Revisiting the association of aggression and suicidal behavior in schizophrenic inpatients

Our study investigated the association of aggression and suicidal behavior in schizophrenic inpatients. Eight thousand nine hundred one admissions for schizophrenia (1998-2007) to a psychiatric university hospital were included. Schizophrenic suicides (n = 7)/suicide attempters (n = 40) were compared to suicides (n = 30)/suicide attempters (n = 186) with other diagnoses and to schizophrenic non-attempters regarding aggression. Logistic regression analysis was performed to explore risk factors for attempted suicide. Schizophrenic suicides/suicide attempters did not differ from other suicides/suicide attempters or from schizophrenic non-attempters with regard to aggression. Risk of inpatient suicide attempt was increased for patients with attempted suicide at admission, high school graduation, and disorganized subtype. Aggression could not be found to be a predictor of attempted suicide. Aggression seems to have a minor role for suicidal behavior in schizophrenia.     

Evidence of separable spatial representations in a virtual navigation task

Three experiments investigated spatial orientation in a virtual navigation task. Subjects had to adjust a homing vector indicating their end position relative to the origin of the path. It was demonstrated that sparse visual flow was sufficient for accurate path integration. Moreover, subjects were found to prefer a distinct egocentric or allocentric reference frame to solve the task. "Turners" reacted as if they had taken on the new orientation during turns of the path by mentally rotating their sagittal axis (egocentric frame). "Nonturners," by contrast, tracked the new orientation without adopting it (allocentric frame). When instructed to use their nonpreferred reference frame, both groups displayed no decline in response accuracy relative to their preferred frame; even when presented with reaction formats based on either ego or allocentric coordinates, with format unpredictable on a trial, both groups responded highly accurately. These findings support the assumption of coexisting spatial representations during navigation.     

A new learning paradigm elicits fast visual discrimination in pigeons

The authors describe a novel multistimulus, multiple-matching learning paradigm for pigeons, which they believe not only simulates pigeons' natural foraging behavior but also more realistically shows their visual discrimination ability. A touch screen thin film transistor panel shows a stimulus configuration consisting of a 2-dimensional array of bitmap images that changes from trial to trial. The pigeon's task during each trial is to peck at images that are defined as positive by the experimenter. An experiment exploring the ability of pigeons to discriminate between achromatic male and female human faces demonstrated the effectiveness of the procedure. In contrast to 12 pigeons that show little improvement over 60 hr of go/no-go discrimination training, 14 multiple-matching pigeons mastered the problem within a few hours.     

Evaluating interobserver reliability of interval data

Previous recommendations to employ occurrence, nonoccurrence, and overall estimates of interobserver reliability for interval data are reviewed. A rationale for comparing obtained reliability to reliability that would result from a random-chance model is explained. Formulae and graphic functions are presented to allow for the determination of chance agreement for each of the three indices, given any obtained per cent of intervals in which a response is recorded to occur. All indices are interpretable throughout the range of possible obtained values for the per cent of intervals in which a response is recorded. The level of chance agreement simply changes with changing values. Statistical procedures that could be used to determine whether obtained reliability is significantly superior to chance reliability are reviewed. These procedures are rejected because they yield significance levels that are partly a function of sample sizes and because there are no general rules to govern acceptable significance levels depending on the sizes of samples employed.     

Local and global orientation in visual search

Six experiments investigated the role of global (shape) and local (contour) orientation in visual search for an orientation target. Experiment 1 demonstrated thatsearch for a conjunction of local contours with a distinct global orientation was less efficient than search for a target featurally distinct in terms of both global and local contour orientation. However, Experiments 2 and 4 demonstrated that the presence of a unique line contour was neither sufficient nor necessary to allow efficient search. Experiment 5 found thatsearch for a local orientation difference was strongly impeded by irrelevant variation in global orientation, arguing for a preeminent role for global orientation. Finally, Experiment 6 demonstrated that the orientation search asymmetry holds for the global orientation of stimuli. Taken together, the results are consistent with visual search processes guided predominately by a representation of global orientation.     

Visual search for dimensionally redundant pop-out targets: parallel-coactive processing of dimensions is location specific

Three visual search experiments investigated redundancy gains for single and dual odd-one-out feature targets that differed from distractors in orientation, color, or both. In Experiment 1, redundant-target displays contained (a) a single target defined in 2 dimensions, (b) dual targets each defined in a different dimension, or (c) dual targets both defined in the same dimension. The redundancy gains, relative to single nonredundant targets, decreased from the first condition on, with violations of J. Miller's (1982) race model inequality (RMI) manifested only in the first 2 conditions. Experiment 2 systematically varied the spatial separation between dual targets each defined in a different dimension. Violations of the RMI were evident only when the 2 targets occupied nearby locations. Experiment 3 provided evidence of RMI violations by dimensionally redundant targets at both precued (likely) and noncued (unlikely) display locations. Taken together, these results suggest that there is coactivation of a common mechanism by target signals in different dimensions (not by signals in the same dimension), that the coactivation effects are spatially specific, and that the coactivated mechanisms are located at a preattentive, perceptual stage of processing.     

Top-down inhibition of search distractors in parallel visual search

In three experiments, we examined distractor inhibition in parallel ("pop-out") visual search. Distractor inhibition was measured in terms of reaction time (RT) to a simple luminance increment probe presented, after the search task response, at display locations that either contained a search distractor (on-probe) or were blank (off-probe). When the search stimuli remained in view, the on-probe (relative to off-probe) RT cost was larger than in a baseline condition in which observers had only to passively view, rather than search, the display. This differential on-probe RT cost, which discounts effects of masking, was interpreted as a measure of distractor inhibition associated with target selection in parallel visual search. Taken together, the results argue that the distractor inhibition is an object-based and local phenomenon that affects all distractors (of a particular type) in an equal manner.     

Book review

Ohne Zusammenfassung

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Book review

     

Krankheitsbewältigung und Überlebenszeit bei Krebskranken

Although a considerable number of studies have addressed the question whether cancer patients’ coping with the disease is a predictor of survival, this issue is still controversely discussed. In the present paper, the previous research on the relationship between coping and survival is reviewed. Whereas some evidence has been produced that active coping is linked with longer survival, results regarding the significance of denial proved inconclusive. However, some researchers demonstrated that emotional distress was predictive of shorter survival, while still others found that the expression of distress predicted a better outcome. Thus, the available data are inconclusive. Moreover, most studies suffered from methodological limitations such as retrospective design, multiple testings, small sample size, heterogeneous sample constitution, unproven assessment instruments, inadequate control for biological prognostic factors, and inadequate statistical analysis. The results of a hypotheses-guided, prospective study with 103 lung cancer patients are presented. Patients were assessed before primary treatment began (inception cohort), using both self-reports and interviewer ratings. After a follow-up of 7 to 8 years, the interviewer rating of active coping predicted a longer survival, and both self and interviewer ratings of depressive coping were predictive of a shorter survival, when entered as continuous variables into a Cox regression model adjusting for biomedical risk factors such as tumor stage, histological classification and Karnofsky performance status. Among the possible mechanisms explaining this relationship are the reactions of the patients to the physical burden of cancer that might be better reflected in subjective measures such as the well-being and quality of life ratings compared with the cruder biomedical classifications, as well as psychoneuroimmunological pathways which, however, to a substantial part remain hypothetical by now, and the compliance with treatment. Further research must engage in experimental studies to clarify the causal relation between coping and survival among patients with cancer.     

Intentionality in non-equilibrium systems? The functional aspects of self-organized pattern formation

Psychology is frequently confronted with mind-body issues—is there a way by which mentalist and physical approaches to cognition can be integrated? Can the intentional attributes of mind be understood in scientific terms? The authors propose that synergetics, the theory of non-linear complex systems, offers steps towards a possible solution to this conundrum. In particular, we maintain that an essential property of self-organized pattern formation lies within its functionality, this being the ability to optimize, respond and adapt ‘meaningfully’ to environmental constraints. Patterns become functional because they consume in a most efficient manner the gradients which cause their evolution, thereby making synergetic pattern formation appear ‘intentional’. We therefore posit that self-organization phenomena may afford basic explanations for the adaptive, intentional and purposive behavior of many complex systems, in particular of cognitive systems. This present approach elaborates on the second law of thermodynamics.