Anticipatory contrast as a measure of time horizons in the rat: Some methodological determinants

In three experiments, the time horizon over which the rat evaluates alternative feeding sources was investigated. The time horizon was measured by the suppression of intake of one incentive (a 0.15% saccharin solution) when a preferred alternative incentive (a 32% sucrose solution) was available but delayed. In Experiment 1, we found a direct function between the amount of saccharin intake and the delay time before access to 32% sucrose. Compared with intake for a saccharin-only control, saccharin intake was suppressed before 4-min and 16-min sucrose delays, but not before a 32-min delay. Because previous work (Flaherty & Checke, 1982) had reported suppression before a delay of nearly 32 min, in the subsequent experiments we examined factors that might account for this difference. In Experiment 2, we found that saccharin intake was suppressed before a 32-min delay interval when saccharin and sucrose solutions were presented in a bright-novel test environment but not when the same solutions were presented in the home cage. In Experiment 3, we found that the time between testing and subsequent postsession feeding could also affect the suppression of saccharin intake. Saccharin intake was suppressed when access to 32% sucrose was delayed by 32 min and the test situation was followed by immediate postsession feeding, but not when postsession feeding was delayed by 90 min. These results thus extend estimates of the rat’s time horizon to at least 32 min, but indicate that the effective time horizon can vary, depending on the test situation.     

Four dialogues and metalogues about the nature of science

We analyse and explore, in the form of dialogues and metalogues questions about the dialogic nature of beliefs and students belief talk about the nature of science and scientific knowledge. Following recent advances in discursive psychology, this study focuses not on students' claims but on the discursive resources and dialogical practices that support the particular claims they make. We argue that students' discourse is better understood as a textual bricolage that is sensitive to conversational context, common sense, interpretive repertoires, and textual resources available in the conversational situation. Our text is reflexive as it embodies the discursive construction of knowledge and undercuts any claims to authoritative knowledge. The very conception of “belief” is itself an expression or construction from within the mundane idiom.... We learn to use “belief” in conditions when the “objective facts” are unknown or problematic and we want to indicate the tenuous character of our claim.... The notion of “real world” or “objective reality” is embedded in an extensive, pervasive language game which includes as an intelligible move or possibility the use of the very concept of “belief” itself. (Pollner, 1987, p. 21)     

Exploring features for the automatic identification of user goals in web search

Queries submitted to search engines can be classified according to the user goals into three distinct categories: navigational, informational, and transactional. Such classification may be useful, for instance, as additional information for advertisement selection algorithms and for search engine ranking functions, among other possible applications. This paper presents a study about the impact of using several features extracted from the document collection and query logs on the task of automatically identifying the users’ goals behind their queries. We propose the use of new features not previously reported in literature and study their impact on the quality of the query classification task. Further, we study the impact of each feature on different web collections, showing that the choice of the best set of features may change according to the target collection.     

The relative effects of university success courses and individualized interventions for students with learning disabilities

Little is known about the relative effects of post‐secondary learning services for students with learning disabilities. We compared outcomes for students with learning disabilities who selected to: (1) take an academic learning success course (course‐intervention), (2) have regular individual interventions (high‐intervention) or (3) use services only as needed (low‐intervention). Pre‐ and post‐test comparisons revealed improvements in academic self‐efficacy and academic resourcefulness for students in the course‐ and high‐intervention groups. The course‐intervention group also showed decreases in their failure attributions to bad luck and increases in their general repertoire of learned resourcefulness skills in comparison to the high‐intervention group and had significantly higher year‐end GPAs in comparison to the low‐intervention group. Here we find positive outcomes for students with learning disabilities taking a course that teaches post‐secondary learning and academic skills.     

Using critical literacy to explore genetics and its ethical, legal, and social issues with in-service secondary teachers

The described interdisciplinary course helped a mixed population of in-service secondary English and biology teacher-participants increase their genetics content knowledge and awareness of Ethical, Legal, and Social Implications (ELSI) that arose from discoveries and practices associated with the Human Genome Project. This was accomplished by applying a critical literacy approach that allows people develop cognitive skills such that they are able to "read the world" (Wink, 2004). The approach is one that permits readers to go beyond the literal text to examine what is present as well as what is missing as it relates to issues of equity and fairness. Becoming critically literate enabled these teacher-participants to challenge the subtle attitudes, values, and beliefs conveyed by a range of written and oral texts. The teacher-participants in this course improved their critical literacy skills by actively reading, critically writing about, and using evidence to support their conclusions about issues arising from advances in human genetics. A biologist, a linguist, and an educator collaboratively designed and taught the course. The personalized focus on the integration of thoughtful reading and writing in this class enhanced the teacher-participants' (n = 16) professional and intellectual development and will potentially improve learning in their biology and English classrooms in the future.     

History effects on induced and operant variability

Two experiments evaluated history effects on induced and operant variability. College students typed three-digit sequences on a computer keyboard. Sequence variability was induced (by no reinforcement or variation- independent reinforcement) or reinforced (by variation- or repetition-dependent reinforcement). Conditions with induced and operant variability were presented according to a reverse between-groups design. In Experiment 1, we examined transitions from the variation or repetition contingencies to no reinforcement, and vice versa. In Experiment 2, the variation or repetition contingencies were followed or preceded by variation-independent reinforcement. The results showed that (1) a history of no reinforcement impaired operant variability learning; (2) induced variability levels were higher and lower after a history of reinforcement for variation and repetition, respectively; (3) repetition was more easily disrupted by no reinforcement and independent reinforcement than was variation; and (4) response variability and stability were a function of past and current reinforcement conditions. These results indicate that reinforcement history influences both induced and operant variability levels.     

Trolling in online communities: A practice-based theoretical perspective

The literature on trolling has viewed trolling as discrete instances of transgression undertaken by antagonistic individuals. We identify three main issues with current theorizations: diffuse definitions of “trolling,” blurred boundaries between trolling and other online anti-social behaviors, and the context dependency of trolling. To address these unresolved issues, we adopt a practice-based theoretical approach. Informed by this approach, we analyze trolling behaviors not as products of individuals' attitudes, values, and decisions, but rather as behaviors embedded within and occurring as part of social practices. Specifically, we conduct a practice-based theoretical analysis in a multi-site exploratory study involving online archival research and in-depth interviews with online community members. Based on this analysis, we propose that trolling be conceived as a constellation of three social practices: learning, assimilating, and transgressing. Also, we find that practices of trolling transgression can have a dual pro-social and anti-social impact in online communities.     

Effects of an unsupervised pedometer-based physical activity program on daily steps of adults with moderate to severe asthma: a randomized controlled trial

Supervised exercise has shown benefits for subjects with asthma, but little is known about the effectiveness of unsupervised physical activity on this population. We investigated the effects of a 12-week unsupervised pedometer-based physical activity program on daily steps and on clinical and psychological parameters of adults with asthma. Clinically stable adults with moderate to severe asthma were encouraged to take daily 30-minute walks and were randomized to pedometer and control groups. The pedometer group received pedometers and individualized daily step targets. Changes in daily steps (average of steps taken during six consecutive days), six-minute walk test (6MWT), health-related quality of life, asthma control and anxiety and depression levels were assessed 12 weeks after intervention and 24–28 weeks after randomization. Thirty-seven participants were recruited and 30 completed the intervention. At 12 weeks, the groups differed significantly in daily steps (adjusted average difference, 2488 steps; 95% confidence interval [CI], 803 to 4172; p = 0.005) and in the 6MWT (adjusted average difference, 21.9 m; 95% CI, 6.6 to 37.3; p = 0.006). These differences were not significant 24–28 weeks after randomization. The program was effective in increasing daily steps of adults with moderate to severe asthma 12 weeks after intervention.