The interim test effect: Testing prior material can facilitate the learning of new material

A wealth of prior research has shown that testing can improve subsequent learning of the initially tested material. In contrast, only one recent study has shown that an interim test over prior material can improve learning of subsequent new material (i.e., an interim-test effect). Five experiments replicated and extended this initial work by exploring the extent to which interim test effects generalize to complex text material. Participants were prompted to recall each section of an expository text before moving on to study the next section, or were only prompted to recall after the final section. In all experiments, recall of the final, target section was greater when prior sections had received interim tests versus no interim tests. Experiment 3 established that the effect was due to interim testing in particular rather than to intervening activity in general. Experiment 4 established that the effect was not due to test expectancy differences. In contrast to prior research, Experiment 4 also provided evidence that the effect is not due to release from proactive interference. We discuss other possible mechanisms underlying interim-test effects with text, including shifting to more effective encoding strategies.     

Working memory deficits, increased anxiety-like traits, and seizure susceptibility in BDNF overexpressing mice

BDNF regulates components of cognitive processes and has been implicated in psychiatric disorders. Here we report that genetic overexpression of the BDNF mature isoform (BDNF-tg) in female mice impaired working memory functions while sparing components of fear conditioning. BDNF-tg mice also displayed reduced breeding efficiency, higher anxiety-like scores, high self-grooming, impaired prepulse inhibition, and higher susceptibility to seizures when placed in a new empty cage, as compared with wild-type (WT) littermate controls. Control measures of general health, locomotor activity, motor coordination, depression-related behaviors, and sociability did not differ between genotypes. The present findings, indicating detrimental effects of life-long increased BDNF in mice, may inform human studies evaluating the role of BDNF functional genetic variations on cognitive abilities and vulnerability to psychiatric disorders.     

Plasticity associated with escalated operant ethanol self-administration during acute withdrawal in ethanol-dependent rats requires intact matrix metalloproteinase systems

Repeated cycles of ethanol intoxication and withdrawal associated with dependence induce neuroadaptations in a variety of brain systems. Withdrawal-induced negative emotional states can be ameliorated by ethanol consumption; a learned process termed negative reinforcement. Accordingly, a dependence-induced phenotype is escalated ethanol self-administration. Matrix metalloproteinases (MMPs) are proteolytic enzymes which degrade the extracellular matrix to allow for synaptic reorganization and plasticity. To test the hypothesis that an intact MMP system is required for animals to learn about the negative reinforcing effects of ethanol and display escalated self-administration during acute withdrawal when ethanol-dependent, male Wistar rats were trained to self-administer ethanol and then assigned to either acute or chronic MMP inhibition treatment groups. The chronic treatment group received intracerebroventricular (ICV) infusions of the broad spectrum MMP inhibitor FN-439 or artificial cerebrospinal fluid (aCSF) via osmotic minipumps during a 1 month ethanol dependence induction period and subsequent post-dependence induction self-administration sessions that occurred during acute withdrawal. The acute treatment group only received ICV FN-439 or aCSF on the day of self-administration sessions following dependence induction during acute withdrawal. The results showed that inhibition of MMPs attenuated escalated ethanol self-administration following chronic and acute exposure conditions. Furthermore, once learning (i.e., plasticity) had occurred, MMP inhibition had no impact on escalated response patterns and animals previously subjected to MMP inhibition that did not escalate evidenced normal escalations in operant ethanol self-administration once FN-439 treatments were terminated. Thus, the present data identified that an intact MMP system is required for the escalated responding that occurs during acute withdrawal in dependent animals and implicate such escalation as a learned response.     

Psychometric adequacy and comparability of the short and full forms of the Personality Assessment Inventory

The 160-item short form of the Personality Assessment Inventory (PAI) was developed for situations in which respondents complete only the 1st half of the test. The present study evaluates the adequacy and comparability of the full and short forms of the PAI in terms of a wide range of psychometric characteristics. In all, 421 participants completed the full form as part of a neuropsychological evaluation. Results indicated slightly lower internal consistency reliability of the short compared with the full form. Group-level agreement of short and full form scales ranged from adequate to excellent. However, within-subject agreement was somewhat more variable. Low levels of within-subject agreement were strongly associated with elevated validity scale scores. The factor structures of the full and short forms showed high congruence for a 3-factor solution. These findings suggest that many scales of the short form have adequate comparability with their respective full form scales. However, low levels of reliability across less impaired ranges of the latent trait, diminished content coverage, and altered validity detection may limit the utility of some of the short form scales.     

Harm, intent, and the nature of aggressive behavior: measuring naturally occurring aggression in barroom settings

The research goals were to use the constructs of harm and intent to quantify the severity of aggression in the real-world setting of the bar/club, to describe the range of aggressive behaviors and their relationship to harm and intent, and to examine gender differences in the form and severity of aggression. Systematic observations were conducted by trained observers on 1,334 nights in 118 bars/clubs. Observers documented a range of aggressive acts by 1,754 patrons in 1,052 incidents, with many forms of aggression occurring at more than one harm and intent level. Women used different forms of aggression, inflicted less harm, and were more likely to have defensive intent compared with men. Implications of the findings for research and measurement of aggression and applications to preventing aggression and violence are discussed.     

A metric for the cognitive map: found at last?

A network of brain areas collectively represent location, but the underlying nature of this "cognitive map" has remained elusive. A recent study reports that the activity patterns of some entorhinal cortical neurons form a remarkably regular array of evenly spaced peaks across the surface of the environment. These "grid cells" might be the basis of a metric used for calculating position, and their discovery could greatly advance our understanding of how navigational computations are performed.     

Birthweight-discordance and differences in early parenting relate to monozygotic twin differences in behaviour problems and academic achievement at age 7

This longitudinal monozygotic (MZ) twin differences study explored associations between birthweight and early family environment and teacher-rated behaviour problems and academic achievement at age 7. MZ differences in anxiety, hyperactivity, conduct problems, peer problems and academic achievement correlated significantly with MZ differences in birthweight and early family environment, showing effect sizes of up to 2%. As predicted by earlier research, associations increased at the extremes of discordance, even in a longitudinal, cross-rater design, with effect sizes reaching as high as 12%. As with previous research some of these non-shared environmental (NSE) relationships appeared to operate partly as a function of SES, family chaos and maternal depression. Higher-risk families generally showed stronger negative associations.     

Serial position effects in recognition memory for odors: A reexamination

Seven experiments examined recognition memory for sequentially presented odors. Following Reed (2000), participants were presented with a sequence of odors and then required to identify an odor from the sequence in a test probe comprising 2 odors. The pattern of results obtained by Reed (2000, although statistically marginal) demonstrated enhanced recognition for odors presented at the start (primacy) and end (recency) of the sequence: a result that we failed to replicate in any of the experiments reported here. Experiments 1 and 3 were designed to replicate Reed (2000), employing five-item and seven-item sequences, respectively, and each demonstrated significant recency, with evidence of primacy in Experiment 3 only. Experiment 2 replicated Experiment 1, with reduced interstimulus intervals, and produced a null effect of serial position. The ease with which the odors could be verbally labeled was manipulated in Experiments 4 and 5. Nameable odors produced a null effect of serial position (Experiment 4), and hard-to-name odors produced a pronounced recency effect (Experiment 5); nevertheless, overall rates of recognition were remarkably similar for the two experiments at around 70%. Articulatory suppression reduced recognition accuracy (Experiment 6), but recency was again present in the absence of primacy. Odor recognition performance was immune to the effects of an interleaved odor (Experiment 7), and, again, both primacy and recency effects were absent. There was no evidence of olfactory fatigue: Recognition accuracy improved across trials (Experiment 1). It is argued that the results of the experiments reported here are generally consistent with that body of work employing hard-to-name visual stimuli, where recency is obtained in the absence of primacy when the retention interval is short.     

Behavioral reputation: a cross-age perspective

This study examined the measurement of peer perceptions of behavioral reputation within the contexts of elementary, middle, and high school environments (Grades 2-12, N = 2,812) through the systematic evaluation of the psychometric properties of the Revised Class Play (A. S. Masten, P. Morison, & D. S. Pellegrini, 1985). Confirmatory factor analyses demonstrated that the data did not fit A. S. Masten et al.'s original 3-factor structure. Cross-loading of items and different patterns of association between subscales across age groups (elementary, middle, and high school) contributed to the overall poor fit. Exploratory factor analyses revealed an alternative 4-factor structure as a more reliable and valid means of assessing behavioral reputation regardless of the age of the peer group sampled. Both convergent and divergent patterns of associations emerged across developmental levels.