Brain activation during spatial updating and attentive tracking of moving targets

Keeping aware of the locations of objects while one is moving requires the updating of spatial representations. As long as the objects are visible, attentional tracking is sufficient, but knowing where objects out of view went in relation to one's own body involves an updating of spatial working memory. Here, multiple object tracking was employed to study spatial updating and its neural correlates. In a dynamic 3D-scene, targets moved among visually indistinguishable distractors. The targets and distractors either stayed visible during continuous viewpoint changes or they turned invisible. The parametric variation of tracking load revealed load-dependent activations of the intraparietal sulcus, the superior parietal lobule, and the lateral occipital cortex in response to the attentive tracking task. Viewpoint changes with invisible objects that demanded retention and updating produced load-dependent activation only in the precuneus in line with its presumed involvement in updating spatial working memory.     

Mixing metaphors in the cerebral hemispheres: what happens when careers collide?

Are processes of figurative comparison and figurative categorization different? An experiment combining alternative-sense and matched-sense metaphor priming with a divided visual field assessment technique sought to isolate processes of comparison and categorization in the 2 cerebral hemispheres. For target metaphors presented in the right visual field/left cerebral hemisphere (RVF/LH), only matched-sense primes were facilitative. Literal primes and alternative-sense primes had no effect on comprehension time compared to the unprimed baseline. The effects of matched-sense primes were additive with the rated conventionality of the targets. For target metaphors presented to the left visual field/right cerebral hemisphere (LVF/RH), matched-sense primes were again additively facilitative. However, alternative-sense primes, though facilitative overall, seemed to eliminate the preexisting advantages of conventional target metaphor senses in the LVF/RH in favor of metaphoric senses similar to those of the primes. These findings are consistent with tightly controlled categorical coding in the LH and coarse, flexible, context-dependent coding in the RH.     

Perceived Stress and Comorbid Illness Predict Depressive Symptomatology in People with Coeliac Disease

A high prevalence of depression is found in people with coeliac disease (CD). People with CD who are depressed are less likely to manage their illness effectively, which may lead to complications. Identification of variables associated with depression in people with CD may facilitate early detection and intervention. Participants were 749 members (125 males, 622 females) of the Queensland Coeliac Society (aged 18–88 years), recruited via a mailout. Participants completed the Modified Zung Self‐Rating Depression Scale, the Perceived Stress Scale, and the Perceived Consequences Subscale (from the Revised Illness Perception Questionnaire). Stress (p = .001) and comorbid medical illness (p = .01) were significantly associated with depression in CD. The current study made an original contribution to the body of literature by identifying stress and comorbid medical illness as predictors of depression in CD.     

Verbal interference suppresses exact numerical representation

Language for number is an important case study of the relationship between language and cognition because the mechanisms of non-verbal numerical cognition are well-understood. When the Pirahã (an Amazonian hunter-gatherer tribe who have no exact number words) are tested in non-verbal numerical tasks, they are able to perform one-to-one matching tasks but make errors in more difficult tasks. Their pattern of errors suggests that they are using analog magnitude estimation, an evolutionarily- and developmentally-conserved mechanism for estimating quantities. Here we show that English-speaking participants rely on the same mechanisms when verbal number representations are unavailable due to verbal interference. Followup experiments demonstrate that the effects of verbal interference are primarily manifest during encoding of quantity information, and—using a new procedure for matching difficulty of interference tasks for individual participants—that the effects are restricted to verbal interference. These results are consistent with the hypothesis that number words are used online to encode, store, and manipulate numerical information. This linguistic strategy complements, rather than altering or replacing, non-verbal representations.     

Generalization gradients in human predictive learning: Effects of discrimination training and within-subjects testing

Generalization gradients have been investigated widely in animal conditioning experiments, but much less so in human predictive learning tasks. Here, we apply the experimental design of a recent study on conditioned fear generalization in humans (Lissek et al., 2008) to a predictive learning task, and examine the effects of a number of relevant procedural parameters drawn from the generalization literature in animal conditioning. Experiment 1 shows that prior discrimination learning and steady-state testing procedures sharpen the gradient; Experiment 2 shows that within-subjects testing of the range of generalization stimuli also sharpens the gradient. In addition, Experiment 2 shows that, in case of very flat initial generalization, an orderly gradient can reveal itself through differential rates of extinction learning. Finally, Experiment 2 also evidenced an orderly gradient of generalization-of-extinction. These results suggest that discrimination processes have an important effect on the generalization of predictive learning in humans, and highlight behavioral analogies between animal conditioning and human predictive learning.     

The bystander-effect: a meta-analytic review on bystander intervention in dangerous and non-dangerous emergencies

Research on bystander intervention has produced a great number of studies showing that the presence of other people in a critical situation reduces the likelihood that an individual will help. As the last systematic review of bystander research was published in 1981 and was not a quantitative meta-analysis in the modern sense, the present meta-analysis updates the knowledge about the bystander effect and its potential moderators. The present work (a) integrates the bystander literature from the 1960s to 2010, (b) provides statistical tests of potential moderators, and (c) presents new theoretical and empirical perspectives on the novel finding of non-negative bystander effects in certain dangerous emergencies as well as situations where bystanders are a source of physical support for the potentially intervening individual. In a fixed effects model, data from over 7,700 participants and 105 independent effect sizes revealed an overall effect size of g = -0.35. The bystander effect was attenuated when situations were perceived as dangerous (compared with non-dangerous), perpetrators were present (compared with non-present), and the costs of intervention were physical (compared with non-physical). This pattern of findings is consistent with the arousal-cost-reward model, which proposes that dangerous emergencies are recognized faster and more clearly as real emergencies, thereby inducing higher levels of arousal and hence more helping. We also identified situations where bystanders provide welcome physical support for the potentially intervening individual and thus reduce the bystander effect, such as when the bystanders were exclusively male, when they were naive rather than passive confederates or only virtually present persons, and when the bystanders were not strangers.     

Development of the Mental Clutter Scale

Mental fog is a core symptom of fibromyalgia. Its definition and measurement are central to an understanding of fibromyalgia-related cognitive disability. The Mental Clutter Scale was designed to measure mental fogginess. In an exploratory factor analysis of two different samples (n=128 and n=170), cognitive symptoms of fibromyalgia loaded on 2 dimensions: cognition and mental clarity. The mental clarity factor comprised 8 items with factor loadings greater than .60 and was named the Mental Clutter Scale. The factor stability of the new scale was good, internal consistency was .95, and test-retest reliability over a median of 5 days was .92. The 8-item scale is a quick measure of mental fog that provides clinicians with information about cognitive functioning in fibromyalgia.     

Speed of reasoning and its relation to reasoning ability

The study investigates empirical properties of reasoning speed which is conceived as the fluency of solving reasoning problems. Responses and response times in reasoning tasks are modeled jointly to clarify the covariance structure of reasoning speed and reasoning ability. To determine underlying abilities, the predictive validities of two cognitive covariates, namely perceptual and executive attention, are investigated. A sample of N = 230 test takers completed a reasoning test, Advanced Progressive Matrices (APM), and attention tests indicating perceptual and executive attention. For modeling responses the two-parameter normal ogive model, and for modeling response times the two-parameter lognormal model was applied. Results suggest that reasoning speed is a unidimensional construct representing significant individual differences, and that reasoning speed and ability are negatively correlated but clearly distinguishable constructs. Perceptual and executive attention showed differential effects on reasoning speed and reasoning ability, i.e., reasoning speed is explained by executive attention only, while reasoning ability is explained by both covariates. Implications for the assessment of reasoning are discussed.