Extends prior theory and research by postulating the existence of an intermediate class of concepts called 'hypothetical'. Investigates the hypothesis that three kinds of scientific concepts exist by constructing and administering a test on concepts introduced in a college biology course. Supports the hypothesis that intellectual development…

Investigated was the relation between student ability to translate sentences into equations, equations into sentences, and student performance in formal operational reasoning, proportional reasoning, and introductory-level chemistry. Results indicate that students who lack formal operational skills may experience problems in the translation of…

Reports a study of 922 college students that classified the students based on performance on formal operational reasoning tasks. Students were also administered seven logic tasks. Response patterns were analyzed and found to be similar to patterns derived from the multiple-hypothesis theory of advanced scientific reasoning and different from those…

Presented is a study in which students' intellectual reasoning development was evaluated following instruction that emphasized formal operations in a traditional lecture format. Results indicated that formal-operational students had significantly more success in the three reasoning areas than transitional students and transitional students had…

Reports a study that analyzes the importance of individual difference variables in explaining subject performance in formal reasoning in 72 first-year college students. (PR)