NR2B downregulation in a forebrain region required for avian vocal learning is not sufficient to close the sensitive period for song learning

The neural changes that limit the sensitive period for avian song development are unknown, but neurons in a forebrain region critical for song learning, the lMAN, exhibit experience-driven changes in NMDAR subunit expression that could regulate sensitive period closure. Specifically, NR2B levels in lMAN decrease during song acquisition, potentially reducing synaptic plasticity by decreasing NMDAR EPSC duration and/or affecting NMDAR-coupled intracellular cascades. While rearing birds in isolation extends the sensitive period and also delays the developmental changes in NR2B expression and NMDAR physiology, recent work indicates that a transition to faster NMDAR currents does not preclude further song learning. However, NR2B mRNA expression in isolates remains elevated beyond the age at which NMDAR currents shorten, leaving open the possibility that NR2B levels regulate closure of the sensitive period through effects other than those mediated by NMDAR current duration. To determine whether the experience-driven decrease in NR2B expression in lMAN closes the sensitive period, we promoted this change in gene expression either by treating isolation-reared zebra finches briefly with testosterone (T-isolates) or by allowing males limited access to conspecific song (pre-exposed isolates). We then assessed if these birds could acquire song from tutors after the normal close of the sensitive period. Despite a normal decline in NR2B expression, T-isolate and pre-exposed isolate birds learned tutor songs heard from d65-90, while normally reared birds did not. These findings suggest that the normal decline in NR2B expression with lMAN is not sufficient for sensitive period closure.     

Using the expectation maximization algorithm to estimate coefficient alpha for scales with item-level missing data

A 2-step approach for obtaining internal consistency reliability estimates with item-level missing data is outlined. In the 1st step, a covariance matrix and mean vector are obtained using the expectation maximization (EM) algorithm. In the 2nd step, reliability analyses are carried out in the usual fashion using the EM covariance matrix as input. A Monte Carlo simulation examined the impact of 6 variables (scale length, response categories, item correlations, sample size, missing data, and missing data technique) on 3 different outcomes: estimation bias, mean errors, and confidence interval coverage. The 2-step approach using EM consistently yielded the most accurate reliability estimates and produced coverage rates close to the advertised 95% rate. An easy method of implementing the procedure is outlined.     

Are coping resources related to humoral reaction induced by academic stress? An analysis of specific salivary antibodies to Epstein-Barr virus and cytomegalovirus

The aim of the present study was to investigate whether coping resources mediated the changes in Epstein-Barr virus (EBV) and human cytomegalovirus (HCMV) specific salivary antibodies caused by academic stress. Fifty-four first-year female students of nursing and physiotherapy completed pencil and paper written questionnaires and concurrently donated saliva samples. The instrument included the short version of the Sense of Coherence (SOC) scale, measures of social support, current health, health practices, the scale of psychological distress, and state anxiety questionnaire. Data and saliva samples were collected one month after the beginning of the first semester, during term examinations period and a month into the second semester. Statistically significant changes in the level of specific salivary EBV and HCMV antibodies were observed between the four study points. State anxiety and psychological distress were significantly associated with HCMV-specific salivary antibody level increase during examinations and its decrease after the stress was over. Coping resources, however, were not associated with changes in any of the antibodies studied.     

Computerizing reading training: Evaluation of a latent semantic analysis space for science text

The effectiveness of a domain-specific latent semantic analysis (LSA) in assessing reading strategies was examined. Students were given self-explanation reading training (SERT) and asked to think aloud after each sentence in a science text. Novice and expert human raters and two LSA spaces (general reading, science) rated the similarity of each think-aloud protocol to benchmarks representing three different reading strategies (minimal, local, and global). The science LSA space correlated highly with human judgments, and more highly than did the general reading space. Also, cosines from the science LSA spaces can distinguish between different levels of semantic similarity, but may have trouble in distinguishing local processing protocols. Thus, a domain-specific LSA space is advantageous regardless of the size of the space. The results are discussedin the context of applying the science LSA to a computer-based version of SERT that gives online feedback based on LSA cosines.     

Representing properties locally

Theories of knowledge such as feature lists, semantic networks, and localist neural nets typically use a single global symbol to represent a property that occurs in multiple concepts. Thus, a global symbol represents mane across HORSE, PONY, and LION. Alternatively, perceptual theories of knowledge, as well as distributed representational systems, assume that properties take different local forms in different concepts. Thus, different local forms of mane exist for HORSE, PONY, and LION, each capturing the specific form that mane takes in its respective concept. Three experiments used the property verification task to assess whether properties are represented globally or locally (e.g., Does a PONY have mane?). If a single global form represents a property, then verifying it in any concept should increase its accessibility and speed its verification later in any other concept. Verifying mane for PONY should benefit as much from having verified mane for LION earlier as from verifying mane for HORSE. If properties are represented locally, however, verifying a property should only benefit from verifying a similar form earlier. Verifying mane for PONY should only benefit from verifying mane for HORSE, not from verifying mane for LION. Findings from three experiments strongly supported local property representation and ruled out the interpretation that object similarity was responsible (e.g., the greater overall similarity between HORSE and PONY than between LION and PONY). The findings further suggest that property representation and verification are complicated phenomena, grounded in sensory-motor simulations.     

The limitations of orthographic analogy in early reading development: performance on the clue-word task depends on phonological priming and elementary decoding skill, not the use of orthographic analogy

Two experiments investigated the mechanisms underlying analogical transfer in the clue-word reading task developed by Goswami and her colleagues. Across both experiments, an equivalent number of "analogy" responses were made regardless of whether the clue word was seen or just heard. In addition, the number of "analogy" responses to words sharing both orthographic and phonological overlap with the clue words was no greater than that shown to words sharing only pronunciations. These results provide no evidence for the view that beginning readers make genuine orthographic-based analogies. Instead, the findings are interpreted within a framework in which phonological priming, in combination with the children's own partial decoding attempts based on limited orthographic knowledge, account for their performance on the clue-word task. It is concluded that the extent to which beginning readers make orthographic analogies is overestimated and as a consequence, theories that emphasize the importance of orthographic analogy as a mechanism driving the development of early reading skills need to be questioned.     

Reexposure breeds recall: effects of experience on 9-month-olds' ordered recall

On the basis of three experiences, 9-month-olds recall specific events after one month. We tested whether multiple experiences are necessary, or merely facilitative, of 9-month-olds' long-term recall. In two experiments, using deferred imitation, infants were exposed to multi-step sequences either one time, two times, or three times prior to a one-month delay. In Experiment 1, regardless of the number of experiences, infants did not demonstrate recall. In Experiment 2, infants were tested on and reexposed to the events after one week; recall was tested again one month later. Performance after 1 week in Experiment 2 was greater than performance after one month in Experiment 1. Moreover, presumably as a function of reexposure after one week, infants recalled the individual actions of the events one month later. Infants in the three-experience condition also evidenced ordered recall after one month. Implications for the developmental status of the neural substrate supporting long-term recall are discussed.     

Neuroticism and social comparison orientation as moderators of affective responses to social comparison at work

In a study among 72 nurses, the affective consequences of social comparison were examined and related to neuroticism (N) and to social comparison orientation (SCO). Participants were confronted with a bogus interview with an upward versus a downward comparison target. Positive affect and identification were higher, and negative affect was lower, in the upward than in the downward comparison condition. Independent of their SCO, the higher individuals were in N, the less they identified with the upward comparison target, the more they identified with the downward comparison target, and the less positive affect they showed following confrontation with the upward comparison target. In contrast, independent of their level of N, the higher individuals were in SCO, the more negative affect they showed following confrontation with the downward comparison target. The effects on negative affect stayed the same when controlling for positive affect, and the effects on positive affect stayed the same when controlling for negative affect. These effects were also obtained when perceived direction was used as a predictor instead of the experimentally manipulated direction. It is concluded that, although N and SCO are correlated, these variables seem to have independent and distinct effects upon the responses to social comparison information.     

Contextual connections to puns in fables: perceived humor

Adding material that provided an associative connection to a pun enhances perceived humor, as shown in a previous series of studies. Because those results had been based on one-sentence statements that may have relied, in part, on brevity for humor, the purpose of the present study was to evaluate reactions to context and puns (mostly spoonerisms) with more lengthy material to add generality to those findings. Three within-subject studies were conducted in which short fables were manipulated systematically such that the final sentence was or was not a pun and contextual information pertaining to both meanings of the pun was or was not present in the body of the stories. Results showed that the pun itself was a powerful contributor to perceived humor and cleverness and that contextual information amplified those perceptions. Arousal, surprise, and detection of appropriate incongruity are discussed.