Self-control in the monkeymacaca fascicularis

Two experiments tested two cynomolgus monkeys’ self-control—choice of a longer, more delayed reinforcer over a shorter, less delayed reinforcer. In Experiment 1, subjects exhibited significant selfcontrol in a procedure in which reinforcer amounts and delays were held constant throughout a condition. In Experiment 2, subjects exhibited significantly greater sensitivity to variation in reinforcer amount than to variation in reinforcer delay in a procedure in which the reinforcer delay associated with the self-control alternative was adjusted until each macaque was indifferent between the two alternatives. Both experiments indicated that, in laboratory paradigms in which humans show self-control and pigeons and rats show impulsiveness, macaques show self-control. These results are inconsistent with the hypothesis that species differences in self-control are a function of language ability or of specific types of prior training. The results are consistent with the hypothesis that species differences in self-control are related to the ratio of brain size to body weight (a possible indicator of general cognitive ability) or to shared phylogeny.     

Accumbens D2: Raters of the Loss Outcome

Zalocusky et al. (Nature 531:642–646, 2016) recently showed that activity in D2R+ cells in the nucleus accumbens is associated with loss sensitivity to prior outcomes and reduced subsequent risky choice, and that optogenetic stimulation of these cells decreased risky choices in risk-prone rats. While their findings are important for understanding trait-level risk-taking, future research should aim to examine the neuronal mechanisms of a broader range of facets of gain and loss processing with respect to different potential reference points.     

Development of the process conception of function

Our goal in this paper is to make two points. First, college students, even those who have taken a fair number of mathematics courses, do not have much of an understanding of the function concept; and second, an epistemological theory we have been developing points to an instructional treatment, using computers, that results in substantial improvements for many students. They seem to develop a process conception of function and are able to use it to do mathematics. After an introductory section we outline, in Section 2, our theoretical epistemology in general and indicate how it applies to the function concept in particular. In Sections 3, 4, and 5 we provide specific details on this study and describe the development of the function concept that appeared to take place in the students that we are considering. In Section 6 we interpret the results and draw some conclusions.     

A validation of the Dyslexia Adult Screening Test (DAST) in a post‐secondary population

In Ontario, Canada, there is a demand for psychometrically robust screening tools capable of efficiently identifying students with specific learning disabilities (SLD), such as dyslexia. The present study investigated the ability of the Dyslexia Adult Screening Test (DAST) to discriminate between 117 post‐secondary students with carefully diagnosed SLDs and 121 comparison students. Results indicated that the DAST correctly identified only 74% of the students with SLDs as ‘highly at risk’ for dyslexia. Although employing the cutoff for ‘mildly at risk’ correctly identified 85% of the students with SLDs, this also increased the percentage of students with no major history of learning problems identified as ‘at risk’ for dyslexia from 16% to 26%. These findings suggest that the DAST in its present form is limited in its ability to screen for SLDs. Implications for future research are discussed.     

The Structure and Substance of Teachers’ Opportunities to Learn about Teacher Evaluation Reform: Promise or Pitfall for Equity?

Despite growing momentum to overhaul teacher evaluation policies and practices, scant research examines how educators at the street level of such reform—principals and teachers—make sense of them, and almost no research examines the implications of current evaluation reforms for equity. This article provides findings based on a study of 14 districts implementing a new teacher evaluation policy in Connecticut. It focuses on how principals shaped teachers’ opportunities to learn about the new policy. We find that the majority of teachers’ opportunities to learn were formal and in whole group or one-on-one formats. We find important differences in the quantity and quality of learning opportunities at the district level, with districts serving greater shares of low-income students, students of color, and English language learners generally offering teachers fewer and lower quality opportunities to learn about the new reform than their counterparts. As such, this article builds on prior research illustrating the potential of new evaluation systems to exacerbate inequities and raises important cautions regarding the extent to which the unprecedented teacher evaluation reforms (currently underway) may exacerbate inequities among school districts.     

Discriminating between reward-produced memories: Effects of differences in reward magnitude

The greater the dissimilarity between exteroceptive stimuli, the easier it is to discriminate between them. To determine whether a similar relationship holds for memories produced by reward events, rats in three runway investigations received trials in pairs, the number of food pellets (0.045 g) occurring on Trial 1 indicating whether reward or nonreward would occur on Trial 2. In each investigation, discriminative responding on Trial 2 was better the larger the difference in reward magnitude on Trial 1. This finding was obtained under a wide variety of conditions: for example, when the larger of two reward magnitudes on Trial 1 signaled nonreward on Trial 2 (Experiment 1, 10 vs. 2 pellets); when the smaller of two reward magnitudes on Trial 1 signaled nonreward on Trial 2 (Experiment 2, 10 vs. 2 pellets); and when the same magnitude of reward on Trial 1 signaled nonreward on Trial 2 (Experiment 3, either 5 pellets or 0 pellets). The findings obtained here indicate that the greater the dissimilarity between reward magnitudes, the greater the dissimilarity between the memories they produced and, thus, the easier it is to discriminate between them. It is suggested that the present results may provide a basis for understanding findings obtained in other instrumental learning investigations in which reward magnitude is varied.     

Gardnerella vaginalis infection and sexual contact in female children

Gardnerella vaginalis (GV) infection has been reported as being acquired via sexual contact in adults and as an indicator of sexual contact in female children (DeJong, 1985). The purpose of this study was to determine if GV infection was more commonly found in 191 female children who gave a history of sexual contact and/or were infected with Neisseria gonorrhoeae (GC) or Chlamydia trachomatis (CT) (Group 1), compared with 144 female children evaluated for possible sexual abuse and found to have no such history or infection with GC or CT (Group 2), or 31 female children (friends of the authors) without such a history or GC or CT infection (Group 3). Vaginal GV was found in 5.3% of Group 1, 4.9% of Group 2 and 6.4% of Group 3 (p > .05). Also, vaginal GV infection was not related to the type of sexual contact or race, but did increase with age in white female children. Because vaginal GV infection is not more commonly found in children with a history of sexual contact than those without such a history, the finding of GV in a vaginal culture in an individual case would not be a reliable marker of sexual contact. Routine culturing for GV is not recommended as part of a sexual abuse workup.