Internet use in the contemporary media environment

Although a significant amount of research has focused on traditional media choice and use, and even on some ‘new’ media, these studies have either neglected the Internet and World Wide Web or were conducted prior to their recent popularity. This study offers a novel exploration of individuals' use of three Internet functions (information retrieval, information giving, and conversation capabilities) in the context of the use of other communication media. Data from 684 individuals demonstrate that the Internet is a multidimensional technology used in a manner similar to other, more traditional media. Specifically, conversation features of the Internet align with mediated interpersonal technologies (the telephone and electronic mail), whereas the Internet's information‐retrieval and information‐giving features are used in ways similar to mass media channels (newspapers, television, and books and magazines). In addition, needs fulfilled by these channels cluster in ways consistent with past research, regardless of the technologies employed to meet them.     

Effects of Playing Videogames on Children's Aggressive and Other Behaviors1

Noting the pervasiveness of videogames in American culture, the authors set out to examine the effects that playing videogames has on children. Thirty-one children were matched on sex, randomly assigned to play either a violent (karate) videogame or a nonviolent (jungle vine swinging) videogame, and then observed during free play. The main results were that the children who had played the jungle swing videogame later played more with a jungle swing toy and that the children who played the violent videogame later showed more aggression. The authors interpreted the findings as an indication that young children who play videogames later tend to act similarly to how their videogame character acted.     

In Vivo Hippocampal Acetylcholine Release During Exposure to Acute Stress

Hippocampal extracellular acetylcholine (ACh) and choline levels were evaluated using in vivo microdialysis in male Fischer 344 rats before, during, and following an 80-min exposure to two different stress conditions. Measurements were taken in rats restrained and immersed in a water bath containing either 37 degreesC (normothermic-restraint) or 20 degreesC (cold-restraint) water. Results were compared to normothermic-freely-moving rats. Cold-restrained rats displayed decreased ACh levels during cold exposure relative to both normothermic-restrained and normothermic-freely-moving rats. By the end of the cold exposure period and following removal from cold, ACh levels had returned to near-baseline values. Normothermic-restrained rats had levels similar to those of normothermic-freely-moving rats, except for a marked increase in ACh following removal from restraint. Cold-restrained rats displayed a gradual elevation in choline levels during cold stress, followed by a gradual decline after stress termination, whereas both normothermic-restrained and normothermic-freely-moving rats displayed gradual decreases during the microdialysis session. These findings demonstrate that central cholinergic neurotransmission can be altered by the application of, and removal from, acute stressors. In addition, the results suggest a possible relationship between the magnitudes of both the stressor and its cholinergic consequences.     

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.     

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.

     

Aging and effect of predictability on reality monitoring

This study compared the direction of source confusions and the effect of predictability on reality monitoring for internally generated information and externally derived information in younger (mean age 19-25) and older (mean age 70-85) adults. Participants were invited to listen to the conclusions of simple stories or to generate and imagine them. Conclusions could be either highly predictable (Experiment 1) or unpredictable (Experiment 2). The change in predictability produced changes in the direction of source confusions only in older adults. When a story ended in a predictable way, older adults attributed to imagination conclusions that were actually perceived, whereas the pattern of confusions tended to reverse with unpredictable stories.