Are UN Peacekeepers at Risk for Suicide?

Media reports connecting UN peacekeeping duties by Canadian soldiers to their subsequent suicide prompted this study of peacekeeping as suicide risk. In a case-control design we retrospectively compared 66 suicides in the Canadian military between 1990 and 1995 with two control groups: (a) 2,601 controls randomly selected from the electronic military database and (b) 66 matched controls with complete personnel and medical data. We found no increased risk of suicide in peacekeepers except among a subgroup of air force personnel. Here confounding individual factors, isolation from supports, and possibly inadequate preparation for deployment elucidated their suicides. Theater of deployment (e.g., Bosnia) did not affect the suicide rate. Military suicides experienced psychosocial stresses and psychiatric illness more often than their matched controls. We conclude that although peacekeeping per se does not increase overall suicide risk, military life-styles may strain interpersonal relationships, encourage alcohol abuse, and contribute to psychiatric illness and suicide in a minority of vulnerable individuals irrespective of peacekeeping assignment. Careful selection, and preparatory military training that encourages intragroup bonding and mutual support, may protect against suicide risk.     

Loneliness in relation to suicide ideation and parasuicide: a population-wide study

Some links between loneliness and different manifestations of suicidal conduct have been reported in variety of subgroups (e.g., college students, the elderly, psychiatric patients). We tested this hypothesis by using the results of a population-wide survey. Strong associations among suicide ideation, parasuicide and different ways of being lonely and alone, defined either subjectively (i.e., the feeling), or objectively (i.e., living alone or being without friends), were observed. Moreover, prevalence of suicide ideation and parasuicide increased with the degree of loneliness. Only minimal differences between men and women were found.     

Mental imagery of visual motion modifies the perception of roll-vection stimulation

When viewing a wide-angle visual display, which rotates in the frontoparallel plane around the line of sight, observers experience an illusory shift of the direction of gravity; this shift leads to an apparent tilt of the body and displaces allocentric space coordinates. In this study, subjects adjusted an indicator to the apparent horizontal while viewing a rotating display. To determine whether top down processes could affect the illusion, the subjects were asked to visualize a rotating configuration of dots onto a blank central portion of the moving visual field. Visualizing dots and actually viewing the dots deflected the spatial judgment in very similar ways. These results demonstrate that top down processing can affect allocentric space coordinates.     

Perceptual continuation and depth in visual phantoms can be explained by perceptual transparency

We try to explain perceptual continuation and depth in the visual-phantom illusion in terms of perceptual transparency. Perceptual continuation of inducing gratings across the occluder in stationary phantoms could be explained with unique transparency, a notion proposed by Anderson (1997 Perception 26 419-453). This view is consistent with a number of previous reports including that of McCourt (1994 Vision Research 34 1609-1617) who criticized the stationary phantom illusion from the viewpoint of his counterphase lightness induction or grating induction, which might involve invalid transparency. Here we confirm that the photopic phantom illusion (Kitaoka et al, 1999 Perception 28 825-834) really gives in-phase lightness induction and involves bistable transparency. It is thus suggested that perceptual continuation and depth in the visual-phantom illusion depend on perceptual transparency.     

Human performance on visually presented Traveling Salesman problems

Little research has been carried out on human performance in optimization problems, such as the Traveling Salesman problem (TSP). Studies by Polivanova (1974, Voprosy Psikhologii, 4, 41–51) and by MacGregor and Ormerod (1996, Perception & Psychophysics, 58, 527–539) suggest that: (1) the complexity of solutions to visually presented TSPs depends on the number of points on the convex hull; and (2) the perception of optimal structure is an innate tendency of the visual system, not subject to individual differences. Results are reported from two experiments. In the first, measures of the total length and completion speed of pathways, and a measure of path uncertainty were compared with optimal solutions produced by an elastic net algorithm and by several heuristic methods. Performance was also compared under instructions to draw the shortest or the most attractive pathway. In the second, various measures of performance were compared with scores on Raven's advanced progressive matrices (APM). The number of points on the convex hull did not determine the relative optimality of solutions, although both this factor and the total number of points influenced solution speed and path uncertainty. Subjects' solutions showed appreciable individual differences, which had a strong correlation with APM scores. The relation between perceptual organization and the process of solving visually presented TSPs is briefly discussed, as is the potential of optimization for providing a conceptual framework for the study of intelligence. Received: 28 December 1998 / Accepted: 20 January 2000     

Sequential analysis of a Simon task--evidence for an attention-shift account

 We investigated the attention-shift hypothesis of the Simon effect by analysing the effect of repeating relevant colour or irrelevant location of the stimulus in four serial reaction time tasks. In Experiment 1 with short response-stimulus intervals (RSI), we assume that there is no time to engage attention at the fixation cross before the onset of a new stimulus. In agreement with the hypothesis, Experiment 1 reveals no Simon effect when the stimulus location is repeated. In Experiment 2 with long RSI, we observe a Simon effect for location repetitions and alternations. In Experiment 3 with long RSI, we hinder the disengagement of attention by displaying the stimulus after response execution. As expected, the Simon effect is reduced for location repetitions. In Experiment 4 with stimuli additionally presented at the fixation cross, responses are faster if the attention shift towards the centrally presented stimulus corresponds with the location of the required response. Additionally, we argue that binding of the stimulus features into an object or event file better explains the so-called blocking of the automatic response-priming route after a noncorresponding trial. Received: 2 February 2000 / Accepted: 10 November 2000     

Familiarisation with faces selectively enhances sensitivity to changes made to the eyes

Two experiments were designed to isolate the facial information utilised in the learning of new faces. In experiments 1 and 2, two groups of subjects were each trained on different groups of faces by means of a dynamic video presentation. They were then shown both trained and novel faces in a same-different decision task, where 'different' trials included manipulations of internal and external facial features, and the task was to decide whether two images were identical or had a difference in one or more features. Both experiments showed that hair change was most easily detected in untrained (unfamiliar) faces. When faces had been trained (familiar), detection of eye changes was selectively enhanced and sensitivity to hair changes was maintained. While previous studies have suggested that familiar face representations are weighted towards their internal features, our experimental results show that this is due to selective enhancement of sensitivity to changes made to the eyes alone, with no reduction in the salience of the hair. Moreover, within the limits of the familiarisation used here, there was no enhancement of the representation of the other internal face features examined.     

Relating ethnic identity, acculturation, and attitudes toward treating minority clients

This study assessed the relationship among the ethnic identity, acculturation, and self-concepts of minority health care professionals and their attitudes toward treating minority clients and using alternative therapies. The sample consisted of 150 medical students of Indian descent. Strong ethnic identity and acculturation related to high self-esteem, self-clarity, the likelihood of treating more minority patients, and the use of alternative therapies. The more "Westernized" participants expressed less of a preference for serving minority patients and believed themselves to be less effective in serving minorities. Gender differences in some aspects of ethnic identity and attitudes were found. The results imply that a focus on acculturation and ethnicity in all client-clinician psychological research is critical, and especially in cases of cultural matching.     

Language and space: some interactions

Is language linked to mental representations of space? There are several reasons to think that language and space might be separated in our cognitive systems, but they nevertheless interact in important ways. These interactions are evident in language viewed as a means of communication and in language considered a form of representation. In communication, spatial factors may be explicit in language itself, such as the spatial-gestural system of American Sign Language. Even the act of conversing with others is a spatial behavior because we orient to the locations of other participants. Language and spatial representations probably converge at an abstract level of concepts and simple spatial schemas.