Associative learning over trials activates the hippocampus in healthy elderly but not mild cognitive impairment

The ability to form associations between choice alternatives and their contingent outcomes is an important aspect of learning that may be sensitive to hippocampal dysfunction in memory disorders of aging such as amnestic mild cognitive impairment (MCIa), or early Alzheimer disease. In this preliminary study we examined brain activation using functional magnetic resonance imaging (fMRI) in 12 healthy elderly participants and nine patients with MCIa during an associative learning task. Using a high-field 3.0-Tesla MRI scanner, we examined the dynamic neural response during associative learning over trials. The slope of signal attenuation associated with learning was analyzed for differences between groups within an a priori defined hippocampal region. Results indicated dynamic signal attenuation associated with learning in the healthy elderly sample, but not in MCIa. The absence of an associative learning effect in the MCIa sample reaffirms an important link between the learning difficulties that are commonly encountered in MCIa and the mesial temporal region.     

Loss is a loss,why categorize it? Mental accounting across cultures

Consumers regularly track their expenses and assign them to categories like food, entertainment, and clothing, which is popularly known as mental accounting. In this paper, we show that consumption biases that result from mental accounting—underconsumption or overconsumption—are not prevalent in Easterners due to their holistic thinking style, whereas Westerners exhibit such biases due to their analytic thinking style. In Study 1, we collected data with Easterners (students from the eastern part of India) and show that they do not exhibit mental accounting biases as is seen in Westerners. In Study 2, we show that such differences in mental accounting across cultures result from their thinking styles by manipulating thinking styles within a Western population (American students from the Midwest). We also show that the differences in styles of thinking across cultures motivate two different types of accounting processes—a piecemeal accounting process in the Westerners and a comprehensive accounting process in the Easterners—which in turn influence the differences in mental accounting biases across cultures. This finding adds to the growing literature in cross‐cultural differences in consumer decision making and explores how and why a well‐documented robust effect, mental accounting, varies with the cultural background of the consumers.     

The effects of counterfeiting on consumer search

• Counterfeit products and the brand pirates who make, distribute, and sell them continue to be a challenge for many marketers around the globe. Estimates of global sales for bogus products are in the hundreds of billions of dollars and recent evidence suggests that fakes are prevalent in both developed and developing countries. We investigate brand/product counterfeiting from a consumer search perspective. As the quality of counterfeits improves, it is becoming more difficult for the consumer to identify them. Interviews with 102 international informants yield a picture of the cues consumers use to detect counterfeits and the roles of face and taste in decisions to purchase or not to purchase fake goods. We conclude with a discussion of some managerial implications.

Copyright © 2006 John Wiley & Sons, Ltd.     

Cerebrospinal fluid concentrations of biogenic amines and corticotropin-releasing factor in adolescent non-human primates as a function of the timing of adverse early rearing

Adolescent bonnet macaques nursed as infants by mothers facing unpredictable requirements for food procurement (variable foraging demand, VFD) display persistent neurobiological disturbances. This study examined the long-term neurochemical and behavioral effects of adverse rearing initiated later in infancy than in previous cohorts of subjects to test the hypothesis that the timing of an early adverse experience would influence patterns of biobehavioral outcome. Cisternal cerebrospinal fluid (CSF) monoamine and corticotropin-releasing factor (CRF) concentrations were obtained from 20 bonnet macaques (11 VFD-reared and 9 normally reared controls) approximately 2 years after the end of differential rearing. VFD-reared primates displayed on multiple samplings significantly lower CSF CRF concentrations and higher CSF 5-hydroxyindoleacetic acid (5-HIAA) concentration compared to controls. In the VFD-reared, significant inverse correlations between CRF and all three monoamines were found (5-HIAA, 3-methoxy-4-hydroxyphenethyleneglycol and homovanillic acid), most prominently for 5-HIAA. In controls, but not VFD-reared subjects, CSF CRF was positively correlated with changes in "gregariousness" upon presentation of a fear stimulus. VFD-reared subjects displayed greater baseline hierarchical engagement than controls. In contrast to prior findings, in which rearing under VFD conditions at an earlier age led to increased CSF CRF compared with controls, CSF CRF was lower after later exposure to VFD rearing than in controls. Thus, the timing of exposure to VFD conditions early in life evidently determines whether CSF CRF was found to be elevated or decreased, within the context of increased serotonin metabolism, during the course of primate maturation.     

Pressure-induced structural transition in UGa2

High-pressure X-ray diffraction has been performed on UGa₂ up to 20?GPa using a diamond anvil cell. UGa₂ exhibits the AlB₂-type structure with space group P6/mmm at room temperature and atmospheric pressure. At about 16?GPa a reversible structural transformation to a tetragonal phase was observed. The bulk modulus of the AlB₂-type phase has been determined to be ～100?GPa, which is comparable to rare earth digallides like TmGa₂ and HoGa₂.     

Building Cognition: The Construction of Computational Representations for Scientific Discovery

Novel computational representations, such as simulation models of complex systems and video games for scientific discovery (Foldit, EteRNA etc.), are dramatically changing the way discoveries emerge in science and engineering. The cognitive roles played by such computational representations in discovery are not well understood. We present a theoretical analysis of the cognitive roles such representations play, based on an ethnographic study of the building of computational models in a systems biology laboratory. Specifically, we focus on a case of model‐building by an engineer that led to a remarkable discovery in basic bioscience. Accounting for such discoveries requires a distributed cognition (DC) analysis, as DC focuses on the roles played by external representations in cognitive processes. However, DC analyses by and large have not examined scientific discovery, and they mostly focus on memory offloading, particularly how the use of existing external representations changes the nature of cognitive tasks. In contrast, we study discovery processes and argue that discoveries emerge from the processes of building the computational representation. The building process integrates manipulations in imagination and in the representation, creating a coupled cognitive system of model and modeler, where the model is incorporated into the modeler's imagination. This account extends DC significantly, and we present some of the theoretical and application implications of this extended account.     

Working memory recall precision is a more sensitive index than span

Delayed adjustment tasks have recently been developed to examine working memory (WM) precision, that is, the resolution with which items maintained in memory are recalled. However, despite their emerging use in experimental studies of healthy people, evaluation of patient populations is sparse. We first investigated the validity of adjustment tasks, comparing precision with classical span measures of memory across the lifespan in 114 people. Second, we asked whether precision measures can potentially provide a more sensitive measure of WM than traditional span measures. Specifically, we tested this hypothesis examining WM in a group with early, untreated Parkinson's disease (PD) and its modulation by subsequent treatment on dopaminergic medication. Span measures correlated with precision across the lifespan: in children, young, and elderly participants. However, they failed to detect changes in WM in PD patients, either pre‐ or post‐treatment initiation. By contrast, recall precision was sensitive enough to pick up such changes. PD patients pre‐medication were significantly impaired compared to controls, but improved significantly after 3 months of being established on dopaminergic medication. These findings suggest that precision methods might provide a sensitive means to investigate WM and its modulation by interventions in clinical populations.     

Gandhi’s Synthesis of Liberal and Communitarian Values: Its Basis and Insights

Journal of Indian Council of Philosophical Research - It is well known that notions of individual sovereignty, universal rights, and the duty to follow one’s own conscience are central to the...