Refine
Has Fulltext
- no (61)
Year of publication
- 2009 (61) (remove)
Document Type
- Article (61) (remove)
Is part of the Bibliography
- yes (61)
Institute
- Department Psychologie (61) (remove)
We compared individual-participant and jackknife-based methods for scoring the onset latencies of event-related potential (ERP) components using a diffusion process as a model for an ERP. We studied "ramp-like" components in which the true ERP increases or decreases monotonically, except for noise. If the growth rates of such components vary across participants, the jackknife-based measure can easily have only 10%-20% as much error variance as the traditional method, and this advantage is magnified with more participants. We also studied boolean AND-shaped or "bump-like" components. Jackknifing generally yielded smaller error variances with these components too, especially when the component's peak amplitude varied across participants, but less so if the component's peak latency varied. These results help illuminate the reasons for the superiority of jackknife-based onset latency measures over traditional measures in recent simulations.
Three experiments investigated proactive interference and proactive facilitation in a memory-updating paradigm. Participants remembered several letters or spatial patterns, distinguished by their spatial positions, and updated them by new stimuli up to 20 times per trial. Self-paced updating times were shorter when an item previously remembered and then replaced reappeared in the same location than when it reappeared in a different location. This effect demonstrates residual memory for no-longer-relevant bindings of items to locations. The effect increased with the number of items to be remembered. With one exception, updating times did not increase, and recall of final values did not decrease, over successive updating steps, thus providing little evidence for proactive interference building up cumulatively.
Values are assumed to be relatively stable during adulthood. Yet, little research has examined value stability and change, and there are no studies on the structure of value change. On the basis of S. H. Schwartz's (1992) value theory, the authors propose that the structure of intraindividual value change mirrors the circumplexlike structure of values so that conflicting values change in opposite directions and compatible values change in the same direction. Four longitudinal studies, varying in life contexts, time gaps, populations, countries, languages, and value measures, supported the proposed structure of intraindividual value change. An increase in the importance of any one value is accompanied by slight increases in the importance of compatible values and by decreases in the importance of conflicting values. Thus, intraindividual changes in values are not chaotic, but occur in a way that maintains Schwartz's value structure. Furthermore, the greater the extent of life-changing events, the greater the value change found, whereas age was only a marginal negative predictor of value change when life events were taken into account. Implications for the structure of personality change are discussed.
R. Sekuler, P. Tynan, and E. Levinson (1973) found that when 2 characters are presented side-by-side with a short onset asynchrony, subjectively, they often appear in a "first-left, then-right" order. The authors of this article conducted 6 experiments in which observers judged the temporal order (TOJs) in which 2 digits were presented. They found a consistent TOJ benefit (larger d') when the numerically smaller digit was presented first, even though this semantic information was irrelevant to the task and unrelated to the correct response. They concluded that digits located to the left of the mental number line are transmitted faster to a central comparison stage, which represents an "internal counterpart" to the Sekuler et al. (1973) finding regarding external locations. A corresponding benefit is found for letters pairs (e.g., A-Z) and also for mixed digit-letter pairs (e.g., I-Z).
Recent evidence suggests that heterogeneity in the age at onset could explain the inconsistent findings of association studies relating the dopamine transporter (DAT1) gene with alcohol and nicotine consumption. The aim of this study was to examine interactions between two DAT1 polymorphisms and different initiation ages with regard to alcohol and tobacco consumption levels and dependence. Two hundred and ninety-one young adults (135 males, 156 females) participating in the Mannheim Study of Children at Risk were genotyped for the 40-bp variable number of tandem repeats (VNTR) and rs27072 polymorphisms of DAT1. Age at initiation was assessed at age 15 and 19 years. Information about current alcohol and tobacco consumption was obtained at age 19 years using self-report measures and structured interviews. Results suggest that age at onset of intensive consumption moderated the association of the DAT1 gene with early adult substance use and dependence, revealing a DAT1 effect only among individuals homozygous for the 10r allele of the 40-bp VNTR who had started daily smoking or being intoxicated early in life. Equally, carriers of the T allele of the rs27072 polymorphism reporting an early age at first intoxication showed higher current alcohol consumption at age 19 years. In contrast, no interaction between rs27072 and the age at first cigarette with regard to later smoking was observed. These findings provide evidence that the DAT1 gene interacts with an early heavy or regular drug exposure of the maturing adolescent brain to predict substance (ab)use in young adulthood. Further studies are required to confirm these findings.
The article reports an experiment testing whether the Hebb repetition effectthe gradual improvement of immediate serial recall when the same list is repeated several timesdepends on overt recall of the repeated lists. Previous reports which suggest that recall is critical confound the recall manipulation with retention interval. The present experiment orthogonally varies retention interval (0 or 9 s) and whether the list is to be recalled after the retention interval. Hebb repetition learning is assessed in a final test phase. A repetition effect was obtained in all four experimental conditions; it was larger for recalled than non-recalled lists, whereas retention interval had no effect. The results show that encoding is sufficient to generate cumulative long-term learning, which is strengthened by recall. Rehearsal, if it takes place in the retention interval at all, does not have the same effect on long-term learning as overt recall.
In a high-risk community sample, we examined the role of regulative temperament and emotionality as well as the extent of gender specificity in the development of externalizing problems. 151 boys and 157 girls born at differing degrees of obstetric and psychosocial risk were followed from birth into adolescence. In infancy and childhood, NYLS- derived temperamental characteristics were assessed by a highly structured parent interview and standardized behavioral observations. At age 15 years, externalizing problems were measured by the Child Behavior Checklist. As revealed by multiple linear regression and logistic regression, low regulative abilities predicted adolescent behavioral and attentional problems over and above obstetric and psychosocial risks. Gender specificity was found in the strength of the association rather than in the kind with a stronger long-term prediction from infant and toddler temperament in girls. Compared to regulative abilities, temperament factors describing aspects of mood and fear/withdrawal versus approach tendencies played a minor role in the development of externalizing problems. Findings are discussed in terms of gender-specific risk factors and possible differential developmental trajectories to subtypes of disruptive behavior.
Is a specific disorder of arithmetic skills as common as reading/spelling disorder?Background: Referring to the prevalence rates of learning disorders in the research literature, the numbers of mathematics disorder and reading/ spelling disorder are often reported to be identical. However, the correlation between intelligence level and reading/ spelling skills is much weaker than between intelligence and arithmetic skills. If the same definition criterion is applied to both disorders, a lower prevalence rate for mathematics disorder should be expected. Objective: Are there differences in the prevalence estimates for learning disorders depending on the definition criterion? Method: A large representative sample of German students (N = 1970) was used to review the hypothesis. Results: Depending on the definition criterion, we could show a prevalence range of mathematics disorder between 0.1% and 8.1% in the same sample. Using the same definition criterion for both learning disorders, there are two to three times as many students with reading/spelling disorder than those with mathematics disorder. Discussion: Whenever children with reading/spelling disorder are compared to children with mathematics disorder, the same definition criterion has to be applied.
There is growing evidence from the international literature that nonconsensual sexual interactions are widespread among adolescents and young adults. Following a brief review of this literature, two studies are reported that examined the prevalence and predictors of sexual aggression and sexual victimization among young people in Germany. In addition to the traditional focus on male perpetrators and female victims, evidence is presented on women's sexual aggression towards men and men's sexual victimization by women. Variables increasing the risk of sexual aggression and vulnerability for victimization include both biographical factors (e. g., childhood abuse) and situational variables (e. g., ambiguous communication of sexual intentions). Special consideration is given to the representation of risk factors in the "sexual scripts" for consensual sexual interactions that serve as guidelines for sexual behavior. The paper concludes with a brief discussion of the implications of the findings for prevention efforts.
Evidence for semantic preview benefit (PB) from parafoveal words has been elusive for reading alphabetic scripts such as English. Here we report semantic PB for noncompound characters in Chinese reading with the boundary paradigm. In addition, PBs for orthographic relatedness and, as a numeric trend, for phonological relatedness were obtained. Results are in agreement with other research suggesting that the Chinese writing system is based on a closer association between graphic form and meaning than is alphabetic script. We discuss implications for notions of serial attention shifts and parallel distributed processing of words during reading.
Prävention kindlichen übergewichts : elterliche Selbstwirksamkeit und Handlungsergebniserwartungen
(2009)
Adipositas ist ein ernstzunehmendes gesundheitliches Problem, welches das physische und psychosoziale Wohlbefinden von Kindern und deren Eltern beeintraechtigt und somit wirksamer praeventiver Ansaetze bedarf. Dabei ist es bedeutsam, welche Barrieren, Anreize und Selbstwirksamkeitserwartungen Eltern fuer oder gegen die Teilnahme an solchen Programmen entscheiden lassen. Ziel der Studie war es zu untersuchen, wie Muetter ihre Selbstwirksamkeits- und Handlungsergebniserwartungen beschreiben und inwieweit sich soziodemografische Aspekte auf diese Einschaetzungen auswirken. Insgesamt wurden 219 Muetter von Kindern im Alter von 3-6 Jahren befragt. Mehr als die Haelfte der befragten Muetter waren uebergewichtig bzw. adipoes sowie 12% der Kinder. Es ergaben sich weder fuer das Alter und das Geschlecht des Kindes noch fuer das Familieneinkommen Unterschiede in den Handlungsergebniserwartungen. Muetter mit geringerer Bildung nahmen weniger Anreize wahr und Muetter mit uebergewichtigen Kindern sahen weniger Barrieren fuer eine Programmteilnahme. uebergewichtige Muetter dagegen bewerteten die Barrieren und Anreize hoeher als normalgewichtige Muetter. Hinsichtlich der Selbstwirksamkeit ergaben sich ebenfalls Unterschiede bezueglich der Bildung und des Gewichts der Mutter sowie des Kindes. Im Vorfeld einer Intervention sollte ein Beratungsgespraech bezogen auf die muetterlichen Erwartungen stattfinden, um die Teilnahmebereitschaft und den Programmerfolg zu unterstuetzen.
On the relationship between interoceptive awareness and the attentional processing of visual stimuli
(2009)
Mental processes related to visceral activity have gained growing interest during the last few years. The following study is the first to investigate possible interactions between interoceptive awareness and measures of attentional performance. We tested the hypothesis whether interoceptive awareness is positively related to indices of selective and divided attentional performances. Using a heartbeat perception task, 29 healthy female participants were separated into two groups scoring either high or low in an interoceptive awareness task. Attentional performance was assessed by several tests including the 'd2 test of attention' and subtests from the 'TAP: Test Battery for Attentional Performance'. We observed a significantly better performance in selective and divided attention for participants with high interoceptive awareness. Our data suggests that interoceptive awareness is related to a better performance especially in tasks assessing selective and divided attention. We conclude 1) that perception of bodily states might be a crucial determinant for the processing of external, visual stimuli, 2) that the ability to perceive internal signals might be an indicator of self-focused attention, and 3) that bodily signals may use, at least in part, similar processing resources as signals from the attention system.
Active motor processes are present in many sensory systems to enhance perception. In the human visual system, miniature eye movements are produced involuntarily and unconsciously when we fixate a stationary target. These fixational eye movements represent self-generated noise which serves important perceptual functions. Here we investigate fixational eye movements under the influence of external noise. In a two-choice discrimination task, the target stimulus performed a random walk with varying noise intensity. We observe noise-enhanced discrimination of the target stimulus characterized by a U-shaped curve of manual response times as a function of the diffusion constant of the stimulus. Based on the experiments, we develop a stochastic information-accumulator model for stimulus discrimination in a noisy environment. Our results provide a new explanation for the constructive role of fixational eye movements in visual perception.
No age differences in complex memory search : older adults search as efficiently as younger adults
(2009)
In 2 experiments, the authors investigated age differences in memory search under 4 conditions: forward search, backward search, random search, and fixed irregular search. Both search slopes and serial position curves were investigated. Mixing conditions led to smaller age differences than blocking conditions, suggesting that younger adults have an advantage over older adults when strategies can be applied to memory scanning. All age differences in scanning rates, however, disappeared when age differences in a magnitude-judgment control task were controlled for, showing that age differences in memory scanning tasks are not because of the scanning process per se, but because of attention, sensorimotor speed, and decision processes. In both experiments, the serial position curves of older adults echoed those of younger adults closely, demonstrating that younger and older adults use the same scanning processes.
Multiple regression analyses in artificial-grammar learning : the importance of control groups
(2009)
In artificial-grammar learning, it is crucial to ensure that above-chance performance in the test stage is due to learning in the training stage but not due to judgemental biases. Here we argue that multiple regression analysis call be successfully combined with the use of control groups to assess whether participants were able to transfer knowledge acquired during training where making judgements about test stimuli. We compared the regression weights of judgements in a transfer condition (training and test strings were constructed by the same grammar but with different letters) with those in a control condition. Predictors were identical in both conditions-judgements of control participants were treated as if they were based oil knowledge gained in a standard training stage. The results of this experiment as well as reanalyses of a former study support the usefulness of our approach.
Motivation
(2009)
In this article, we revisit the mindless reading paradigm from the perspective of computational modeling. In the standard version of the paradigm, participants read sentences in both their normal version as well as the transformed (or mindless) version where each letter is replaced with a z. z-String scanning shares the oculomotor requirements with reading but none of the higher-level lexical and semantic processes. Here we use the z-string scanning task to validate the SWIFT model of saccade generation [Engbert, R., Nuthmann, A., Richter, E., & Kliegl, R. (2005). SWIFT: A dynamical model of saccade generation during reading. Psychological Review, 112(4), 777-813] as an example for an advanced theory of eye-movement control in reading. We test the central assumption of spatially distributed processing across an attentional gradient proposed by the SWIFT model. Key experimental results like prolonged average fixation durations in z-string scanning compared to normal reading and the existence of a string-length effect on fixation durations and probabilities were reproduced by the model, which lends support to the model's assumptions on visual processing. Moreover, simulation results for patterns of regressive saccades in z-string scanning confirm SWIFT's concept of activation field dynamics for the selection of saccade targets.
It has recently been demonstrated that the presentation of visual oddballs induces a prolonged inhibition of microsaccades. The amplitude of the P300 component in event-related potentials (ERPs) has been shown to be sensitive to the category (target vs. nontarget) of the eliciting stimulus, its overall probability, and the preceding stimulus sequence. In the present study we further specify the functional underpinnings of the prolonged microsaccadic inhibition in the visual oddball task, showing that the stimulus category, the frequency of a stimulus, and the preceding stimulus sequence influence microsaccade rate. Furthermore, by co-recording ERPs and eye movements, we were able to demonstrate that, despite being largely sensitive to the same experimental manipulation, the amplitude of P300 and the microsaccadic inhibition predict each other only weakly.
Contrary to common wisdom, fixations are a dynamically rich behavior, composed of continual, miniature eye movements, of which microsaccades are the most salient component. Over the last few years, interest in these small movements has risen dramatically, driven by both neurophysiological and psychophysical results and by advances in techniques, analysis, and modeling of eye movements. The field has a long history but a significant portion of the earlier work has gone missing in the current literature, in part, as a result of the collapse of the field in the 1980s that followed a series of discouraging results. The present review compiles 60 years of work demonstrating the unique contribution of microsaccades to visual and oculomotor function. Specifically, the review covers the contribution of microsaccades to (1) the control of fixation position, (2) the reduction of perceptual fading and the continuity of perception, (3) the generation of synchronized visual transients, (4) visual acuity, (5) scanning of small spatial regions, (6) shifts of spatial attention, (7) resolving perceptual ambiguities in the face of multistable perception, as well as several other functions. The accumulated evidence demonstrates that microsaccades serve both perceptual and oculomotor goals and although in some cases their contribution is neither necessary nor unique, microsaccades are a malleable tool conveniently employed by the visual system.
OBJECTIVE: To examine factors associated with the maternal perception of the weight status in related and unrelated children and to examine whether associated health risks for children's physical and mental health are recognized. PATIENTS AND METHODS: Two hundred nineteen mothers with children between 3 and 6 years of age took part in this study. The participating mothers were recruited from inpatient clinics and kindergartens. Parents were presented with 9 silhouettes representing different age- and gender-specific BMI percentiles. Demographic and weight-related variables were assessed with regard to their influence on the accuracy of the maternal weight estimation in general and for their own child. RESULTS: Of the participating mothers, 64.5% identified the overweight silhouettes of preschool- aged children correctly. However, only 48.8% of the mothers identified the overweight silhouettes associated with an increased risk for physical health problems, and 38.7% identified the silhouettes associated with an increased mental health risk. Mothers with a lower educational background were more likely to misclassify the overweight silhouettes and underestimate the associated health problems. For their own child, only 40.3% of the mothers chose silhouettes that were in agreement with the objective weight status of their child. This underestimation was associated with a higher maternal and child weight status but not with a general inability to identify the weight status of children. CONCLUSIONS: Identifying unrelated overweight silhouettes is influenced by maternal education level, whereas estimating their own child's weight status is influenced by the weight status of the mother and the child. Hence, feedback on the child's risk to become overweight is necessary to increase maternal risk awareness and willingness to take part in prevention programs.
Background: Research concerning child's food intake have considered various influencing factors, for example parental feeding strategies, demographic and weight factors. At this time, however, there are few findings that explore these factors simultaneously. Accordingly, the aim of this study was to test a structural equation model regarding the associations between maternal feeding strategies and child's food intake. Methods: 556 mothers and their children between 1 and 10 years of age participated in this cross-sectional study. Besides socio-demographic and weight data, the mothers were asked about their feeding strategies as well as their child's food intake. Results: The well-fitting model explained 73% of the variance in the child's consumption of healthy and 34% of unhealthy food. In addition to the effect of the mother's social status and the child's age, a rewarding and modeling feeding behavior significantly influenced the child's food intake. Conclusion: The results highlight the relevance of maternal feeding behavior on the child's food intake. In terms of preventing eating- or weight-related problems, the findings indicate the usefulness of training parents in explicit modeling behavior and avoiding food as a reward.
Vorgestellt wird ein Instrument zur Erhebung muetterlicher Steuerungsstrategien in der Essenssituation (ISS), fuer deren Erfassung bislang kein deutschsprachiges, ueberprueftes Instrument vorliegt. Dazu wurde an 163 Muettern mit Vorschulkindern ein auf Grundlage bereits existierender englischsprachiger Instrumente (CFQ, CFSQ) sowie Fokusinterviews mit Experten und Muettern entstandener Itempool ueberprueft. Die Studie berichtet ueber die faktoren- und itemanalytischen Ergebnisse, nach denen sich 21 Items als trennscharf und verstaendlich erwiesen. Eine explorative Faktorenanalyse ergab sechs Faktoren, die zusammen 68% der Varianz aufklaerten. Sie umfassen aktive Strategien, wie Restriktion, Draengen und Belohnung, aber auch passive Steuerung durch Vorbild, Monitoring und die Staerkung der Eigenverantwortung des Kindes. Analysen zu Unterschieden im Steuerungsverhalten der Mutter bestaetigten die Faehigkeit des Instrumentes zur Differenzierung zwischen Muettern mit verschiedenem soziooekonomischen Status und Kindern unterschiedlichen Gewichts.
Compared with visual and auditory imagery, little is known about olfactory imagery. There is evidence that respiration may be altered by both olfactory perception and olfactory imagery. In order to investigate this relationship, breathing parameters (respiratory minute volume, respiratory amplitude, and breathing rate) in human subjects during olfactory perception and olfactory imagery were investigated. Fifty-six subjects having normal olfactory function were tested. Nasal respiration was measured using a respiratory pressure sensor. Using an experimental block design, we alternately presented odors or asked the subjects to imagine a given smell. Four different pleasant odors were used: banana, rose, coffee, and lemon odor. We detected a significant increase in respiratory minute volume between olfactory perception and the baseline condition as well as between olfactory imagery and baseline condition. Additionally we found significant differences in the respiratory amplitude between imagery and baseline condition and between odor and imagery condition. Differences in the breathing rate between olfactory perception, olfactory imagery, and baseline were not statistically significant. We conclude from our results that olfactory perception and olfactory imagery both have effects on the human respiratory profile and that these effects are based on a common underlying mechanism.
Previous research examining gene-environment interaction (G x E) with regard to vulnerability to depression and anxiety has yielded conflicting results. The present study was designed to further investigate G x F between 5-HTTLPR and exposure to environmental adversity, using different phenotypic and genotypic characterizations as well as different types of adversity within a prospective study design. Data were available from an ongoing epidemiological cohort Study following the outcome of early risk factors from birth to adulthood. At age 19 yr, 309 participants (142 males, 167 females) were characterized on measures of depression and anxiety through interview and questionnaire (DSM-IV diagnosis, Beck Depression Inventory, Harm Avoidance). Environmental adversity was assessed at birth (family adversity), and at age 19 yr (stressful life events). Bi- and tri-allelic 5-HTTLPR genotypes were obtained from genomic DNA. Results indicated that depression and anxiety in 19-yr-olds were strongly associated with both family adversity and stressful life events. Individuals with the LL genotype of 5-HTTLPR who were exposed to high family adversity displayed significantly higher rates of depressive or anxiety disorders and had more depressive symptoms than those without either condition. This G x E replicates recent findings from an epidemiological cohort study of adolescents but is in contrast to many previous reports suggesting an interaction with the S allele. No evidence for G x E was obtained with regard to current stressful life events and trait anxiety. One possible source for the conflicting findings might be attributed to heterogeneity in depression phenotypes and environmental adversity.
The aim of this study was to investigate the effects of three different forms of strategy instruction on 210 elementary-school students' reading comprehension. Students were assigned to any one of three intervention conditions or to a traditional instruction condition (control condition). Training students were taught four reading strategies (summarizing, questioning, clarifying, predicting) and practiced these strategies in small groups (reciprocal teaching), pairs, or instructor-guided small groups. At both the post- and follow-up test the intervention students attained higher scores on an experiment-developed task of reading comprehension and strategy use than the control students who received traditional instruction. Furthermore, students who practiced reciprocal teaching in small groups outperformed use than the control students who received traditional instruction groups on a standardized reading comprehension test.
Background: Evidence from animal studies supports a role for serotonin transporter gene promoter polymorphism (5-HTTLPR) gene-environment interaction (G X E) in the development of excessive alcohol intake. Few studies in humans have been conducted on this topic, yielding inconsistent results. The present study aims to further explore G x E between 5-HTTLPR and exposure to psychosocial adversity on alcohol consumption in a high-risk community sample of young adults. Methods: Data were collected as part of the Mannheim Study of Children at Risk, an ongoing epidemiological cohort study following the outcome of early risk factors from birth into young adulthood. At age 19 years, 309 participants (142 male participants, 167 female participants) were genotyped for the biallelic and triallelic 5-HTTLPR and were administered a 45-day alcohol timeline follow-back interview, providing measures of the total number of drinks and the number of binge drinking days. Psychosocial adversity was assessed at birth (family adversity) and at age 19 (negative life events). Results: In contrast to various previous reports, a significant G x E emerged, indicating that, when exposed to high psychosocial adversity, individuals with the LL genotype of 5-HTTLPR exhibited more hazardous drinking than those carrying the S allele or those without exposure to adversity. This effect, which was confined to male participants, held both for different classifications of 5-HTTLPR and different types of adversity. Conclusions: One explanation for the discrepant results might be heterogeneity in alcohol phenotypes. While the L allele relates more strongly to early-onset alcoholism, the S allele may be linked more closely to alcohol use associated with anxiety and depression.
There is ample evidence that the early initiation of alcohol use is a risk factor for the development of later alcohol-related problems. The purpose of the current study was to examine whether this association can be explained by indicators of a common underlying susceptibility or whether age at drinking onset may be considered as an independent predictor of later drinking behavior, suggesting a potential causal relationship. Participants were drawn from a prospective cohort study of the long-term outcomes of early risk factors followed up from birth onwards. Structured interviews were administered to 304 participants to assess age at first drink and current drinking behavior. Data on risk factors, including early family adversity, parental alcohol use, childhood psychopathology and stressful life events, were repeatedly collected during childhood using standardized parent interviews. In addition, information on genotype was considered. Results confirmed previous work demonstrating that hazardous alcohol consumption is related to early-adolescent drinking onset. A younger age of first drink was significantly predicted by 5-HTTLPR genotype and the degree of preceding externalizing symptoms, and both factors were related to increased consumption or harmful alcohol use at age 19. However, even after controlling for these potential explanatory factors, earlier age at drinking onset remained a strong predictor of heavy alcohol consumption in young adulthood. The present longitudinal study adds to the current literature indicating that the early onset - adult hazardous drinking association cannot solely be attributed to shared genetic and psychopathologic risk factors as examined in this study.
The method of twin surrogates has been introduced to test for phase synchronization of complex systems in the case of passive experiments. In this paper we derive new analytical expressions for the number of twins depending on the size of the neighborhood, as well as on the length of the trajectory. This allows us to determine the optimal parameters for the generation of twin surrogates. Furthermore, we determine the quality of the twin surrogates with respect to several linear and nonlinear statistics depending on the parameters of the method. In the second part of the paper we perform a hypothesis test for phase synchronization in the case of experimental data from fixational eye movements. These miniature eye movements have been shown to play a central role in neural information processing underlying the perception of static visual scenes. The high number of data sets (21 subjects and 30 trials per person) allows us to compare the generated twin surrogates with the "natural" surrogates that correspond to the different trials. We show that the generated twin surrogates reproduce very well all linear and nonlinear characteristics of the underlying experimental system. The synchronization analysis of fixational eye movements by means of twin surrogates reveals that the synchronization between the left and right eye is significant, indicating that either the centers in the brain stem generating fixational eye movements are closely linked, or, alternatively that there is only one center controlling both eyes.
This prospective longitudinal study of a representative community sample of children and adolescents (N = 269) examined the long-term course and predictive power of psychiatric symptoms in childhood/adolescence for diagnostic outcome (ICD-10) 18 years later at adult age. At both cross-sectional assessments, baseline (1980-1984) and the 18-year follow-up (2001-2004), psychiatric symptoms were assessed using the 'Standardized Psychiatric Interview' (Goldberg et al. in Br J Prev Soc Med 24:18-23, 1970). At follow-up, study participants were reassessed with the standardized M-CIDI (Wittchen and Pfister in Manual und Durchfuhrungsbeschreibung des DIA-X-M-CIDI, Swets and Zeitlinger, Frankfurt, 1997) interview. The participation rate at 18-year follow-up was 82% of those alive. The frequency of clinically relevant depressive symptoms and symptoms of anxiety or phobia was considerably higher when the participants were younger (baseline assessment at childhood, adolescent age) as compared to their scores in adult age. Increased levels of somatic symptoms, fatigue, irritability, sleep disturbances, depression, anxiety and worry as well as phobic symptoms in childhood/adolescence were related to a higher risk of suffering from a psychiatric disorder in adulthood. Depressive symptoms predicted both mood disorders and substance use disorders in adulthood. Phobias predicted later anxiety disorders. These data spanning almost two decades add significant information to the existing literature on the course of mental disorders in the community during the transition from adolescence to adulthood.
Exposure to violent video games and aggression in German adolescents : a longitudinal analysis
(2009)
The relationship between exposure to violent electronic games and aggressive cognitions and behavior was examined in a longitudinal study. A total of 295 German adolescents completed the measures of violent video game usage, endorsement of aggressive norms, hostile attribution bias, and physical as well as indirect/relational aggression cross- sectionally, and a subsample of N = 143 was measured again 30 months later. Cross-sectional results at T1 showed a direct relationship between violent game usage and aggressive norms, and an indirect link to hostile attribution bias through aggressive norms. In combination, exposure to game violence, normative beliefs, and hostile attribution bias predicted physical and indirect/relational aggression. Longitudinal analyses using path analysis showed that violence exposure at T1 predicted physical (but not indirect/relational) aggression 30 months later, whereas aggression at T1 was unrelated to later video game use. Exposure to violent games at T1 influenced physical (but not indirect/relational) aggression at T2 via an increase of aggressive norms and hostile attribution bias. The findings are discussed in relation to social-cognitive explanations of long-term effects of media violence on aggression.
The present study aimed to clarify the functional role of genes in the dopamine and serotonin systems by examining whether polymorphisms in these genes are related to adolescent externalizing behavior either alone or in interaction with each other. Participants were selected from an ongoing prospective study of the outcome of early risk factors. At age 15 years, 298 adolescents (144 males, 154 females) completed the Youth Self Report, 296 primary caregivers the Child Behavior Checklist and 253 teachers the Teacher Report Form. DNA was genotyped for the DRD4 exon III VNTR and the 5-HTTLPR polymorphisms. Results revealed that individuals with the DRD4 7r allele reported significantly more externalizing behavior than carriers of other variants. In addition, a significant interaction emerged, indicating that adolescents carrying two copies of the 5-HTTLPR short allele and the DRD4 7r variant scored highest on aggressive and/or delinquent behavior compared to other genotypes. This result suggests an effect of 5-HTTLPR on externalizing behavior in the presence of DRD4 7r but no effect in its absence.
BACKGROUND: Feedback from the body is assumed to be altered in depression. Nevertheless, empirical studies investigating this assumed relationship remain sparse. This study aimed to examine interrelations between the ability to perceive heartbeats accurately (interoceptive awareness), depressive symptoms, and anxiety in healthy participants. METHODS: A well-validated heartbeat perception task to measure interoceptive awareness together with two questionnaires indexing anxiety and depression were administered to 119 participants. RESULTS: As main results we observed a negative correlation between heartbeat perception and depression. Only when focussing on high anxiety levels this negative correlation coefficient between depression and interoception remained significant. CONCLUSIONS: Our results highlight the possible relationship between depressive symptoms and interoceptive awareness and may have further implications for theoretical models of anxiety disorders and their treatment. Further research is required to examine the potential consequences of altering interoceptive awareness in healthy subjects in relation to depression and anxiety.
Es werden Befunde aus einer prospektiven Laengsschnittstudie praesentiert, in der 321 Probanden im Alter von 8, 13, 18 und 25 Jahren untersucht werden konnten; ihre Dunkelfelddelinquenz wurde mit 18 und 25 Jahren erfasst. Wir suchten nach Assoziationen zur Delinquenzentwicklung und erwarteten Unterschiede zwischen auf das Jugendalter beschraenkter gegenueber ins fruehe Erwachsenenalter fortgesetzter sowie spaet, d.h. nach dem Alter von 18 Jahren, beginnender Delinquenz. Wir fanden gemeinsame Risikofaktoren und fuer die drei Verlaufstypen spezifische Risikokonstellationen, die eher im Jugendalter als in der Kindheit identifiziert wurden. Widrige familiaere Bedingungen, Entwicklungsverzoegerungen und psychische Stoerungen scheinen mit Delinquenz als eher persistentem Verhalten assoziiert.
Depressive Störungen
(2009)