Processing errors in conditional and biconditional problem solving behavior

Students (N = 237) in each of grades 8, 10, 12, and 14 were randomly divided into three groups and administered either a 16-item multiple-choice test of conditional syllogisms, or a 16-item test of biconditional syllogisms, or a 32-item test with both conditional and biconditional syllogisms. Results provided within experiment and within-subjects comparison of responses on conditional and biconditional syllogisms. A comparison of response patterns on conditional items with responses on actual biconditional items provided a direct test of the previously hypothesized biconditional misinterpretation of conditional problems. These analyses confirmed the strong tendency of subjects (across grades) to interpret conditional syllogisms biconditionally. Surprisingly, performance on biconditional problems does not improve systematically with age; in fact, college sophomores perform only slightly better than eighth graders. With regard to conditional syllogisms, results confirmed previously described performance variations across forms of both major and second premises and also replicated an unusual reversed developmental trend on the problem which involves denying the consequent.     

Extinction of a taste aversion in the absence of the consummatory response

Rats were initially conditioned to avoid saccharin presented orally and were then given 40 intravenous injections of saccharin or saline. Those injected with saccharin showed more rapid extinction of the aversion to saccharin presented orally. Results are related to studies of shock avoidance using curarized subjects.     

Motivation profiles in sport: a self-determination theory perspective

The present study examined the link between motivation profiles among adult sports participants and the consequences of enjoyment, effort, positive and negative affect, attitude toward sport participation, intention to continue sport participation, satisfaction, and frequency of attendance in sport. Two samples of participants (n = 590 and n = 555) completed the Sport Motivation Scale and a range of self-report measures to assess the outcome variables. Exploratory cluster analyses applied to Sample 1 and confirmatory cluster analysis applied to Sample 2 identified two clusters of sport participants. The first comprised participants with high scores on both nonself-determined and self-determined motives. The second comprised participants with high scores on self-determined motives but low scores on nonself-determined motives. Participants in the first cluster scored higher on all outcome variables. The results are discussed with reference to a more in-depth understanding of the motivation dynamics of sport participation based on Self-Determination Theory.     

Getting to Evo-Devo: Concepts and Challenges for Students Learning Evolutionary Developmental Biology

To examine how well biology majors have achieved the necessary foundation in evolution, numerous studies have examined how students learn natural selection. However, no studies to date have examined how students learn developmental aspects of evolution (evo-devo). Although evo-devo plays an increasing role in undergraduate biology curricula, we find that instruction often addresses development cursorily, with most of the treatment embedded within instruction on evolution. Based on results of surveys and interviews with students, we suggest that teaching core concepts (CCs) within a framework that integrates supporting concepts (SCs) from both evolutionary and developmental biology can improve evo-devo instruction. We articulate CCs, SCs, and foundational concepts (FCs) that provide an integrative framework to help students master evo-devo concepts and to help educators address specific conceptual difficulties their students have with evo-devo. We then identify the difficulties that undergraduates have with these concepts. Most of these difficulties are of two types: those that are ubiquitous among students in all areas of biology and those that stem from an inadequate understanding of FCs from developmental, cell, and molecular biology.