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Over the last two decades, the multi-dimensional notion of job performance has been fully brought to life. The differentiation between core task performance and various aspects of discretionary work behaviour is flow commonly applied. A multitude of empirical studies, enhancing our knowledge of the antecedents and consequences of the different performance aspects, have recently been summarised through various meta-analyses. We use this as all occasion for taking stock in order to identify new areas of theorising and empirical research. Focusing in particular oil proactive performance aspects, the present paper identifies three themes that could inspire new research and model development. We suggest taking a new approach to the treatment of time in order to account for the dynamic nature of performance oil the one hand, and to consider life-span changes oil the other, developing comprehensive models oil proactivity-enhancing interventions, and more strongly incorporating a cross-cultural perspective.
In reading, word frequency is commonly regarded as the major bottom-up determinant for the speed of lexical access. Moreover, language processing depends on top-down information, such as the predictability of a word from a previous context. Yet, however, the exact role of top-down predictions in visual word recognition is poorly understood: They may rapidly affect lexical processes, or alternatively, influence only late post-lexical stages. To add evidence about the nature of top-down processes and their relation to bottom-up information in the timeline of word recognition, we examined influences of frequency and predictability on event-related potentials (ERPs) in several sentence reading studies. The results were related to eye movements from natural reading as well as to models of word recognition. As a first and major finding, interactions of frequency and predictability on ERP amplitudes consistently revealed top-down influences on lexical levels of word processing (Chapters 2 and 4). Second, frequency and predictability mediated relations between N400 amplitudes and fixation durations, pointing to their sensitivity to a common stage of word recognition; further, larger N400 amplitudes entailed longer fixation durations on the next word, a result providing evidence for ongoing processing beyond a fixation (Chapter 3). Third, influences of presentation rate on ERP frequency and predictability effects demonstrated that the time available for word processing critically co-determines the course of bottom-up and top-down influences (Chapter 4). Fourth, at a near-normal reading speed, an early predictability effect suggested the rapid comparison of top-down hypotheses with the actual visual input (Chapter 5). The present results are compatible with interactive models of word recognition assuming that early lexical processes depend on the concerted impact of bottom-up and top-down information. We offered a framework that reconciles the findings on a timeline of word recognition taking into account influences of frequency, predictability, and presentation rate (Chapter 4).
Stress is known to induce cigarette craving in smokers, but the underlying mechanisms are widely unknown. We investigated how dependence severity, smoking habits and stress-induced cortisol secretion are associated with increased cigarette craving after a standardised laboratory stressor. Hundred and six healthy participants (50 men, age 18-19 years) underwent a standardised public speaking stress task. In all, 35 smoked daily (DS), 13 smoked occasionally (OS), and 58 never smoked (NS). Smoking was unrestricted until 2 h before stress onset. Plasma cortisol was measured before and up to 95 min after the stressor. All current smokers rated intensity of cigarette craving immediately before and immediately after the stressor using the Brief Questionnaire of Smoking Urges (BQSU). Cortisol levels significantly increased in response to stress in all groups. The magnitude of this stress response was significantly lower in DS compared with OS and NS but did not differ between OS and NS. Baseline BQSU scores were significantly higher in DS than OS. BQSU scores increased significantly during the stress period and were positively correlated to the cortisol response in the DS but were unrelated to their nicotine dependence scores. In OS, no change in cigarette craving could be observed. In daily smokers, cigarette craving is increased after compared with before stress exposure and is related to the magnitude of cortisol stress response rather than to severity of nicotine dependence. This result supports, but does not prove, the concept that hypothalamus-pituitary-adrenal stimulation is one of the mechanisms how stress can elicit cigarette craving.
Comparing continuous and discrete birthday coincidences : "Same-Day" versus "Within 24 Hours"
(2010)
In its classical form the famous birthday problem (Feller 1968; Mosteller 1987) addresses coincidences within a discrete sample space, looking at births that fall on the same calendar day. However, coincidence phenomena often arise in situations in which it is more natural to consider a continuous-time parameter. We first describe an elementary variant of the classical problem in continuous time, and then derive and illustrate close approximate relations that exist between the discrete and the continuous formulations.
Objectives: This study investigated the psychological as well as neuroendocrine stress response across one week before an important sport competition, introducing the cortisol awakening response (CAR) to sport psychological research. Methods: On three days in the week before the German Nationals, martial artists (N = 17) reported their competitive state anxiety and collected five samples of salivary cortisol during the first hour after awakening. Results: Hierarchic-linear models and multiple regressions were conducted. Despite a significant rise in "somatic anxiety" (p < .05), the increment of CAR across the week remained non-significant. A moderator function of competitive anxiety on the released amount of cortisol in the morning was not found significant. Results did not show any significant regression of changes in the neuroendocrine response on changes in state anxiety. Conclusion: Non- significant increments of CAR with a closer proximity to the competition may be interpreted as a possible habituation of basal hypothalamus-pituitary-adrenal activity. Moreover, athletes appear to have a lower CAR than found in norm studies, which points to further investigation of interindividual and situational effects on the temporal pattern of the neuroendocrine response to sport competitions.
Eye-movement control during scene viewing can be represented as a series of individual decisions about where and when to move the eyes. While substantial behavioral and computational research has been devoted to investigating the placement of fixations in scenes, relatively little is known about the mechanisms that control fixation durations. Here, we propose a computational model (CRISP) that accounts for saccade timing and programming and thus for variations in fixation durations in scene viewing. First, timing signals are modeled as continuous-time random walks. Second, difficulties at the level of visual and cognitive processing can inhibit and thus modulate saccade timing. Inhibition generates moment-by-moment changes in the random walk's transition rate and processing-related saccade cancellation. Third, saccade programming is completed in 2 stages: an initial, labile stage that is subject to cancellation and a subsequent, nonlabile stage. Several simulation studies tested the model's adequacy and generality. An initial simulation study explored the role of cognitive factors in scene viewing by examining how fixation durations differed under different viewing task instructions. Additional simulations investigated the degree to which fixation durations were under direct moment-to-moment control of the current visual scene. The present work further supports the conclusion that fixation durations, to a certain degree, reflect perceptual and cognitive activity in scene viewing. Computational model simulations contribute to an understanding of the underlying processes of gaze control.
One of the earliest categorical distinctions to be made by preverbal infants is the animate-inanimate distinction. To explore the neural basis for this distinction in 7-8-month-olds, an equal number of animal and furniture pictures was presented in an ERP-paradigm. The total of 118 pictures, all looking different from each other, were presented in a semi-randomized order for 1000 ms each. Infants' brain responses to exemplars from both categories differed systematically regarding the negative central component (Nc: 400-600 ms) at anterior channels. More specifically, the Nc was enhanced for animals in one subgroup of infants, and for furniture items in another subgroup of infants. Explorative analyses related to categorical priming further revealed category-specific differences in brain responses in the late time window (650-1550 ms) at right frontal channels: Unprimed stimuli (preceded by a different-category item) elicited a more positive response as compared to primed stimuli (preceded by a same-category item). In sum, these findings suggest that the infant's brain discriminates exemplars from both global domains. Given the design of our task, we conclude that processes of category identification are more likely to account for our findings than processes of on-line category formation during the experimental session.
Background: Recent animal and human studies indicate that the exposure to alcohol during early adolescence increases the risk for heavy alcohol use in response to stress. The purpose of this study was to examine whether this effect may be the consequence of a higher susceptibility to develop "drinking to cope" motives among early initiators. Methods: Data from 320 participants were collected as part of the Mannheim Study of Children at Risk, an ongoing epidemiological cohort study. Structured interviews at age 15 and 19 were used to assess age at first alcohol experience and drunkenness. The young adults completed questionnaires to obtain information about the occurrence of stressful life events during the past 4 years and current drinking habits. In addition, alcohol use under conditions of negative states was assessed with the Inventory of Drinking Situations. Results: The probability of young adults' alcohol use in situations characterized by unpleasant emotions was significantly increased the earlier they had initiated the use of alcohol, even when controlling for current drinking habits and stressful life events. Similar results were obtained for the age at first drunkenness. Conclusions: The findings strengthen the hypothesis that alcohol experiences during early adolescence facilitate drinking to regulate negative affect as an adverse coping strategy which may represent the starting point of a vicious circle comprising drinking to relieve stress and increased stress as a consequence of drinking.
Memory sets of N=1 ~ 5 digits were exposed sequentially from left-to-right across the screen, followed by N recognition probes. Probes had to be compared to memory list items on identity only (Sternberg task) or conditional on list position. Positions were probed randomly or in left-to-right order. Search functions related probe response times to set size. Random probing led to ramped, "Sternbergian" functions whose intercepts were elevated by the location requirement. Sequential probing led to flat search functionsùfast responses unaffected by set size. These results suggested that items in STM could be accessed either by a slow search-on-identity followed by recovery of an associated location tag, or in a single step by following item-to-item links in study order. It is argued that this dual coding of location information occurs spontaneously at study, and that either code can be utilised at retrieval depending on test demands.
Objective: We investigated in a high-risk sample the differential impact of biological and psychosocial risk factors on antisocial behaviour pathways. Method: One hundred and thirty-eight boys and 155 girls born at differing degrees of obstetric and psychosocial risk were examined from birth until adolescence. Childhood temperament was assessed by a highly-structured parent-interview and standardized behavioural observations, adolescent temperament was measured by self-report. Neurodevelopmental variables were assessed by age-specific developmental tests. Emotional and behaviour problems were measured at the ages of 8 and 15 by the Achenbach scales. Results: In both genders, psychosocial adversity and early self-control temperament were strongly associated with early-onset persistent (EOP) antisocial behaviour. Psychosocial adversity and more severe externalizing problems differentiated the EOP from childhood-limited (CL) pathway. In girls, adolescent-onset (AO) antisocial behaviour was strongly associated with novelty seeking at 15 years. Conclusion: Our findings emphasize the need for early support and intervention in psychosocially disadvantaged families.