SGK protein kinase facilitates the expression of long-term potentiation in hippocampal neurons

Previous studies showed that the serum- and glucocorticoid-inducible kinase (sgk) gene plays an important role in long-term memory formation. The present study further examined the role of SGK in long-term potentiation (LTP). The dominant-negative mutant of sgk, SGKS422A, was used to inactivate SGK. Results revealed a time-dependent increase in SGK phosphorylation after tetanization with a significant effect observed 3 h and 5 h later. Transfection of SGKS422A impaired the expression, but not the induction, of LTP. Furthermore, the constitutively active sgk, SGKS422D, up-regulated postsynaptic density-95 expression in the hippocampus. These results together support the role of SGK in neuronal plasticity.     

Some properties of r equivalent: a simple effect size indicator

One version of r equivalent, calculated from Fisher's exact test p values and recommended for small samples, is considered "a more realistic . . . [and] a more accurate estimate of the population correlation than . . . the sample correlation, r sample" (R. Rosenthal & D. B. Rubin, 2003, p. 494). Small sample properties of r sample and of two effect size estimators (r equivalent* and r hybrid) that use r equivalent were examined: r sample is preferable to r equivalent* (defined as r equivalent used without restrictions) in terms of bias and mean squared error (MSE); r hybrid (defined as r equivalent only when r sample = 1.0) is generally preferable to r equivalent*, and preferable to r sample in terms of MSEs, except when population correlations are very large. Conditions favoring r sample over r equivalent* and r hybrid in meta-analyses are noted.     

Designing action games for appealing to buyers.

This study aims to identify design features for action games that would appeal to game-buyers, rather than game-players. Sixteen frequent-buyers of computer games identified 39 design features that appeal to buyers by contrasting different versions of Pacman games. Twenty-eight versions of Pacman were then evaluated in terms of the identified design features by 45 participants (27 male and 18 female college students). Qnet2000 neural network software was used to determine the relative importance of these design features. The results indicated that the top 10 most important design features could account for more than 50% of "perceived fun" among these 39 design features. The feature of avatar is important to game-buyers, yet not revealed in previous player-oriented studies. Moreover, six design factors underlying the 39 features were identified through factor analysis. These factors included "novelty and powerfulness," "appealing presentation," "interactivity," "challenging," "sense of control," and "rewarding," and could account for 54% of total variance. Among these six factors, appealing presentation has not been emphasized by player-oriented research. Implications of the findings were discussed.     

Sequence‐specific procedural learning deficits in children with specific language impairment

This study tested the procedural deficit hypothesis of specific language impairment (SLI) by comparing children's performance in two motor procedural learning tasks and an implicit verbal sequence learning task. Participants were 7‐ to 11‐year‐old children with SLI (n = 48), typically developing age‐matched children (n = 20) and younger typically developing children matched for receptive grammar (n = 28). In a serial reaction time task, the children with SLI performed at the same level as the grammar‐matched children, but poorer than age‐matched controls in learning motor sequences. When tested with a motor procedural learning task that did not involve learning sequential relationships between discrete elements (i.e. pursuit rotor), the children with SLI performed comparably with age‐matched children and better than younger grammar‐matched controls. In addition, poor implicit learning of word sequences in a verbal memory task (the Hebb effect) was found in the children with SLI. Together, these findings suggest that SLI might be characterized by deficits in learning sequence‐specific information, rather than generally weak procedural learning.     

Multiple contest experiences interact to influence each other’s effect on subsequent contest decisions in a mangrove killifish

Many animals modify behavioural decisions based on information they have previously acquired. Contest behaviour is often affected by previous contest experiences: individuals behave more and less aggressively after a victory and defeat, respectively (winner/loser effect). Individuals in the field sometimes encounter multiple competitors in quick succession, but whether these experiences interact to influence each other’s importance is unclear. We tested five hypotheses for experience interaction (no interaction, retroactive interference, proactive interaction, reinforcement and diminishing returns) using Kryptolebias marmoratus. Focal individuals were paired up with opponents having the same 1-month contest outcome (1 month before the experiment), as this difference in actual or perceived fighting ability has been shown to affect the fish’s response to new experiences. We gave the focal individual of a pair a winning or losing experience on day 1. Then both fish of the pair received the same winning, losing or no-contest experience on day 2. Then we organised fights between the two. The effect of a day-1 losing experience did depend on the fish’s actual or perceived fighting ability: one-month losers readily showed loser effects from the day-1 losing experience, irrespective of the day-2 experience (i.e. no interaction between day-1 and day-2 experiences). One-month winners, however, only showed loser effects from a day-1 losing experience when the day-2 experience was also a loss (i.e. reinforcement). Day-1 winning experiences did not interact with day-2 experiences in 1-month losers or winners. Therefore, multiple experiences sometimes reinforce each other, but how they combine to influence behaviour depends on an individual’s actual or perceived fighting ability.     

Predicting raters’ transparency judgments of English and Chinese morphological constituents using latent semantic analysis

The morphological constituents of English compounds (e.g., “butter” and “fly” for “butterfly”) and two-character Chinese compounds may differ in meaning from the whole word. Subjective differences and ambiguity of transparency make judgments difficult, and a computational alternative based on a general model might be a way to average across subjective differences. In the present study, we propose two approaches based on latent semantic analysis (Landauer & Dumais in Psychological Review 104:211–240, 1997): Model 1 compares the semantic similarity between a compound word and each of its constituents, and Model 2 derives the dominant meaning of a constituent from a clustering analysis of morphological family members (e.g., “butterfingers” or “buttermilk” for “butter”). The proposed models successfully predicted participants’ transparency ratings, and we recommend that experimenters use Model 1 for English compounds and Model 2 for Chinese compounds, on the basis of differences in raters’ morphological processing in the different writing systems. The dominance of lexical meaning, semantic transparency, and the average similarity between all pairs within a morphological family are provided, and practical applications for future studies are discussed.     

Differential Effects of Personality Traits and Environmental Predictors on Reproductive and Creative Imagination

The purpose of this study was twofold: (1) to analyze the effects of both personality and environmental variables on the imagination of video/film major university students; and (2) to test the mediator effect resulting from the variable of social climate. The results of this study supported both indicators of imaginative capabilities and environmental influences. The hypothesis of the study—that the variable of social climate mediates the effects of personality/environmental predictors and both types of imagination—was partially supported. The structural model also showed that most personality traits have direct effects on imagination, whereas most environmental predictors have indirect effects. Practical applications of this study were suggested, future inquiries were discussed, and limitations were acknowledged.     

Effects of Bilingualism and Trilingualism in L2 Production: Evidence from Errors and Self-Repairs in Early Balanced Bilingual and Trilingual Adults

Through analyzing response latencies, errors, and self-repairs in Mandarin, this investigation explores how monolingual, bilingual, and trilingual adults process their speech production differently using cognitive control mechanisms. In this study we conducted two experiments involving speech production in Mandarin. In the two experiments, 81 adults participated and were categorized into three groups: Mandarin monolingual, Hakka-Mandarin bilingual, and Hakka-Mandarin-Minnan trilingual. In Experiment 1 (unpreprogrammed task), each subject read 250 targets that were presented on a computer screen, one at a time, using E-prime; in Experiment 2 (preprogrammed task), each subject read 466 targets printed on A4 paper. Experiment 1 showed that bilinguals and trilinguals outperformed monolinguals in every aspect examined in this research, revealing the presence of bilingual and trilingual advantages in inhibitory control. Interestingly, in Experiment 2, we found a more complex pattern of results: a trilingual advantage in attentional control occurred during L2 production in terms of the number of errors and error correction; however, the bilingual group did not maintain this advantage in the task requiring attentional control. These experimental results revealed that the differences between the language groups became clearer when the inhibitory control demands increased and that compared with the trilingual advantage, the bilingual advantage in inhibitory control emerged in more limited contexts.     

Thinking about others and the future: Neural correlates of perspective taking relate to preferences for delayed rewards

We infer the thoughts and feelings of others by taking their perspectives. Similar processes could be used to understand how we will be affected by future events, by allowing us to take the perspective of our future self. In this paper, we test this idea using a previously presented framework for guiding predictions. The framework proposes that a shared neural mechanism is involved in controlling egocentric bias, both while shifting our perspective away from self and towards others, and while shifting our perspective from immediate to future perspectives. To test this framework, 36 adults performed an intertemporal choice task. They were then scanned using 3T functional magnetic resonance imaging while completing a false-belief “localizer” task, which requires egocentric bias control. A positive correlation was observed between the right temporoparietal junction (rTPJ) response during the false-belief task, and preferences for delayed rewards in intertemporal choices. A subset of participants performed the intertemporal choice task again in the scanner, which revealed that the response of the same rTPJ cluster, individually localized during the false-belief task, was higher during delayed over immediate reward choices. In addition, functional connectivity between the rTPJ and ventromedial prefrontal cortex was found to differ between immediate and delayed choices. The current results indicate an overlap in processes of egocentric bias control and those that determine preferences in intertemporal choices, offering a social cognitive explanation for why rewards are devalued with delay in temporal discounting.