Dexamethasone Does Not Prevent Seven-Day ADX-Induced Apoptosis in the Dentate Gyrus of the Rat Hippocampus

Long-term adrenalectomy (ADX) is known to result in apoptosis within the dentate gyrus of the rat hippocampus. While the underlying mechanism is still unclear, adrenal steroids appear to play a pivotal role in granule cell survival, as administration of the mineralocorticoid receptor (MR) agonists, corticosterone and aldosterone, to ADX rats results in protection against the ADX-induced effect. The consequence of administration of the glucocorticoid receptor (GR) agonists, dexamethasone and RU28362, however, is less clear, and either complete or only partial protection for the ADX animal has been reported. This study investigated further the role played by GR in the degenerative process. After establishing the characteristics of seven-day ADX-induced apoptosis in the young male Wistar rat, the effect of chronically-implanted, subcutaneous pellets containing various doses of dexamethasone and corticosterone, on ADX-induced apoptosis was studied. Both high and low doses of corticosterone were found to be protective. In contrast to some other studies, however, neither dose of dexamethasone had any obvious protective effect and rather seemed to increase apoptosis in dentate gyrus of intact animals. Intracerebroventricular infusion of dexamethasone for seven days was also found to be ineffective in preventing apoptosis, demonstrating that it is occupation of MR, rather than GR, which is crucial to dentate gyrus granule cell survival.     

Components of "authority" as determinants of compliance.

This study investigated factors affecting compliance, to orders from a formal authority. The design created a two-level status hierarchy in which subjects occupied identical low-status positions and responded to demands from a simulated high-status leader. Four components of authority-normativity,coervice power, collective justification, and success-failure-were manipulated as independent variables. Another component, the endorsement accorded the leader, was included in the design as a measured variable. Results indicated that compliance increased significantly when coervice power was high (rather than low), when justification was collective (rather than partisan), and when demands were normative (rather than counternormative). Contary ti the theoretical expectation, endorsement did not affect compliance by low-status members. The findings show that the normative aspect of legitimacy serves as a compliance-gaining base even when stripped of enforcing sanctions and under-lying goals and that the distinction between normativity and endorsement is valid for research on social power.     

Statistical problems in the evaluation of army tests

The introduction of psychological tests for personnel selection in the British forces has given rise to several novel problems in statistical procedure. The solutions proposed are in the main extensions of devices already familiar in educational psychology. The more important are: (i) where the criterion yields a threefold classification only, a method of triserial correlation or of biserial correlation assuming point-distributions for the extremes; (ii) where the data on which validation has to be based are drawn from a selected sample, a simplified form of Pearson's equations to correct for selection; (iii) where the best line of demarcation has to be deduced from theoretical rather than practical considerations, a formula based on the principle of minimal discrepancy.     

Factor analysis and physical types

Physical measurements, obtained from several different age-groups and national groups, have been correlated and factorized. The largest of the investigations was based on 2,400 British airmen in the R.A.F., and the most recent included as many as 17 traits. The methods of factorization employed were those worked out in early investigations of mental and scholastic tests, and differed in minor respects from those more recently used by Thurstone in his re-analysis of some of our data. The factor patterns reveal a remarkable constancy from age to age and from one national group to another. The general factor accounts for about the same proportion of the variance as the general factor in cognitive tests. The largest of the bipolar factors classifies traits into longitudinal and transverse, thus in some measure confirming the traditional classification of body-types.     

Associative priming in perceptual identification: Effects of prime-processing requirements

Three experiments assessed the effects of prime-processing instructions on associative-priming in word identification and episodic memory for primes. In Experiment 1, groups instructed to read the prime silently or generate silently an associate of the prime showed a larger accuracy benefit for related over unrelated targets than did a group that decided whether an asterisk was to the right or left of the prime. The asterisk-search group showed a weaker repetition effect on a subsequent identification test of primes, indicating that the weaker priming in this group was a result of poorer perceptual processing. On a cued-recall test for primes, the generate group was superior to the other groups. In Experiment 2, we found that with weak prime-target associations, priming was comparable for read and generate groups and stronger than estimated for a guessing strategy, on the basis of single predictions made from each prime by an additional group. In Experiment 3, we demonstrated that the read and generate instructions produced similar mispriming and inhibitory effects. The results suggest that the depths of prime-processing manipulations do not have parallel effects on priming and episodic memory, and that associative priming in word identification, as in other tasks, may involve an expectancy process.     

The effect of actual event duration and event memory on the reconstruction of duration information

Two experiments investigated the effect of actual event duration and event memory on the retrospective estimation of public event duration. Experiment 1 provided a typicality score for each of 20 public events. The typicality score represents the degree to which the event's actual duration deviates from the typical duration of its category. Subjects in Experiment 2 estimated the duration of the events used in Experiment 1 and indicated whether they remembered the events. Typicality scores were found to be highly correlated with estimation accuracy, and to predict whether event duration was under- or over-estimated. Remembering an event slightly increased estimation accuracy. The results are discussed in terms of their implications for the assessment of eyewitness retrospective duration estimation abilities, and the reconstructive model of retrospective duration estimation proposed by Burt and Kemp (1991).     

Exploration of the Factor Structure of ADHD in Adolescence through Self,Parent, and Teacher Reports of Symptomatology

Factor analytic studies of attention-deficit/hyperactivity disorder (ADHD) in children and adults have shown that second-order and bifactor models better represent ADHD symptoms than two- or three-factor models, yet there is far less evidence for a bestfitting model of ADHD in adolescence. Thus, the current study examined the factor structure of ADHD in adolescence and further evaluated the external validity of the best fitting model. Participants were 588 adolescents (22 % female; 366 with a childhood ADHD diagnosis; mean age 15.9 years) from the 8-year assessment of the Multimodal Treatment Study of Children with ADHD (MTA). ADHD symptoms were assessed via adolescent self-report, parent report, and teacher report on the SNAP-IV scale. Potential factor structures for the 18 symptoms of ADHD were tested for each informant, which included traditional one-factor, two-factor, and three-factor models of ADHD, as well as second-order factor (specific factors loading onto general factor) and bifactor (items loading onto both specific and general factors) models. Unique associations between external criteria and the identified factors of each informant’s best fitting model were examined. Although several of the proposed models exhibited good fit, the second-order two-factor model best accounted for ADHD in adolescence according to self-report and parent report, and the second-order three-factor model was optimal according to teacher report. Several key measurement issues emerged for the hierarchical bifactor models, such as numerous Heywood cases and out-of-bound parameter estimates, which rendered them unfit as optimal representations of ADHD in adolescence. These findings and the implications of the best fitting model of ADHD in adolescence suggest that a possible reorganization of this disorder may eventually aid clinicians in the accurate diagnosis of ADHD in adolescents.     

Masked form priming is moderated by the size of the letter-order-free orthographic neighbourhood

University students made lexical decisions to targets preceded by masked primes. In Experiment 1, transposed-letter primes were used also in the sandwich priming paradigm, in which the target is briefly pre-presented prior to the prime. The priming effects in the masked paradigm, but not in the sandwich paradigm, were moderated by the density of the letter-order-free neighbourhood of the target. In Experiment 2, letter-order-free neighbour prime words produced a priming cost in masked priming. These results are consistent with the idea that sandwich priming attenuates letter-order-free neighbour competition in target identification. Unexpectedly, no priming cost was produced by conventional (letter-position-preserving) word neighbour primes. Order-free neighbours may produce facilitation of target processing less, and more variably, than conventional neighbours.     

Orthographic influences in spoken word recognition: The consistency effect in semantic and gender categorization tasks

According to current models, spoken word recognition is driven by the phonological properties of the speech signal. However, several studies have suggested that orthographic information also influences recognition in adult listeners. In particular, it has been repeatedly shown that, in the lexical decision task, words that include rimes with inconsistent spellings (e.g., /-ip/ spelled -eap or -eep) are disadvantaged, as compared with words with consistent rime spelling. In the present study, we explored whether the orthographic consistency effect extends to tasks requiring people to process words beyond simple lexical access. Two different tasks were used: semantic and gender categorization. Both tasks produced reliable consistency effects. The data are discussed as suggesting that orthographic codes are activated during word recognition, or that the organization of phonological representations of words is affected by orthography during literacy acquisition.     

Parent and Adolescent Gender Role Attitudes in 1990s Great Britain

Using data from the British Household Panel Survey, this short-term longitudinal study examined relationships between early- and mid-adolescents' gender role attitudes and the attitudes of their parents. Between 1994 and 1997, 602 families answered questions about the roles of husbands and wives, and whether or not having a working mother is harmful to families. Results confirmed that the gender differences that have been found consistently in the literature regarding adults extend back into early adolescence. Adolescent girls' attitudes were markedly more nontraditional than all other family members. However, results only partially supported our hypotheses regarding family influence on attitudes. In particular, we found little evidence that adolescent attitudes would more closely resemble those of the same-gender parent. Analysis of individual questions supports arguments that gender roles are complex and socially determined, and that British men of both adult and adolescent generations have begun in principle to accept nontraditional roles for wives but are less willing to support any erosion of male power in the family.