Investigating systematic individual differences in sleep-deprived performance on a high-fidelity flight simulator

Laboratory research has revealed considerable systematic variability in the degree to which individuals' alertness and performance are affected by sleep deprivation. However, little is known about whether or not different populations exhibit similar levels of individual variability. In the present study, we examined individual variability in performance impairment due to sleep loss in a highly select population of militaryjet pilots. Ten active-duty F-117 pilots were deprived of sleep for 38 h and studied repeatedly in a high-fidelity flight simulator. Data were analyzed with a mixed-model ANOVA to quantify individual variability. Statistically significant, systematic individual differences in the effects of sleep deprivation were observed, even when baseline differences were accounted for. The findings suggest that highly select populations may exhibit individual differences in vulnerability to performance impairment from sleep loss just as the general population does. Thus, the scientific and operational communities' reliance on group data as opposed to individual data may entail substantial misestimation of the impact of job-related stressors on safety and performance.     

Trauma and autobiographical memory specificity in depressed inpatients

Research on autobiographical memory has shown that clinical depression is associated with a difficulty in retrieving specific autobiographical memories in response to cue words. This study examined the relation between lack of autobiographical memory specificity and self-reported trauma in a group of depressed adults (N = 23). In addition to the Autobiographical Memory Test (AMT; Williams & Broadbent, 1986) participants completed a number of questionnaires assessing the presence of traumatic experiences in the past, level of depression and neuroticism. The number of specific responses was not related to depression severity, but was significantly associated with the presence and severity of reported physical abuse. Participants who had been victim of physical abuse were less specific than participants who had not been confronted with such physical adversities. The results are discussed in the context of a functional hypothesis about the developmental relations between memory specificity, trauma and depression.     

Inhibition and shifting in children with learning deficits in arithmetic and reading

The executive functions of inhibition and shifting were studied in arithmetic-disabled children, reading-disabled children, reading plus arithmetic-disabled children, and controls (N = 74). Measures involved the rapid naming of objects, digits, letters, or quantities with or without additional task requirements that reflected inhibition or shifting. Also, the Making Trails task, reflecting shifting, was administered. For tasks without executive demands, arithmetic-disabled children were slower in the naming of digits and quantities, whereas reading-disabled children were slower in the naming of digits and letters. For the executive tasks, arithmetic-disabled children as well as reading plus arithmetic-disabled children were impaired on the Making Trails task and on an object naming task that required both inhibition and shifting. Reading-disabled children exhibited no problems in executive functioning. Furthermore, it was shown that reading plus arithmetic-disabled children experienced the combination of problems that characterize children with a single learning deficit.     

Openness to experience and boundaries in the mind: relationships with cultural and economic conservative beliefs

The present research investigates whether Openness to Experience and Boundaries in the mind are related to conservatism. In the first study, significant relationships between several scales of the Boundaries in the mind questionnaire and indicators of conservative beliefs were obtained in an adult sample (N=78) as well as in a sample of political party activists (N=44). In the second study, these negative relationships between conservatism and thin boundaries were replicated in an adult sample (N=225). Moreover, two dimensions representing Boundaries in the mind were identified, one positively related to Openness to Experience and negatively to conservatism and the second showing high positive correlations with Neuroticism. The exceptionally strong correlations between conservatism and the Boundaries in the mind facet scales Opinions about organizations, Opinions about beauty, truth, Edges, lines, clothing and Opinions about peoples, nations, groups are discussed, as well as the weak relationships between economic conservatism and Openness to Experience.     

Autobiographical memory in middle childhood: recollections of the recent and distant past

To address the question of whether memories from early childhood survive into later childhood, participants visited the laboratory at age 3 and again at 7, 8, or 9. At age 3, each talked with a parent about six events; at the later age each child talked with a researcher about four of these distant events as well as two more recent events. School-aged children recalled fewer than half of the distant events introduced. Further, the proportion of distant events recalled was negatively correlated with age. Those distant events that were recalled, however, were recounted in an accurate, detailed manner. Importantly, reports of distant events did not reflect the full extent of children's narrative ability. Reports of recent events were more coherent and included twice the detail. Implications for existing interpretations of autobiographical memory and childhood amnesia are discussed, and the need for further research employing innovative methods is emphasised.     

Anticipating upcoming words in discourse: evidence from ERPs and reading times

The authors examined whether people can use their knowledge of the wider discourse rapidly enough to anticipate specific upcoming words as a sentence is unfolding. In an event-related brain potential (ERP) experiment, subjects heard Dutch stories that supported the prediction of a specific noun. To probe whether this noun was anticipated at a preceding indefinite article, stories were continued with a gender-marked adjective whose suffix mismatched the upcoming noun's syntactic gender. Prediction-inconsistent adjectives elicited a differential ERP effect, which disappeared in a no-discourse control experiment. Furthermore, in self-paced reading, prediction-inconsistent adjectives slowed readers down before the noun. These findings suggest that people can indeed predict upcoming words in fluent discourse and, moreover, that these predicted words can immediately begin to participate in incremental parsing operations.     

Speech disruption under delayed auditory feedback in multilingual speakers

The present study investigated the language familiarity hypothesis formulated by Mackay [(1970). How does language familiarity influence stuttering under delayed auditory feedback? Perceptual and Motor Skills, 30, 655-669] that bilinguals speak faster and stutter less under delayed auditory feedback (DAF) when speaking their more familiar language than a less familiar language. Thirty normally fluent native speakers of Dutch (17 males and 13 females, aged between 18;1 and 26;4 years) who were also proficient in French and English read meaningful and nonsense text under DAF in their mother tongue and in the two later acquired languages. The existence of a language familiarity effect was confirmed. The participants required significantly more time and showed significantly more speech disruptions under DAF in the later acquired languages than in the mother tongue, and reading time and number of speech disruptions was significantly higher for the nonsense texts than for the meaningful text for each of the three languages. An additional question addressed was whether or not there were any gender differences in the susceptibility to DAF. Results did not reveal a clear gender difference. EDUCATIONAL OBJECTIVES: The reader will be able to: (1) summarize the importance of language familiarity for the degree of speech disruption experienced by normally fluent multilingual speakers under delayed auditory feedback; and (2) describe gender differences in the susceptibility to delayed auditory feedback.     

Relationships of Functional Flexibility with Individual and Work Factors

To investigate how functional flexibility is related to demographics, personality traits, and work perceptions, 250 employees of a large Dutch passenger transport firm filled out a written questionnaire. Two dimensions of functional flexibility were discerned: willingness and ability to be flexible. Analysis of variance showed the support staff and managers were higher on willingness and ability to be flexible than workers. Hierarchic regression analysis showed that willingness to be flexible was positively related to initiative and trust in management, and was negatively related to age and task formalization. Ability to be flexible was positively related to general self-efficacy and initiative, and was negatively related to task formalization. It was concluded that willingness to be flexible depends on fair treatment and freedom provided by their organization and that ability to be flexible is part of the development of general self-efficacy.