Low target prevalence is a stubborn source of errors in visual search tasks

In visual search tasks, observers look for targets in displays containing distractors. Likelihood that targets will be missed varies with target prevalence, the frequency with which targets are presented across trials. Miss error rates are much higher at low target prevalence (1%-2%) than at high prevalence (50%). Unfortunately, low prevalence is characteristic of important search tasks such as airport security and medical screening where miss errors are dangerous. A series of experiments show this prevalence effect is very robust. In signal detection terms, the prevalence effect can be explained as a criterion shift and not a change in sensitivity. Several efforts to induce observers to adopt a better criterion fail. However, a regime of brief retraining periods with high prevalence and full feedback allows observers to hold a good criterion during periods of low prevalence with no feedback.     

The role of spatial and nonspatial information in visual selection

Even though it is undisputed that prior information regarding the location of a target affects visual selection, the issue of whether information regarding nonspatial features, such as color and shape, has similar effects has been a matter of debate since the early 1980s. In the study described in this article, measures derived from signal detection theory were used to show that perceptual sensitivity is affected by a top-down set for spatial information but not by a top-down set for nonspatial information. This indicates that knowing where the target singleton is affects perceptual selectivity but that knowing what it is does not help selectivity. Furthermore, perceptual sensitivity can be enhanced by nonspatial features, but only through a process related to bottom-up priming. These findings have important implications for models of visual selection.     

In sight, out of mind: the role of eye movements in the rapid resumption of visual search

Three experiments investigated the role of eye movements in the rapid resumption of an interrupted search. Passive monitoring of eye position in Experiment 1 showed that rapid resumption was associated with a short distance between the eye and the target on the next-to-last look before target detection. Experiments 2 and 3 used two different methods for presenting the target to the point of eye fixation on some trials. If eye position alone is predictive, rapid resumption should increase when the target is near fixation. The results showed that gaze-contingent targets increased overall search success, but that the proportion of rapid responses decreased dramatically. We conclude that rather than depending on a high-quality single look at a search target, rapid resumption of search depends on two glances; a first glance in which a hypothesis is formed, and a second glance in which the hypothesis is confirmed.     

Extending the spectrum idea: child personality,parenting and psychopathology

The spectrum hypothesis, postulating that differences between referred and non‐referred samples are confined to mean level differences, is elaborated by exploring whether the covariation between child problem behaviour and its predictors—child personality and parenting, rated by mothers—is similar in referred (N = 205) and non‐referred (N = 596) children and whether personality by parenting interactions can be generalized across samples. Results showed significant mean level differences for all the variables. Both personality and parenting explained problem behaviour, with some differences in strength of the effects across samples. Parenting by personality interactions mainly predicted externalizing behaviour, with benevolence and conscientiousness as the most prominent moderators. Results confirmed that moderators of problem behaviour operate similarly in the two samples, thus corroborating the spectrum hypothesis. Copyright © 2006 John Wiley & Sons, Ltd.     

Neural substrates of word generation during stroke recovery: the influence of cortical hypoperfusion

Several studies have demonstrated reorganization of cognitive and motor function caused by stroke. This study examined the influence of hypoperfused brain regions, in addition to the area of the infarct itself, on reorganization of the cognitive processes underlying word generation in stroke patients. In addition, we also sought to determine the influence of hypoperfusion on the blood oxygen level dependent/(BOLD) effect. Subjects with left and right subacute or chronic subcortical strokes, along with normal controls, were imaged while performing a verbal fluency task (word generation). The study population included six normal subject and six stroke patients with subcortical infarcts and cortical hypoperfusion in the middle cerebral artery territory who had recovered or improved markedly in word fluency. While normal subjects displayed a left-lateralized fronto-temporo-parietal and bilateral cingulo-striatal-thalamic-cerebellar network, the activation pattern of stroke patients was determined both by the hypoperfused regions and infarcted areas of the brain. Specifically, patients showed diminished BOLD effect in the cortical regions that were hypoperfused, even though their infarcts were subcortical, and showed increased BOLD effect in the homologous regions of the normal hemisphere. This finding raises the possibility that cortical hypoperfusion in the absence of infarct can cause shift of language functions to the opposite, intact hemisphere. However, reduced BOLD effect in the task relative to rest was found in hypoperfused regions in two patients, raising the possibility that regional function persisted, even though vascular reactivity was impaired. Results illustrate the complexities of functional imaging studies of recovery in patients with vascular lesions.     

When gains loom larger than losses: reversed loss aversion for small amounts of money

Previous research has generally shown that people are loss averse; that is, they weigh losses more heavily than gains. In a series of three experiments, we found that for small outcomes, this pattern is reversed, and gains loom larger than losses. We explain this reversal on the basis of (a) the hedonic principle, which states that individuals are motivated to maximize pleasure and to minimize pain, and (b) the assumption that small losses are more easily discounted cognitively than large losses are.     

Investigating Web‐Based Recruitment Sources: Employee testimonials vs word‐of‐mouse

Although the internet has dramatically changed recruitment practices, many web‐based recruitment sources have not yet been investigated. The present study examines the effects of web‐based employee testimonials and web‐based word‐of‐mouth (i.e., ‘word‐of‐mouse’) on organizational attraction. The source credibility framework is used to compare these company‐dependent and company‐independent recruitment sources. In a sample of potential applicants for a head nurse position, word‐of‐mouse was associated with higher organizational attractiveness than web‐based employee testimonials. However, potential applicants were more attracted when testimonials provided information about individual employees than about the organization. Conversely, word‐of‐mouse was associated with higher organizational attractiveness and more organizational pursuit behavior when it focused on the organization instead of on employees. Most of these effects were mediated by credibility perceptions.     

Football hooliganism: comparing self‐awareness and social identity theory explanations

The emergence of research interest in group violence in general and football hooliganism in particular has been explained by various models generally relying on situational or individual differences accounts. Yet, these two research traditions have largely evolved independently, showing little or no interaction. In the present study (N = 109), we integrate measures of these two approaches and the results reveal that social identity was more predictive of self‐reported physical aggression than of loss of private and public self‐awareness. Moreover, attitudes towards violence were the most marked predictor variables of both physical and verbal aggression. In the discussion, the moderator effect of social identity and attitudes about violence on physical aggression is elaborated upon. Copyright © 2007 John Wiley & Sons, Ltd.     

Social Support as Predictor of Psychopathology in the Adolescent Offspring of Psychiatric Patients

The potential role of social support for the adolescent offspring of psychiatric patients has hitherto not been examined. We examined whether the adolescent's level of psychiatric symptoms is dependent on the content and the function of social support (whether direct or moderating), controlling for perceived stress. In a cross-sectional design, 40 adolescents (11–18 yrs) with a parent exhibiting an affective or personality disorder were given several questionnaires, including the Youth Self Report (Achenbach), a Social Support Inventory, and the MUSIC, an inventory assessing perceived emotional and physiological stress reactions. The social support inventory consisted of three subscales to assess the positive and negative perception of social support, and the discrepancy between demand and supply of social support. The mentally-ill parents were given the General Health Questionnaire (GHQ). Data were then analyzed using multiple linear regression analyses. Analyses showed that perceived stress and negative social support predicted the adolescent's level of psychiatric symptoms, and that social support served as a direct effect, and was independent of parental GHQ score. Results are discussed and the presently under-utilized potential of social support for this population at risk is highlighted as something warranting increased attention both in terms of research and practical preventative steps.     

Does negative mood influence self-report assessment of individual and relational measures? An experimental analysis

The present study was designed to test the influence of negative mood on the self-report of individual and relational correlates of depression and marital distress. The authors applied a combined experimental mood induction procedure, based on music, autobiographical recall, and environmental manipulation. Results showed that the mood manipulation was effective, and the depressed Mood Induction Procedure (MIP) and neutral MIP groups did not differ in their self-rated measures of the above-mentioned variables. In conclusion, the authors argue that these measures are generally insensitive to depressed mood, providing an important contribution to this literature.