Decomposing Water-Level Responses: Field Effects as Separate Influences

A previous study on water-level task performance using binomial mixture analyses showed that subgroups of subjects could be identified which used different response rules. Some subjects used a bottom parallel rule, others used a random-like rule, and still others used the correct response rule. The present study relates the water-level task performance of these subgroups to field effect influences. Subjects were 604 children and adolescents aged 7 to 15 years who responded to eight water-level and eight rod-and-frame task items. The results show that the water-level response distribution is influenced by the frame of the vessel. These field effects are relatively small if subjects maintain a fixed response rule, and they are large if subjects use a nonfixed random rule. Both field effects and response rules contribute to the behavior of subjects responding to water-level task items.