The Force Concept Inventory (FCI) has been widely used to assess student understanding of introductory mechanics concepts by a variety of educators and physics education researchers. One reason for this extensive use is that many of the items on the FCI have strong distractor choices which correspond to students' alternate conceptions in…

The study reported here extends the investigation begun by Piaget of content effects to laboratory and naturalistic tasks. If the accuracy and completeness of the subjects' expected variables is related to content, then performance on laboratory and naturalistic tasks should differ systematically. The subjects' expected variables were measured by…