Embedding instructive feedback into teacher-student interactions during independent seat work

The effects of embedding a constant time delay procedure into an independent seat work activity and using instructive feedback were evaluated in this study. Seven students with mild disabilities participated in the study that occurred in their special education classroom. A multiple probe design across sets of target behaviors was used, and students' responses to instructive feedback stimuli were evaluated during each probe condition. The procedures were implemented with a high degree of fidelity, and the results indicate that (a) the students acquired the target behaviors taught with the constant time delay procedure that was embedded into independent seat work, and (b) the students acquired some but not all of the responses to the instructive feedback stimuli. These findings are discussed in terms of using instructive feedback in classrooms and future research on instructive feedback.     

Lightness contrast in CRT and paper-and-illuminant displays

The increased use of CRT monitors for displaying and controlling stimuli in studies of surface color poses problems of comparability with data obtained with traditional paper-and-illuminant methods. A review of comparable studies using the two methodologies revealed that CRT studies tend to report larger contrast effects. To investigate factors that may be responsible for this difference, simultaneous lightness contrast was measured using both CRT and paper-and-illuminant presentations. The spatial distribution of luminance in the whole field of view and the visual angles subtended by the displays were controlled. The CRT presentation yielded contrast effects twice as big as those measured for a paper surface in a homogeneously illuminated room. However, a paper display under Gelb lighting yielded almost exactly the same effect size as that measured in the CRT presentation. These results demonstrate that contrast effects in both modes of presentation are affected by the spatial distribution of luminance beyond the basic experimental stimuli.     

Deficits in prospective memory following damage to the medial subdivision of the mediodorsal thalamic nucleus

Identifying the neurocognitive mechanisms that lead individuals remembering to execute an intention at the right moment (prospective memory, PM) and how such mechanisms are influenced by the features of that intention is a fundamental theoretical challenge. In particular, the functional contribution of subcortical regions to PM is still unknown. This study was aimed at investigating the role of the medial subdivision of the mediodorsal thalamic nucleus (mMDT) in PM, with particular focus on the processes that are mediated by the projections from/to this structure. We analysed the performance of a patient (OG) with a right-sided lesion involving the mMDT in a series of PM tasks that varied for focality (i.e., overlapping of processes for the PM and ongoing tasks) and emotional valence of the stimuli, comparing the patient's performance with that of a control group. We found that the mMDT damage led to deficits in PM that were modulated by focality and emotional valence. OG indeed showed: a greater cost in the ongoing performance when a non-focal PM task was added; a slowing down in retrieving the intentions, in particular when these were associated with focal PM cues; an abnormal performance in the task with positive PM cues. Our findings provide evidence of a contribution of mMDT to PM and suggest a modulation of prefrontal-dependent strategic monitoring and a possible interaction with the limbic structures in the integration of emotion and PM processes. They also give support to the still controversial idea that connections with the perirhinal cortex mediate familiarity-based recognition.     

Navigating in a challenging semiarid environment: the use of a route-based mental map by a small-bodied neotropical primate

To increase efficiency in the search for resources, many animals rely on their spatial abilities. Specifically, primates have been reported to use mostly topological and rarely Euclidean maps when navigating in large-scale space. Here, we aimed to investigate if the navigation of wild common marmosets inhabiting a semiarid environment is consistent with a topological representation and how environmental factors affect navigation. We collected 497 h of direct behavioral and GPS information on a group of marmosets using a 2-min instantaneous focal animal sampling technique. We found that our study group reused not only long-route segments (mean of 1007 m) but entire daily routes, a pattern that is not commonly seen in primates. The most frequently reused route segments were the ones closer to feeding sites, distant to resting sites, and in areas sparse in tree vegetation. We also identified a total of 56 clustered direction change points indicating that the group modified their direction of travel. These changes in direction were influenced by their close proximity to resting and feeding sites. Despite our small sample size, the obtained results are important and consistent with the contention that common marmosets navigate using a topological map that seems to benefit these animals in response to the exploitation of clustered exudate trees. Based on our findings, we hypothesize that the Caatinga landscape imposes physical restrictions in our group’s navigation such as gaps in vegetation, small trees and xerophytic plants. This study, based on preliminary evidence, raises the question of whether navigation patterns are an intrinsic characteristic of a species or are ecologically dependent and change according to the environment.