Reference in single sentences and in texts

This study investigated the comprehension and production of reference terms in both sentences (Experiments 1 and 2) and texts (Experiments 3 and 4) using a sentence completion task. In Experiments 1 and 2, the use of a sentence-level strategy (subject assignment) was investigated. In Experiments 3 and 4, the use of a text-level strategy (topic assignment) was also investigated. There was a clear preference for continuing the sentences by referring to the subjects of the sentences regardless of the availability of gender cues, in both single sentences and in texts. There was also an influence of the topic of each text on both the choice of referent and the type of reference term used. However, the choice of reference term was affected by the number of potential antecedents in the preceding text. Overall, the results suggest that the sentence subject is a salient item in working memory. This salience is increased if the sentence subject is also the textual topic. In addition, it appears that the presence of a pronoun in a text triggers a specific strategy to assign the pronoun to the (salient) sentence subject.This work is based on a doctoral dissertation submitted by R. A. Crawley to the University of Durham and supported by the Medical Research Council of Great Britain.     

The use of heuristic strategies in the interpretation of pronouns

The aim of the two experiments reported here was to distinguish between two heuristic strategies that have been proposed to account for the assignment of pronouns: the subject assignment strategy and the parallel function strategy. According to the subject assignment strategy, a pronoun is assigned to a preceding subject noun phrase, whereas according to the parallel function strategy, a pronoun is assigned to a previous noun phrase in the same grammatical position as the pronoun. These two strategies were tested by examining the interpretation of single object pronouns, first in a reading task and second in an assignment task. In both experiments, there was a strong preference for assigning an object pronoun to the preceding subject noun phrase, thus supporting the subject assignment strategy. However, this was only the case for pronouns that were linguistically ambiguous. When assignment was constrained by gender, there was no effect of either strategy. It is suggested that heuristic strategies are only used in the absence of other strong cues to assignment.     

When did Mrs Thatcher resign? The effects of ageing on the dating of public events

Two experiments investigated whether, in light of the commonly reported phenomenon of subjective time acceleration with age, there would be an effect of age on the dating of public events. In the first experiment covering the past seven years there was the suggestion of a decrease in forward telescoping with age, and in the second covering the period from 1977-89 this trend was continued, with the over-60s group now showing a tendency to date events too distantly. This effect is uncommon in dating studies and may offer evidence for the existence of time acceleration. An additional finding was that adults in the age range 35-50 years showed greater accuracy in dating events than did university students and adults over the age of 60.     

The hoarding dimension of OCD: psychological comorbidity and the five-factor personality model

Although hoarding has been associated with several psychological disorders, it is most frequently linked to obsessive-compulsive disorder (OCD). The present study assessed hoarding obsessions and compulsions in 204 individuals with OCD, and evaluated how hoarding was related to obsessive-compulsive symptom severity, psychological comorbidity, and personality as measured by the five-factor model. Results indicated that hoarding in OCD is a dimensional variable that is positively associated with dysphoria, total number of lifetime Axis I disorders, and lifetime histories of bipolar I, PTSD, and body dysmorphic disorder. Hoarding was negatively correlated with the NEO-Personality Inventory-Revised (NEO-PI-R) factor of Conscientiousness and positively associated with the NEO-PI-R factor of Neuroticism. When all personality and psychopathology variables were entered into a regression equation, dysphoria, bipolar II disorder, Conscientiousness, age, and Extraversion emerged as significant predictors of hoarding severity. Recommendations are made for clinicians and for future research.     

Field and observer viewpoint in remember-know memories of personal childhood events

This experiment examined the viewpoint and other phenomenal characteristics of childhood memories based on both personal recollections and self-knowledge. Participants were asked to provide examples of remember, know, and uncertain memories, and to rate each memory on a number of dimensions. Remembered events were generally viewed from a field perspective, while known-about events were generally viewed from an observer perspective. In line with earlier research, remembered events received the highest ratings for sensory and contextual detail, emotional content, and memory accuracy, while known-about events were given the lowest ratings. The results are discussed with reference to their possible implications for memory recovery or enhancement techniques that ask people to adopt a different viewpoint. Consideration is given as to whether a switch to a field perspective might encourage the acceptance of suggested details or events.     

Hyperactivity and Learning Deficits in Transgenic Mice Bearing a Human Mutant Thyroid Hormone β1 Receptor Gene

Resistance to thyroid hormone (RTH) is a human syndrome mapped to the thyroid receptor β (TRβ) gene on chromosome 3, representing a mutation of the ligandbinding domain of the TRβ gene. The syndrome is characterized by reduced tissue responsiveness to thyroid hormone and elevated serum levels of thyroid hormones. A common behavioral phenotype associated with RTH is attention deficit hyperactivity disorder (ADHD). To test the hypothesis that RTH produces attention deficits and/or hyperactivity, transgenic mice expressing a mutant TRβ gene were generated. The present experiment tested RTH transgenic mice from the PV kindred on behavioral tasks relevant to the primary features of ADHD: hyperactivity, sustained attention (vigilance), learning, and impulsivity. Male transgenic mice showed elevated locomotor activity in an open field compared to male wild-type littermate controls. Both male and female transgenic mice exhibited impaired learning of an autoshaping task, compared to wild-type controls. On a vigilance task in an operant chamber, there were no differences between transgenics and controls on the proportion of hits, response latency, or duration of stimulus tolerated. On an operant go/no-go task measuring sustained attention and impulsivity, there were no differences between controls and transgenics. These results indicate that transgenic mice bearing a mutant human TRβ gene demonstrate several behavioral characteristics of ADHD and may serve a valuable heuristic role in elucidating possible candidate genes in converging pathways for other causes of ADHD.     

Closure of autobiographical memories: The effects of written recounting from first- or third-person visual perspective

Autobiographical memories are recalled with varying degrees of psychological closure. Closure is a subjective assessment of how far a remembered experience feels resolved, and it has been suggested that one predictor of closure is the amount of emotional detail in the memory. Study 1 examined which aspect of emotional detail is important for closure, and showed that open and closed negative memories were distinguished by ratings of emotion evoked during recall, not by remembered emotion from the time of the event. The recall of open memories was accompanied by more intense, more negative, and less positive emotion than the recall of closed memories. Biased retelling of memories has been shown to influence closure and on the basis of evidence that third-person recall serves a distancing function, Study 2 examined whether instructions to repeatedly recount an open memory from a third-person perspective would increase closure compared with a single or repeated recounting from a first-person perspective. While repeated third-person recounting had the greatest influence on closure, there were also increases in the first-person recounting groups. The results suggest that closure can be increased by reporting memories in written narrative form, particularly if repeatedly expressed from the third-person perspective.     

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.