Hippocampus is required for paired associate memory with neither delay nor trial uniqueness

Cued retrieval of memory is typically examined with delay when testing hippocampal functions, as in delayed matching-to-sample tasks. Equally emphasized in the literature, on the other hand, is the hippocampal involvement in making arbitrary associations. Paired associate memory tasks are widely used for examining this function. However, the two variables (i.e., delay and paired association) were often mixed in paired associate tasks, and this makes it difficult to localize the cognitive source of deficits with hippocampal perturbation. Specifically, a few studies have recently shown that rats can learn arbitrary paired associations between certain locations and nonspatial items (e.g., object or flavor) and later can retrieve the paired location when cued by the item remotely. Such tasks involve both (1) delay between sampling the cue and retrieving the target location and (2) arbitrary association between the cueing object and its paired location. Here, we tested whether delay was necessary in a cued paired associate task by using a task in which no delay existed between object cueing and the choice of its paired associate. Moreover, fixed associative relationships between the cueing objects and their paired locations were repeatedly used, thus involving no trial-unique association. Nevertheless, inactivations of the dorsal hippocampus with muscimol severely disrupted retrieval of paired associates, whereas the same manipulations did not affect discriminating individual objects or locations. The results powerfully demonstrate that the hippocampus is inherently required for retrieving paired associations between objects and places, and that delay and trial uniqueness of the paired associates are not necessarily required.     

Social deviance activates the brain’s error-monitoring system

Social psychologists have long noted the tendency for human behavior to conform to social group norms. This study examined whether feedback indicating that participants had deviated from group norms would elicit a neural signal previously shown to be elicited by errors and monetary losses. While electroencephalograms were recorded, participants (N = 30) rated the attractiveness of 120 faces and received feedback giving the purported average rating made by a group of peers. The feedback was manipulated so that group ratings either were the same as a participant’s rating or deviated by 1, 2, or 3 points. Feedback indicating deviance from the group norm elicited a feedback-related negativity, a brainwave signal known to be elicited by objective performance errors and losses. The results imply that the brain treats deviance from social norms as an error.     

Comparing patterns of component loadings: Principal Component Analysis (PCA) versus Independent Component Analysis (ICA) in analyzing multivariate non-normal data

Principal component analysis identifies uncorrelated components from correlated variables, and a few of these uncorrelated components usually account for most of the information in the input variables. Researchers interpret each component as a separate entity representing a latent trait or profile in a population. However, the components are guaranteed to be independent and uncorrelated only when the multivariate normality of the variables is assumed. If the normality assumption does not hold, components are guaranteed to be uncorrelated, but not independent. If the independence assumption is violated, each component cannot be uniquely interpreted because of contamination by other components. Therefore, in the present study, we introduced independent component analysis, whose components are uncorrelated and independent even when the multivariate normality assumption is violated, and each component carries unique information.     

The real you? The role of visual cues and comment congruence in perceptions of social attractiveness from facebook profiles

The purpose of this study was to examine the effects of social cues in self-presentations and the congruence of other-generated comments with the self-presentation in people's evaluations of a profile owner. A 2 (level of social cues: high vs. low) × 2 (congruent vs. incongruent) × 2 (order) × 2 (multiple messages) mixed-subject experiment was conducted with 104 college students. The results showed that a profile owner was perceived less socially attractive when other-generated comments were incongruent with the profile owner's self-presentation. No matter how people package themselves with extravagant self-presentations, it cannot be very successful without validation from others. Interestingly, an interaction effect between congruence and the level of social cues suggested that perceived popularity was low in the incongruent condition regardless of level of social cue. Theoretical and practical implications were also discussed.     

The integrated model of smartphone adoption: hedonic and utilitarian value perceptions of smartphones among korean college students

Abstract This study aims to propose an integrated model of smartphone adoption that incorporates social influences (SIs), perceived technicality, as well as hedonic and utilitarian attitudes into the technology acceptance model. The proposed model was empirically evaluated by using survey data collected from 239 Korean college students to investigate their perception and attitudes toward smartphone adoption intention. Our results show that users' attitudes and their adoption intention are highly influenced by SI and positive self-image. This implies that a smartphone is a symbolic product that can signal affiliation and enhance the users' status in a group. The results also indicate that hedonic enjoyment is equally important as utilitarian usefulness in predicting the adoption intention, and the two variables mediate the relationships between SI, positive self-image, perceived technicality, and the intention to use. Consequently, the results reveal that smartphones are convergent media that can be viewed as both task-oriented and entertainment-oriented devices.     

Neurocognitive development in 5- to 16-year-old North American children: A cross-sectional study

Executive functions are thought to be the latest functions to mature. However, this view has not been tested by assessing simultaneously memory, perception of emotions, visuospatial perception, and visuoconstructional skills. NEPSY II norm data from 1000 5- to 16-year-old U.S. children were obtained. Fifteen NEPSY II subtests with no floor or ceiling effects in any age group and no major changes in task type were selected. The 16-year level was attained at age 12 to 13 in all subtests with two exceptions: social perception (age 10 to 11) and narrative memory (age 14). Trend analyses showed that development was rapid in the age range 5 to 9 years followed by a deceleration in the rate of development. Peak performances were reached at 14 to 16 years but later in some subtests representing executive functions, verbal memory, and visuospatial performance. Thus, the study specified developmental time tables of neurocognitive functions. It demonstrated that not only executive functions but also verbal memory and visuospatial performance continue to develop beyond age 16.     

Hydrogenation of Ti50Zr25Co25 amorphous ribbons and its effect on their structural and mechanical properties

Changes in the structure and mechanical properties of Ti₅₀Zr₂₅Co₂₅ melt-spun ribbons upon electrolytic hydrogenation have been investigated. Structural analyses of the as-spun ribbons revealed the sporadic presence of icosahedral (i) quasicrystalline short-range order (SRO) in the amorphous structure. Upon cathodic charging with hydrogen, the i-SRO vanished for a hydrogen content of about 21 at.% (hydrogen-to-metal atom ratio, H/M: 0.26), resulting in a fully amorphous structure. Simultaneously, the fracture strength was found to increase while the ribbons preserved their bending ductility. However, a significant reduction in the fracture strength and ductility of the ribbons was observed for hydrogen concentrations larger than 26 at.%. Variations in the mechanical stability are discussed based on a structure-property correlation.     

Orthorhombic approximant phases and their relation to quasicrystals in mechanically alloyed Al–Cu–Fe–Si alloys

The possibility of synthesis of quasicrystalline and associated approximant phases during mechanical alloying and subsequent heat treatment of Al₆₅Cu₂₀Fe₁₀Si₅ alloy powders has been investigated. It is shown that, in addition to the stable ordered quasicrystal and 1/1 cubic approximant, two more phases having orthorhombic symmetry coexist. The a and c parameters of both these phases are similar to the lattice parameters of the cubic approximant, whereas their b parameters are, respectively, three and four times larger than the c parameters. It is suggested that these phases evolve on account of local symmetry breaking of the cubic approximant phase, possibly due to ordering.     

Varieties of Cues to Emotion in Naturally Occurring Situations

People were asked to observe a person with whom they lived, to report when they noticed that person experiencing an emotion, and to report what cues they used to detect the emotion. In Phase 1, observers were told to "list the cues they used"; in Phase 2, they were told to "describe how they could tell" that the target person was experiencing an emotion. Results were similar in both phases. Only 5 of the 182 respondents reported using a single cue whereas 10 reported using at least a dozen cues. Two out of three respondents reported using vocal cues; over a half reported using facial, indirect verbal, and context cues; nearly a half reported using body and activity cues; about a quarter of the respondents reported using physiological, trait, and other cues; and fewer than a tenth reported using direct verbal cues. Roughly the same number of cues and the same distribution of cue categories was found regardless of the emotion being observed, the sex of the person observing, the sex of the person being observed, or the type of relationship between them.     

A Population Study of Victimization, Relationships, and Well-Being in Middle Childhood

The paper presents a population-based study on the association of victimization and peer and adult relationships with children’s life satisfaction, self-esteem, anxiety, and depressive symptoms. The study extends previous research by examining 2-, 3-, and 4-way higher-order interaction effects (moderation hypotheses) of adults and peer relationships, victimization, and gender on positive and negative aspects of children’s well-being. The study draws from a representative population-level sample of 2,792 4th graders (M _age = 9.70 years; 48.2 % girls). Data were obtained via student self-report survey on the Middle Years Development Instrument (MDI). Given the nested data (children within classrooms), we employed multi-level regression analyses. Positive relationships with adults and peers were most strongly associated with life satisfaction and self-esteem, whereas victimization was most strongly associated with depressive symptoms and anxiety. No significant 2- or 3-way interactions were identified. The 4-way interaction of gender, adult connectedness, peer connectedness, and victimization was significant for three outcomes; that is, victimization was particularly strongly associated with low life satisfaction, low self-esteem, and high depressive symptoms for girls with low self-reports of peer and adult connectedness. The findings have implications for promoting children’s well-being in school and community contexts, corroborating interventions that foster relationship-building skills and simultaneously reduce victimization.