High-fat diets impair spatial learning in the radial-arm maze in mice

It has been suggested that hyperglycemia and insulin resistance triggered by energy-dense diets can account for hippocampal damage and deficits of cognitive behaviour. We wonder if the impairment of learning and memory processes detected in diet-induced obese (DIO) mice is linked to diet composition itself. With this purpose we have evaluated learning performance in mice undergoing a short-term high-fat (HF) treatment, which leads to a pre-obese state characterized by increased adiposity without significant changes of glucose and insulin plasma levels. C57BL/6J mice were fed either a HF (45 kcal% from fat) or control diet (10 kcal% from fat) during 8 weeks. Learning performance was evaluated by using the four-arm baited version of the eight-arm radial maze test (RAM). Mice were trained to learn the RAM protocol and then memory was tested at different time-points. Time spent to consume food placed in baited arms and errors committed to find them were measured in all sessions. DIO mice significantly spent more time in learning the task and made a greater number of errors than controls. Moreover, retention tests revealed that both working and total memory errors were also more numerous in DIO mice. The current results show that short-term DIO impairs spatial learning and suggest that impairment of hippocampal learning elicited by HF diets might be perceptible before metabolic alterations linked to obesity develop.     

Experiences and perspectives of African American, Latina/o, Asian American, and European American psychology graduate students: A national study

A national, Web-based survey of 1,219 African American, Latina/o, Asian American, and European American psychology graduate students revealed both similarities and differences in experiences and perspectives. Mentoring was found to be the strongest predictor of satisfaction across groups. Academic supports and barriers, along with perceptions of diversity within the academic environment, were also important predictors of satisfaction. Students of color perceived less fairness of representation of their ethnic group within psychology than European American students, and a greater linkage between aspects of the graduate school experience and their ethnicity. Limitations of the study and implications for future research and action are discussed.     

Communication in social networks: Effects of kinship,network size,and emotional closeness

Communication is important in preventing social relationships from decaying over time. This study examined the effects of social network size, emotional closeness, and type of relationship (kinship vs. friendship) on communication patterns in the social networks of 251 women. Participants with large kin networks had longer times to last contact to both kin and friends. Participants with high levels of emotional closeness in their networks had shorter times to last contact. The effect of emotional closeness on time to last contact was greater for kin than for friends. These results demonstrate that time to last contact is closely tied to emotional closeness and suggest that the costs of maintaining kin relationships are lower than the costs of maintaining friendships.     

Friend or foe? The role of latent inhibition in predator and non-predator labelling by coral reef fishes

In communities of high biodiversity, the ability to distinguish predators from non-predators is crucial for prey success. Learning often plays a vital role in the ability to distinguish species that are threatening from those that are not. Many prey animals learn to recognise predators based on a single conditioning event whereby they are exposed to the unknown predator at the same time as alarm cues released from injured conspecifics. The remarkable efficiency of such learning means that recognition mistakes may occur if prey inadvertently learn that a species is a predator when it is not. Latent inhibition is a means by which prey that are pre-exposed to an unknown species in the absence of negative reinforcement can learn that the unknown animal is likely not a threat. Learning through latent inhibition should be conservative because mistakenly identifying predators as non-predators can have fatal consequences. In this study, we demonstrated that a common coral reef fish, lemon damselfish, Pomacentrus moluccensis can learn to recognise a predator as non-threatening through latent inhibition. Furthermore, we showed that we could override the latent inhibition effect by conditioning the prey to recognise the predator numerous times. Our results highlight the ability of prey fish to continually update the information regarding the threat posed by other fishes in their vicinity.     

Physical cognition and tool-use: performance of Darwin’s finches in the two-trap tube task

The trap tube is a classic test of causal reasoning abilities in animals in the physical domain. Recently, a modified version of this task improved its diagnostic capacity and allowed testing of non-tool-using animals. We used this modified two-trap tube task to compare the cognition of two Darwin’s finch species: the woodpecker finch, Cactospiza pallida, a tool-using species, and the small tree finch, Camarhynchus parvulus, a closely related non-tool-using species. Not all woodpecker finches use tools in nature, and we therefore also tested non-tool-using individuals to assess the effect of experience on trap tube performance. No small tree finches and only two non-tool-using woodpecker finches solved the initial task which was operated using a pre-inserted piston. One tool-using woodpecker finch solved the task when allowed to use its own tool instead of the pre-inserted piston. The fact that none of these subjects transferred their knowledge when the features of the task changed, suggests that in this species, neither experience using tools nor the genetic composition of a tool-user are associated with the general physical cognitive skills required to solve the trap tube task.     

A Tuesday in the life of a flourisher: the role of positive emotional reactivity in optimal mental health

Flourishing--a state of optimal mental health--has been linked to a host of benefits for the individual and society, including fewer workdays lost and the lowest incidence of chronic physical conditions. The aim of this paper was to investigate whether and how routine activities promote flourishing. The authors proposed that flourishers thrive because they capitalize on the processes featured in the broaden-and-build theory of positive emotions, specifically by experiencing greater positive emotional reactivity to pleasant events and building more resources over time. To test these hypotheses, the Day Reconstruction Method (DRM) was administered to a prescreened community sample of adults (n = 208), and they were recontacted two to three months later. Results showed that relative to those who did not flourish or were depressed, people who flourish generally responded with bigger "boosts" in positive emotions in response to everyday, pleasant events (helping, interacting, playing, learning, spiritual activity), and this greater positive emotional reactivity, over time, predicted higher levels of two facets of the cognitive resource of mindfulness. In turn, these higher levels of mindfulness were positively associated with higher levels of flourishing at the end of study, controlling for initial levels of flourishing. These results suggest that the promotion of well-being may be fueled by small, yet consequential differences in individuals' emotional experience of pleasant everyday events. Additionally, these results underscore the utility of the broaden-and-build theory in understanding the processes by which flourishing is promoted and provide support for a positive potentiation perspective.     

Discriminating between the effects of valence and salience in the Implicit Association Test

The Implicit Association Test (IAT) is the most widely used indirect measure of attitudes in social psychology. It has been suggested that artefacts such as salience asymmetries and familiarity can influence performance on the IAT. Chang and Mitchell (2009) proposed that the ease with which IAT stimuli are classified (classification fluency) is the common mechanism underlying both of these factors. In the current study, we investigated the effect of classification fluency on the IAT and trialled a measure-the split IAT-for dissociating between the effects of valence and salience in the IAT. Across six experiments, we examined the relationship between target classification fluency and salience asymmetries in the IAT. In the standard IAT, the more fluently classified target category was, all else being equal, compatible with pleasant attributes over unpleasant attributes. Furthermore, the more fluently classified target category was more easily classified with the more salient attribute category in the split IAT, independent of evaluative associations. This suggests that the more fluently classified category is also the more salient target category.     

Shared service centers and professional employability

This paper presents case study evidence of evolutionary changes in business support functions resulting in a fundamental hollowing out of the professional space over time and distance, creating the ‘hourglass’ profession. In an IT-enabled, boundaryless world, many professional activities can now be undertaken, in the manner of the Martini slogan, ‘any time, any place, anywhere’.This paper aims:

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  To investigate the shared service center as an emerging organizational form with the potential to drive fundamental change in the nature and location of professional work.

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  To explore the impact of these changes for individual professional workers, and to highlight the need for a greater focus on individual employability as the driver of an overall career trajectory.

     

Use of social network sites and instant messaging does not lead to increased offline social network size, or to emotionally closer relationships with offline network members

The effect of Internet use on social relationships is still a matter of intense debate. This study examined the relationships between use of social media (instant messaging and social network sites), network size, and emotional closeness in a sample of 117 individuals aged 18 to 63 years old. Time spent using social media was associated with a larger number of online social network "friends." However, time spent using social media was not associated with larger offline networks, or feeling emotionally closer to offline network members. Further, those that used social media, as compared to non-users of social media, did not have larger offline networks, and were not emotionally closer to offline network members. These results highlight the importance of considering potential time and cognitive constraints on offline social networks when examining the impact of social media use on social relationships.     

Can I trust you? Negative affective priming influences social judgments in schizophrenia

Successful social interactions rely on the ability to make accurate judgments based on social cues as well as the ability to control the influence of internal or external affective information on those judgments. Prior research suggests that individuals with schizophrenia misinterpret social stimuli and this misinterpretation contributes to impaired social functioning. We tested the hypothesis that for people with schizophrenia, social judgments are abnormally influenced by affective information. Twenty-three patients with schizophrenia and 35 healthy control participants rated the trustworthiness of faces following the presentation of neutral, negative (threat-related), or positive affective primes. Results showed that all participants rated faces following negative affective primes as less trustworthy than faces following neutral or positive primes. Importantly, this effect was significantly more pronounced for participants with schizophrenia, suggesting that schizophrenia may be characterized by an exaggerated influence of negative affective information on social judgment. Furthermore, the extent that the negative affective prime influenced trustworthiness judgments was significantly associated with patients' severity of positive symptoms, particularly feelings of persecution. These findings suggest that for people with schizophrenia, negative affective information contributes to an interpretive bias, consistent with paranoid ideation, when judging the trustworthiness of others. This bias may contribute to social impairments in schizophrenia.