Sleep deprivation impairs object recognition in mice

Many studies in animals and humans suggest that sleep facilitates learning, memory consolidation, and retrieval. Moreover, sleep deprivation (SD) incurred after learning, impaired memory in humans, mice, rats, and hamsters. We investigated the importance of sleep and its timing in an object recognition task in OF1 mice subjected to 6h SD either immediately after the acquisition phase (0-6 SD) or 6h later (7-12 SD), and in corresponding undisturbed controls. Motor activity was continuously recorded with infrared sensors. All groups explored two familiar, previously encountered objects to a similar extent, both at the end of the acquisition phase and 24h later during the test phase, indicating intact familiarity detection. During the test phase 0-6 SD mice failed to discriminate between the single novel and the two familiar objects. In contrast, the 7-12 SD group and the two control groups explored the novel object significantly longer than the two familiar objects. Plasma corticosterone levels determined after SD did not differ from time-matched undisturbed controls, but were significantly below the level measured after learning alone. ACTH did not differ between the groups. Therefore, it is unlikely that stress contributed to the memory impairment. We conclude that the loss of sleep and the activities the mice engaged in during the SD, impaired recognition memory retrieval, when they occurred immediately after acquisition. The delayed SD enabled memory consolidation during the 6h when the mice were allowed to sleep, and had no detrimental effect on memory. Neither SD schedule impaired object familiarity processing, suggesting that only specific cognitive abilities were sensitive to the intervention. Sleep may either actively promote memory formation, or alternatively, sleep may provide optimal conditions of non-interference for consolidation.     

Inter- and intra-group variability in perceptions of behavior among Asian Americans and European Americans

Between-group and within-group differences in perceptions of behavior were examined among 74 Asian Americans and 111 European Americans. Participants rated videotaped interactions of Asian American mothers and daughters. Asian Americans, and a more homogeneous sample of Chinese Americans, perceived less maternal control and more reciprocity than did European Americans. Intra-cultural variations in perceptions were also evident, as within-group analyses revealed differences in perceptions based on the generational status of Asian Americans and the degree of multicultural experience of European Americans. Overall, findings suggest that perceptions of behavior are shaped as much by within-group differences in familiarity and experience with the target culture as by between-group differences in ethnicity. Implications for theories of child socialization, multicultural counseling, and observational research are discussed.     

Do humans and baboons use the same information when categorizing human and baboon faces?

What information is used for sorting pictures of complex stimuli into categories? We applied a reverse correlation method to reveal the visual features mediating categorization in humans and baboons. Two baboons and 6 humans were trained to sort, by species, pictures of human and baboon faces on which random visual noise was superimposed. On ambiguous probe trials, a human-baboon morph was presented, eliciting "human" responses on some trials and "baboon" responses on others. The difference between the noise patterns that induced the two responses made explicit the information mediating the classification. Unlike the humans, the baboons based their categorization on information that closely matched that used by a theoretical observer responding solely on the basis of the pixel similarities between the probe and training images. We show that the classification-image technique and principal components analysis provide a method to make explicit the differences in the information mediating categorization in humans and animals.     

The singularity of being: Lacan and the immortal within

Drawing on the work of Eric Santner, Slavoj ?i?ek, and Alenka Zupan?i?, this paper constructs a theory of subjective singularity from a Lacanian perspective. It argues that, unlike the "subject" (who comes into existence as a result of symbolic prohibition), or the "person" (who is aligned with the narcissistic conceits of the imaginary), the singular self emerges in response to a galvanizing directive arising from the real. This directive summons the individual to a "character" beyond his or her social and intersubjective investments. Consequently, singularity expresses the individual's nonnegotiable distinctiveness, eccentricity, or idiosyncrasy at the same time as it prevents both symbolic and imaginary closure. It opens to layers of rebelliousness that indicate that there are components of human life that exceed the realm of normative sociality. Indeed, insofar as singularity articulates something about the "undead" pulse of jouissance, it connects the individual to a paradoxical kind of immortality. This does not mean that the individual will not die, but rather that he or she is capable of "transcendent" experiences, such as heightened states of creativity, that (always momentarily) reach "outside" the parameters of mortal life. Such experiences allow the individual to feel "real" in ways that fend off symbolic abduction and psychic death.     

Symbolic and nonsymbolic number comparison in children with and without dyscalculia

Developmental dyscalculia (DD) is a pervasive difficulty affecting number processing and arithmetic. It is encountered in around 6% of school-aged children. While previous studies have mainly focused on general cognitive functions, the present paper aims to further investigate the hypothesis of a specific numerical deficit in dyscalculia. The performance of 10- and 11-year-old children with DD characterised by a weakness in arithmetic facts retrieval and age-matched control children was compared on various number comparison tasks. Participants were asked to compare a quantity presented in either a symbolic (Arabic numerals, number words, canonical dots patterns) or a nonsymbolic format (noncanonical dots patterns, and random sticks patterns) to the reference quantity 5. DD children showed a greater numerical distance effect than control children, irrespective of the number format. This favours a deficit in the specialised cognitive system underlying the processing of number magnitude in children with DD. Results are discussed in terms of access and representation deficit hypotheses.     

Mimicking disliked others: Effects of a priori liking on the mimicry‐liking link

The sharing of bodily states elicits in mimicker and mimickee corresponding conceptualisations, which facilitates liking. There are many studies showing the relatedness of mimicry and liking. However, the mimicry‐liking link has not been investigated under conditions in which the mimickee is liked or disliked a priori. In two studies, we examined moderating effects of a priori liking on the mimicry‐liking link. Liking was measured via self‐report measures (Studies 1 and 2) and behavioural measures using a virtual environment technology (Study 2). Results showed that when participants intentionally mimicked a disliked person, liking for that person was not improved, whereas when participants mimicked a liked person, liking for that person increased. These effects were shown to be mediated by affiliation. These studies not only provided further evidence of a link between mimicry and liking, but also demonstrated that this relationship is moderated by a priori liking. Copyright © 2009 John Wiley & Sons, Ltd.     

Prejudice in the police: On the processes underlying the effects of selection and group socialisation

The principal aim of this study is to determine why police officers are generally found to be more prejudiced towards disadvantaged groups than are the standard population. Two independent processes were expected to account for this effect: Selection and group socialisation. Using a cross‐sectional design (N = 170), firstly, we compared, newly recruited police officers with a control population (selection effect), and secondly, police officers with 1 year of training with the newly recruited ones (group socialisation effect). Results reveal a significant effect of both selection and group socialisation, the two being underlined by distinct processes; right‐wing authoritarianism (RWA) in the case of the former and internalisation of a prejudice norm in the case of the latter. Finally, the results show that group identification moderates the change in internalisation of the prejudice norm. Copyright © 2009 John Wiley & Sons, Ltd.     

Outline of a general model of measurement

Measurement is a process aimed at acquiring and codifying information about properties of empirical entities. In this paper we provide an interpretation of such a process comparing it with what is nowadays considered the standard measurement theory, i.e., representational theory of measurement. It is maintained here that this theory has its own merits but it is incomplete and too abstract, its main weakness being the scant attention reserved to the empirical side of measurement, i.e., to measurement systems and to the ways in which the interactions of such systems with the entities under measurement provide a structure to an empirical domain. In particular it is claimed that (1) it is on the ground of the interaction with a measurement system that a partition can be induced on the domain of entities under measurement and that relations among such entities can be established, and that (2) it is the usage of measurement systems that guarantees a degree of objectivity and intersubjectivity to measurement results. As modeled in this paper, measurement systems link the abstract theory of measuring, as developed in representational terms, and the practice of measuring, as coded in standard documents such as the International Vocabulary of Metrology.     

Sign determination of the 57 Fe electric-field gradient in Al-based crystals and icosahedral quasicrystals

Abstract

The icosahedral quasicrystals i-AIMn, isomorphically substituted by 28 at.% Fe or by a mixture of (CrFe) atoms, have been studied for the first time by in-field Mössbauer spectroscopy in order to determine the sign and asymmetry parameter of the dominant electric-field gradient (EFG) term. In addition, the orthorhombic o-Al(MnFe) and cubic α- and hexagonal β-Al(MnFe)Si crystalline phases have been studied. We show that the previous Mössbauer results are inadequate for determining whether there are two sites in the quasicrystalline structure in the ratio of the golden number. Our results for i-Al(MnFe) show that the dominant EFG is negative, with an asymmetry parameter of about 0·6. For i-Al(CrFe), essentially no deviations are found from the model of Czjzek or the Gaussian isotropic model. One crystalline phase, the hexagonal β phase, is found to have a very similar quadrupole effect to that found in i-Al(MnFe). In addition it is found that this phase undergoes a change which is at least partly of magnetic origin.