retrieval (Reder, 1987;Reder & Ritter, 1992), initial memory encoding (Metcalfe, 1993), problem solving (Metcalfe, 1986b;Simon & Newell, 1971), and self-directed learning . As was assumed by early researchers such as Flavell (1979) and Flavell and Wellman (1977), these self-reflective processes are crucial in controlling and guiding human cognition (see Metcalfe, 1996, in press, for review). Recently, investigators have begun intensively and systematically to explore the question of primary interest in this article: How do people use these metacognitive judgments to control their study-time allocation and hence to determine what it is that they will learn?Interest in the control functions of people's metacognitions was fostered by a framework for human metacognition forw...