Judgments about future memory performance (metamemory judgments) are known to be susceptible to illusions and bias. Here we asked whether metamemory judgments are affected, like many other forms of judgment, by numerical anchors. Experiment 1 confirmed previous research showing an effect of informative anchors (e.g., past peer performance) on metamemory monitoring. In four further experiments, we then explored the effects of uninformative anchors. All of the experiments obtained significant anchoring effects on metamemory monitoring; in contrast, the anchors had no effect on recall itself. We also explored the anchoring effect on metamemory control (restudy choices) in Experiment 4. The results suggested that anchors can affect metamemory monitoring, which in turn affects metamemory control. The present research reveals that informative and, more importantly, uninformative numbers that have no influence on recall itself can bias metamemory judgments. On the basis of the current theoretical understanding of the anchoring effect and metamemory monitoring, these results offer insight into the processes that trigger metacognitive biases.
Keywords: Anchoring; Informative; Metamemory control; Metamemory monitoring; Uninformative.