The contagious impact of playing violent video games on aggression: Longitudinal evidence

Meta-analyses have shown that violent video game play increases aggression in the player. The present research suggests that violent video game play also affects individuals with whom the player is connected. A longitudinal study (N = 980) asked participants to report on their amount of violent video game play and level of aggression as well as how they perceive their friends and examined the association between the participant's aggression and their friends’ amount of violent video game play. As hypothesized, friends’ amount of violent video game play at Time 1 was associated with the participant's aggression at Time 2 even when controlling for the impact of the participant's aggression at Time 1. Mediation analyses showed that friends’ aggression at Time 1 accounted for the impact of friends’ amount of violent video game play at Time 1 on the participant's aggression at Time 2. These findings suggest that increased aggression in video game players has an impact on the player's social network.     

Brain responses reveal that infants' face discrimination is guided by statistical learning from distributional information

Infants' perception of faces becomes attuned to the environment during the first year of life. However, the mechanisms that underpin perceptual narrowing for faces are only poorly understood. Considering the developmental similarities seen in perceptual narrowing for faces and speech and the role that statistical learning has been shown to play for speech, the current study examined whether and how learning from distributional information impacts face identity discrimination. We familiarized 6.5‐month‐old infants with exemplars of female faces taken from a morphed continuum going from one identity to another. Using event‐related brain potentials (ERPs), we show that only infants who were familiarized with a bimodal frequency distribution, but not infants familiarized with a unimodal frequency distribution, discriminated between identities. These results are the first to demonstrate the influence of probabilistic information on infants' face identity discrimination, suggesting that statistical learning contributes to perceptual attunement for both faces and language.     

Study of Human Biochemical Parameters During and After Ramadan

Ramadan fasting is obligatory for Muslims each year. They abstain from drinking, eating and intimate relationship between dawn and dusk during this month. Dietary restriction during Ramadan has various biochemical and physiological effects. It is shown to decrease the body weight, glucose and lipid profile. This study aims to analyze the changes in body weight, glucose and lipid profile during Ramadan in physiotherapy students in Pakistan. The study was conducted during June–July 2013 (Hijri year 1434). There were 80 students (50 males and 30 females) recruited in the experiment. They all were healthy adults between the age group of 18–24 (mean age 20.5) years. All subjects underwent a general physical examination and interview, and non-healthy subjects were excluded. On statistical analysis, quantitative data were expressed in terms of mean ± SD and a p value of ≤0.05 was believed statically significant. Paired t test was used to compare the variables. There was a little reduction in body weight (62.7 ± 8.8 vs. 62.3 ± 9.0; p value = 0.009) but a significant decline in glucose level (72.6 ± 12.5 vs. 57.9 ± 10.7; p value = 0.000), low-density lipoprotein level (2.9 ± 0.3 vs. 2.5 ± 0.3; p value = 0.000), total cholesterol (4.6 ± 0.4 vs. 4.2 ± 0.5; p value = 0.000) and triglycerides (1.4 ± 0.5 vs. 1.2 ± 0.5; p value = 0.000) was observed. Moreover, there was some reduction in high-density lipoprotein cholesterol level (1.2 ± 0.3 vs. 1.1 ± 0.3; p value = 0.045). This study shows that Ramadan fasting, a religious obligation for purification of body and soul, resulted in reduced body weight and a positive effect on glucose level and lipid profile.     

Pseudocontingencies in Consumer Choice: Preference for Prevalent Product Categories Decreases with Decreasing Set Quality

Building on theorizing about contingency inferences, the present research deals with the impact of product category prevalence on consumer choice. We argue that a category's prevalence in the choice set can signal high quality, but the validity depends on the aggregate quality of the choice set. With ever more low‐quality products in the set, high prevalence should increasingly signal poor rather than high quality. When choosing from a poor‐quality set, choices should thus favor products from the rare category. In four experiments, we show that poor‐quality sets increase the proportion of consumers choosing products from a rare category. Furthermore, we show that these effects increase when base rates of a category and quality become more extreme. Finally, Experiment 4 shows that contingency inferences partly mediate the effect of set quality on choice. The results extend previous research on contingency inferences, indicating the adaptive use of base‐rate information in consumer decision making. Copyright © 2017 John Wiley & Sons, Ltd.     

Hippocampal tauopathy in tau transgenic mice coincides with impaired hippocampus-dependent learning and memory, and attenuated late-phase long-term depression of synaptic transmission

We evaluated various forms of hippocampus-dependent learning and memory, and hippocampal synaptic plasticity in THY-Tau22 transgenic mice, a murine tauopathy model that expresses double-mutated 4-repeat human tau, and shows neuropathological tau hyperphosphorylation and aggregation throughout the brain. Focussing on hippocampus, immunohistochemical studies in aged THY-Tau22 mice revealed prominent hyper- and abnormal phosphorylation of tau in CA1 region, and an increase in glial fibrillary acidic protein (GFAP) in hippocampus, but without signs of neuronal loss. These mice displayed spatial, social, and contextual learning and memory defects that could not be reduced to subtle neuromotor disability. The behavioral defects coincided with changes in hippocampal synaptic functioning and plasticity as measured in paired-pulse and novel long-term depression protocols. These results indicate that hippocampal tauopathy without neuronal cell loss can impair neural and behavioral plasticity, and further show that transgenic mice, such as the THY-Tau22 strain, might be useful for preclinical research on tauopathy pathogenesis and possible treatment.     

The importance of response type to the relationship between temporal order and numerical magnitude

Time, number, and space may be represented in the brain by a common set of cognitive/neural mechanisms. In support of this conjecture, Schwarz and Eiselt (Journal of Experimental Psychology: Human Perception and Performance, 35, 989-1004, 2009) found that numerically smaller digits were perceived to occur earlier than larger digits, and they concluded that this difference reflected faster processing of smaller numbers. This difference, however, could have been related to a response bias, whereby participants map responses of "which first" onto the "first" number along the mental number line. In Experiment 1, participants made temporal order judgements between digits presented to the left or to the right. The point of subjective simultaneity was shifted so that the 9 had to be presented before the 2 in order for simultaneity to be perceived. This difference could reflect either faster processing of the 2 or a response bias. Experiments 2a and 2b eliminated response biases by using simultaneity judgements, which have no logical stimulus mapping. Both of the latter experiments established that the 2 was not processed faster than the 9. Although the present results relate specifically to numerical magnitude and temporal order associations, they also have broader implications. Other studies have reported associations between dimensions such as size, duration, and number and have attributed these to parietal mechanisms. Such associations, however, may also be an artefact of response biases.     

The direction of hemispheric asymmetries for object categorization at different levels of abstraction depends on the task

In this study hemispheric asymmetries for categorizing objects at the basic versus subordinate level of abstraction were investigated. As predictions derived from different theoretical approaches are contradictory and experimental evidence is inconclusive in this regard, we conducted two categorization experiments, where we contrasted two experimental paradigms. In the first experiment, subjects had to verify whether a word and a laterally presented picture matched or not. In the second experiment, subjects had to identify laterally presented pictures of animals either at the basic or subordinate level by pressing a corresponding response key. Whereas the first experiment revealed an advantage of the left hemisphere (LH) for categorizing objects at the basic level and of the right hemisphere (RH) for categorizing at the subordinate level, just the opposite brain asymmetry was found in the second experiment. As the stimuli were identical in both experiments, hemispheric asymmetries seem to be strongly task dependent.     

Asymmetrical consequences of behavioral change through reward and punishment

Previous research (Greitemeyer & Weiner, 2003 ) has demonstrated that compliance, because of an anticipated reward is attributed more to the person than compliance because of an anticipated punishment. The present research extended these findings to an educational context. Three studies revealed that parents who ask their children to change inappropriate behaviors are more likely to ascribe their children's improvement to the child, if the child was promised a reward, rather than threatened, to receive a punishment if the child did not improve. Moreover, because a child's improved behavior is more likely to be ascribed to the child given a reward as compared to a punishment, parents expect that rewards (as opposed to punishments) are more likely to sustain improved behavior, when the incentive is no longer offered. Finally, participants report to be more likely to induce behavioral change through reward rather than punishment. Copyright © 2007 John Wiley & Sons, Ltd.