The influences of methylphenidate on heart rate and behavioral measures of attention in hyperactive children.

Reaction-time performance and heart-rate responses associated with attention were used to assess the hyperactive child's attentional deficit and his response to methylphenidate. Attentional deficits shown by long response latencies were reflected in heart-rate responses theoretically incompatible with sustained attention. Subjects exhibiting the greatest attentional deficit displayed the most favorable response to methylphenidate in both reaction-time performance and physiological measures. However, subjects who showed the greatest improvement in social behavior were those who showed the least improvement in reaction-time performance.     

Preference between fixed-interval and variable-interval schedules of reinforcement: Separate roles of temporal scaling and predictability

Pigeons’ preference between fixed-interval and variable-interval schedules was examined using a concurrent-chains procedure. Responses to two concurrently available keys in the initial links of the concurrent chains occasionally produced terminal links where further responses were reinforced under either a fixed- or variable-interval schedule. In previous studies, preferences for the variable schedule with such a procedure have been interpreted as reflecting atemporal scaling process that heavily weights the shorter intervals in the variable schedule. The present experiment examined whetherpredictability, i.e., the presence of external stimuli correlated with the reinforcement interval, might also influence preference in such situations. When the two intervals in a variable schedule were made predictable by being associated with different key colors, preference for that schedule increased. This increase was reliable but small in magnitude and transient when initial-link responses only occasionally produced terminal links; it was large in magnitude when only one response in the initial link was required to produce the appropriate terminal-link schedule. The results suggest that preference between fixed and variable schedules may be influenced both by temporal scaling and to a lesser extent by predictability of the reinforcement intervals.     

The Effect of Stereoscopic Augmented Reality Visualization on Learning Anatomy and the Modifying Effect of Visual-Spatial Abilities: A Double-Center Randomized Controlled Trial

Monoscopically projected three-dimensional (3D) visualization technology may have significant disadvantages for students with lower visual-spatial abilities despite its overall effectiveness in teaching anatomy. Previous research suggests that stereopsis may facilitate a better comprehension of anatomical knowledge. This study evaluated the educational effectiveness of stereoscopic augmented reality (AR) visualization and the modifying effect of visual-spatial abilities on learning. In a double-center randomized controlled trial, first- and second-year (bio)medical undergraduates studied lower limb anatomy with stereoscopic 3D AR model (n = 20), monoscopic 3D desktop model (n = 20), or two-dimensional (2D) anatomical atlas (n = 18). Visual-spatial abilities were tested with Mental Rotation Test (MRT), Paper Folding Test (PFT), and Mechanical Reasoning (MR) Test. Anatomical knowledge was assessed by the validated 30-item paper posttest. The overall posttest scores in the stereoscopic 3D AR group (47.8%) were similar to those in the monoscopic 3D desktop group (38.5%; P = 0.240) and the 2D anatomical atlas group (50.9%; P = 1.00). When stratified by visual-spatial abilities test scores, students with lower MRT scores achieved higher posttest scores in the stereoscopic 3D AR group (49.2%) as compared to the monoscopic 3D desktop group (33.4%; P = 0.015) and similar to the scores in the 2D group (46.4%; P = 0.99). Participants with higher MRT scores performed equally well in all conditions. It is instrumental to consider an aptitude–treatment interaction caused by visual-spatial abilities when designing research into 3D learning. Further research is needed to identify contributing features and the most effective way of introducing this technology into current educational programs.     

Getting at the Mathematics: Sara’s Journal

In this paper, we discuss issues in planning and conducting research into mathematics learning. We emphasize two central themes: (a) the learners mathematics (especially the issues and ideas, in given problem situations, that learners choose to think about and to present) and (b) the kinds of knowledge that learners may be building (including their ideas about what mathematics is, and how people do, learn, use, communicate and understand it). While the first theme is at least partly mathematical, the second interweaves cognition and epistemology. Anchored in student data from an extended classroom teaching experiment in the mathematics of change, we focus on key choices needed to build narratives to help researchers capture, in detail, how students engage with mathematics in extended problem explorations.     

The role of number and spacing of CS-US pairings in conditioned suppression

In four studies, with rats as Ss. acquisition and. where appropriate, extinction trials were presented against a baseline of ongoing licking. At shock intensities of 0.1. 0.5. 1.0, or 2.0 mA, acquisition performance was a function of number of CS-US pairings: spacing of trials (one or two per day) did not affect acquisition performance. Resistance to extinction could be predicted from terminal acquisition performance and reached a maximum after three CS-US pairings.