Depletion of cortical norepinephrine in rats by 6-hydroxydopamine does not impair performance of a delayed-nonmatching-to-sample task.

Rats were trained on a spatial delayed-nonmatching-to-sample (DNMTS) task, matched for performance, and randomly assigned to treatment with dorsal noradrenergic bundle injections of either 6-hydroxydopamine, to deplete cortical norepinephrine (NE), or vehicle, to control for the effects of surgery. After recovery, there were no significant differences between the groups when retrained on the DNMTS task at retention intervals (RIs) from 0.1 to 15.0 sec. Furthermore, no differences were observed when rats were trained at a 6.0-sec RI filled with distracting stimuli or when dummy information runs were added to increase proactive interference. These results demonstrate that depletion of cortical NE cannot account for the DNMTS performance deficits observed in rats recovered from pyrithiamine-induced thiamine deficiency (R. L. Knoth and R. G. Mair, 1991; J. K. Robinson and Mair, 1992). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Responses to depression and their effects on the duration of depressive episodes.

Proposes that the ways people respond to their own symptoms of depression influence the duration of these symptoms. People who engage in ruminative responses to depression, focusing on their symptoms and the possible causes and consequences of their symptoms, will show longer depression than people who take action to distract themselves from their symptoms. Ruminative responses prolong depression because they allow the depressed mood to negatively bias thinking and interfere with instrumental behavior and problem-solving. Laboratory and field studies directly testing this theory have supported its predictions. The author discusses how response styles can explain the greater likelihood of depression in women than men, then integrates this response styles theory with studies of coping with discrete events. The response style theory is compared to other theories of the duration of depression. Finally, suggestions are made that may help a depressed person to stop engaging in ruminative responses and on how response style for depression may develop. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Individual differences in extended practice functions and solution strategies for basic addition facts.

Practice on addition basic facts and changes in solution strategies were examined in 3rd- and 4th-grade students, practicing over 3 months. Response latencies decreased, indicating positive practice effects. Each of 3 student groups demonstrated different solution–strategy mixtures. Different mixtures led to different practice effects, indexed by shifts to more efficient counting strategies and more direct retrieval. Expectations about effects of practice and instructional strategies for optimizing practice must be sensitive to a child's actual strategy pattern. Most students had decreasing latency practice functions. However, quantitative functions fit to the practice session data indicated a high proportion of cases where the latency pattern over sessions was nonmonotonic. Trends over a small number of practice sessions may be inadequate for decisions about the utility of further practice, because such data may poorly represent long-term, cumulative effects on modifying strategy usage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Does the medium matter? The interaction of task type and technology on group performance and member reactions.

Investigated the hypothesis that as group tasks pose greater requirements for member interdependence, communication media that transmit more social context cues will foster group performance and satisfaction. 72 3-person groups of undergraduates worked in either computer-mediated or face-to-face meetings on 3 tasks with increasing levels of interdependence: an idea-generation task, an intellective task, and a judgment task. Results showed few differences between computer-mediated and face-to-face groups in the quality of the work completed but large differences in productivity favoring face-to-face groups. Analysis of productivity and of members' reactions supported the predicted interaction of tasks and media, with greater discrepancies between media conditions for tasks requiring higher levels of coordination. Results are discussed in terms of the implications of using computer-mediated communication systems for group work. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Hypothermic vocalizations of rat pups (Rattus norvegicus) and direct maternal search behavior.

Emissions of ultrasonic vocalizations (USVs) by rat pups (Rattus norvegicus) during hypothermia have consequences for recovery and warming. The effects on dam behavior of USVs emitted by 3- to 11-day-old pups during hypothermia at rectal temperatures between 18 and 22°C was investigated Rat dams were tested in a Y maze with the home cage as a start box. Dams were given, in one condition, a choice between a hypothermic pup emitting USVs or a hypothermic, silent (anesthetized) pup and, in the other, a choice between 2 hypothermic, silent pups. Although differing in some acoustic properties from normal isolation calls, USVs emitted by hypothermic pups both elicited maternal search behavior and acted as directional cues for dams, in comparisons with control dams exposed only to silent pups. Thus USVs of pups recovering from extreme hypothermia have communicative as well as physiological significance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Roles of living arrangements and grandmother social support in adolescent mothering and infant attachment.

Examined the roles of social support from adolescents' mothers and living arrangements in 197 adolescent mother–infant pairs. Major observational measures were teaching interactions, Home Observation for Measurement of the Environment (HOME) scores, and infant attachment security. Adolescents living with neither mothers nor partners had better teaching interactions but lower HOME scores compared with those living with mothers. High mother support was associated with more secure infant attachment only for those adolescents living with partners. When mother support was low, adolescents living alone had more secure infants than adolescents living with partners. Although parenting scores were related to differences in demographics and personal resources (intelligence and social skills), these did not appear to be responsible for the major findings. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The Structure of Working Memory From 4 to 15 Years of Age.

The structure of working memory and its development across the childhood years were investigated in children 4-15 years of age. The children were given multiple assessments of each component of the A. D. Baddeley and G. Hitch (1974) working memory model. Broadly similar linear functions characterized performance on all measures as a function of age. From 6 years onward, a model consisting of 3 distinct but correlated factors corresponding to the working memory model provided a good fit to the data. The results indicate that the basic modular structure of working memory is present from 6 years of age and possibly earlier, with each component undergoing sizable expansion in functional capacity throughout the early and middle school years to adolescence. (PsycINFO Database Record (c) 2010 APA, all rights reserved)