The acquisition of formal operational schemata during adolescence: The role of the biconditional

To test the hypothesis that the basic “logic” utilized by individuals in scientific hypothesis testing is the biconditional (if and only if), and that the biconditional is a precondition for the development of formal operations, a sample of 387 students in grades eight, ten, twelve, and college were administered eight reasoning items. Five of the items involved the formal operational schemata of probability, proportions and correlations. Two of the items involved propositions and correlations. Two of the items involved propositional logic. One item involved the biconditional. Percentages of correct responses on most of the items increased with age. A principal-component analysis revealed three factors, two of which were identified as involving operational thought, one of which involved propositional logic. As predicted, the biconditional reasoning item loaded on one of the operational thought factors. A Guttman scale analysis of the items failed to reveal a unidimensional scale, yet the biconditional reasoning item ordered first supporting the hypothesis that it is a precondition for formal operational reasoning. Implications for teaching science students how to test hypotheses are discussed.     

Predicting genetics achievement in nonmajors college biology

Students enrolled in a non-majors college biology course were pretested to determine their level of intellectual development, degree of field independence, mental capacity, amount of prior genetics knowledge, and amount of fluid intelligence. They were then taught a unit on Mendelian genetics. The only student variables found to not account for a significant amount of variance on a test of reading comprehension and/or a test of genetics achievement was amount of prior genetics knowledge. Developmental level was found to be the most consistent predictor of performance, suggesting that a lack of general hypothetico-deductive reasoning ability is a major factor limiting achievement among these students.     

Hypothetico-deductive reasoning skill and concept acquisition: Testing a constructivist hypothesis

This study tested the constructivist hypothesis that the acquisition of domain-specific conceptual knowledge (declarative knowledge) requires use of general procedural knowledge. More specifically, it was hypothesized that use of a general pattern of hypothetico-deductive reasoning is necessary for the acquisition of novel domain-specific concepts. To test this hypothesis 314 high school biology and chemistry students were first tested to determine whether or not they were skilled in the use of hypothetico-deductive reasoning. Based on this test, students were classified as reflective, transitional, or intuitive thinkers. All students were then presented with a series of four concept-acquisition tasks. It was predicted that reflective (hypothetico-deductive) thinkers would acquire the concepts while intuitive (empirico-inductive) thinkers would not. Transitional thinkers were expected to be partially successful. These predictions were confirmed as skill in hypothetico-deductive reasoning (developmental level), but not age, was highly correlated with performance on the concept acquisition tasks (X² = 71.14, p < 0.00001). This result was interpreted to be supportive of the constructivist hypothesis.     

Biomechanics of elite recumbent handcycling: a case study

In the presented research, a kinematic and electromyographic study was performed on one world-class male elite handbiker (UCI class H3.2). Activity of 14 muscles of the upper body were measured with surface electromyography (EMG), and a motion analysis of the athlete’s movement was performed concurrently for different backrest positions, crank lengths, and crank heights at three power levels (130, 160 and 190 W). Kinematics in terms of elbow and wrist angle, muscular on-off timing, EMG amplitudes, and integrated EMG were calculated. Results showed that little changes occurred for kinematic parameters and changes in position led to a shift in muscular timing. However, no indication for immediate improvement to the athlete’s preferred original position could be observed.     

Use of reasoning to a contradiction in grades three to college

The primary purpose of this study was to test the hypothesis that an important intellectual acquisition during adolescence is the ability to generate arguments that involve reasoning to contradiction. Students in grades 3, 5, 7, 9, 11, and college were individually administered a four-card selection task that required them to, among other things, reason to a contradiction to falsify a hypothesis. Virtually none of the students spontaneously utilized this reasoning pattern on the initial task. Minimal verbal instruction in use of the reasoning pattern was then given followed by a logically analogous selection task. Performance on this task improved significantly with age from 12% success among third graders to 52% success among college students, providing some support for the hypothesis. Performance on an evaluation task showed similar rates of success; however, most students were able to correctly evaluate falsifying evidence when presented. This result suggested that, contrary to Piagetian theory, students from grade 3 upward comprehend the logic of falsification. It is argued that reasoning to a contradiction is a reasoning pattern of central importance in testing alternative scientific hypotheses and its use in students grades 3 through college could be enhanced through proper instruction and, if done, should increase students' ability to generate and evaluate competing hypotheses.     

DigitalHub: A Repository Focused on the Future

The DigitalHub scholarly repository was developed and launched at the Galter Health Sciences Library for the Feinberg School of Medicine and the greater Northwestern Medicine community. The repository was designed to allow scholars the ability to create, share, and preserve a range of citable digital outputs. This article traces the evolution of DigitalHub’s development and engagement activities, highlighting project challenges, innovations, success stories, and the team-based approach that was employed to successfully achieve project goals.     

Advancing research beyond the ruling theory stage

Seldom do researchers in science education state causal hypotheses they seek to test. Even less often are alternative hypotheses stated, much less tested. Further, science education researchers as a rule confuse hypotheses with predictions. Thus, they stand little chance of conducting research which distinguishes among alternative explanations, and consequently stand little chance of advancing knowledge beyond the Ruling Theory Stage of thinking. The present article offers five research criteria and their rationale intended to help researchers avoid these problems and help them conduct higher-quality research, which should in turn improve the quality of science teaching.     

Sound and faulty arguments generated by preservice biology teachers when testing hypotheses involving unobservable entities*

A sample of preservice biology teachers (biology majors) enrolled in a teaching methods course formulated and attempted to test six hypotheses to answer a causal question about why water rose in a jar inverted over a burning candle placed in a pan of water. The students submitted a lab report in which arguments and evidence for testing each hypothesis were presented in an if/then/therefore hypothetico‐predictive form. Analysis of written arguments revealed considerable success when students were able to manipulate observable hypothesized causes. However, when the hypothesized causes were unobservable, such that they could be only indirectly tested, performance dropped, as shown by use of three types of faulty arguments: (a) arguments that had missing or confused elements, (b) arguments whose predictions did not follow from hypotheses and planned tests, and (c) arguments that failed to consider alternative hypotheses. Science is an enterprise in which unobservable theoretical entities and processes (e.g., atoms, genes, osmosis, and photosynthesis) are often used to explain observable phenomena. Consequently, if it is assumed that effective teaching requires prior understanding, then it follows that these future teachers have yet to develop adequate hypothesis‐testing skills and sufficient awareness of the nature of science to teach science in the inquiry mode advocated by reform guidelines. © 2002 Wiley Periodicals, Inc. J Res Sci Teach 39: 237–252, 2002