Achievement goals are the competence-related aims for which individuals strive in achievement situations. Various empirical studies have shown that achievement goals can predict a wide range of outcomes, including persistency and effort, positive and negative affect during the task, and task performance. However, little is known about what precisely happens when individuals adopt a given type of achievement goal. In this talk, I present the data from two projects that examined the effects of experimentally manipulated achievement goals on memory encoding and on spatial working memory task performance. We found that performance-approach goals (goals that focus on attaining normative competence) have both an undermining effect and a seemingly facilitative effect. The need for future research to consider the metacognitive process during tasks is discussed.