Competence and performance revised: pragmatic development may shape mentalizing development

Cognitive development research distinguishes between what children know (competence) and their ability to demonstrate their knowledge (performance). An experiment can fail to reveal a child’s competence if its design limits the child’s performance. This distinction allows researchers to design experiments that limit the impact of performance factors, leading to observations of competence earlier in cognitive development. The distinction is often used in a deflationary way, where performance factors are taken to be extraneous to the competence of interest, so that they are irrelevant to a theory of competence. Using the role of children’s pragmatic inferences in mentalizing development as a case, I argue that this is sometimes an implausible use of the distinction. Performance factors do not necessarily support deflationary explanations and so are not always extraneous. I develop the concept of a learning procedure which specifies the attentional and inferential constraints that govern the construction of children’s developing competences. Changes in children’s pragmatic inferences can critically reshape learning procedures with developmental consequences for mentalizing. This case has the wider implication that performance factors split into two kinds. Synchronic performance factors are extraneous to competence and track competence at a specific time. Diachronic performance factors are developmentally entangled with competence and affect competence over developmental time. I outline how these two kinds of performance can be teased apart empirically.