LEO-II and Satallax on the Sledgehammer test bench

Sledgehammer is a tool that harnesses external first-order automatic theorem provers (ATPs) to discharge interactive proof obligations arising in Isabelle/HOL. We extended it with LEO-II and Satallax, the two most prominent higher-order ATPs, improving its performance on higher-order problems. To explore their usefulness, these ATPs are measured against first-order ATPs and built-in Isabelle tactics on a variety of benchmarks from Isabelle and the TPTP library. Sledgehammer provides an ideal test bench for individual features of LEO-II and Satallax, revealing areas for improvements.     

Protective effect of supportive family relationships and the influence of stressful life events on adolescent adjustment

Abstract

The purpose of this study was to determine the association between the occurrence of stressful life events and internalizing and externalizing problems, and to analyze longitudinally buffering effects of supportive family relationships. To this end, 100 Spanish adolescents were studied twice, when they were in mid-adolescence (15–16 years) and two years later. They completed questionnaires regarding stressful life events, family relationships, and adolescent adjustment. Results showed that high quality parent-adolescent relationships protected boys and girls against the negative consequences of stressful life events on externalizing, but not internalizing, symptoms. The adolescents who enjoyed good relationships with their parents in mid-adolescence did not increase their externalizing problems in late adolescence as consequence of the occurrence of stressful events. However, these stressors did lead to an increase in the number of externalizing problems when the family relationships were of a middle or low quality. These results highlight the important role that supportive family relationships play in the behavioral adjustment of adolescents, protecting them against some negative consequences of stressful life events, and suggest the relevance of supporting parents through resources such as parent education in order to help them to improve their relationships with their adolescents.     

Processing of indexical information requires time: Evidence from change deafness

In three experiments, the efficiency in detecting fear-relevant and fear-irrelevant visual stimuli are compared. A visual search paradigm is used where participants are presented with matrices of different sizes (4 objects/9 objects) and must determine whether all objects are taken from the same category or whether there is a discrepant one. Results from all experiments were consistent with the threat-superiority effect. Participants were quicker when the target was threatening than when it was not. Other indicators confirmed that the detection of threatening targets involves more efficient processes (reduced slopes, absence of position effects). A crucial aspect of these experiments was the comparison of evolutionary-relevant (snakes, spiders, etc.) and modern (guns, syringes, etc.) threats. The threat-superiority effect was repeatedly found for both types of target. Stronger effects were sometimes observed for modern than for evolutionary-relevant threats. The implications for evolutionary explanations of the effect of fear on visual attention are discussed.     

‘We are the good guys but they are not bad’. In‐group positivity and cognitive performance in preschoolers

The general purpose of this study was to analyse the developmental relations between the early forms of ethnic attitudes, and the classification abilities of the young child. We designed new cognitive tasks within a detection paradigm adapted to preschoolers and attitudinal tasks that were presented as games in a computer screen. Participants were 75 majority‐group children of 3, 4, and 5 years of age. Children's preferences and positive/negative attitudes towards the in‐group (Spaniards) and three out‐groups (Latin‐Americans, Africans, and Asians) were measured. The results showed a remarkable preference and positivity for the in‐group, but not out‐group derogation. Children's cognitive performance, to a greater extent than their age, was positively associated with in‐group favouritism and positivity. On the other hand, we found some interesting differences and developmental changes in children's positive orientation to the out‐groups that are discussed in the last section.     

Is it dangerous? The role of an emotional visual search strategy and threat-relevant training in the detection of guns and knives

Counter-terrorism strategies rely on the assumption that it is possible to increase threat detection by providing explicit verbal instructions to orient people's attention to dangerous objects and hostile behaviours in their environment. Nevertheless, whether verbal cues can be used to enhance threat detection performance under laboratory conditions is currently unclear. In Experiment 1, student participants were required to detect a picture of a dangerous or neutral object embedded within a visual search display on the basis of an emotional strategy ‘is it dangerous?’ or a semantic strategy ‘is it an object?’. The results showed a threat superiority effect that was enhanced by the emotional visual search strategy. In Experiment 2, whilst trainee police officers displayed a greater threat superiority effect than student controls, both groups benefitted from performing the task under the emotional than semantic visual search strategy. Manipulating situational threat levels (high vs. low) in the experimental instructions had no effect on visual search performance. The current findings provide new support for the language-as-context hypothesis. They are also consistent with a dual-processing account of threat detection involving a verbally mediated route in working memory and the deployment of a visual template developed as a function of training.     

Reasoning and concurrent timing: a study of the mechanisms underlying the effect of emotion on reasoning

Negative emotions typically have an adverse effect on reasoning, especially analytic or logical reasoning. This effect can be explained using an attentional framework in which emotion detracts limited-capacity cognitive resources which are required for reasoning. Another possibility is that the effect of emotion on reasoning is mediated by arousal, as previous research has shown that physiological arousal can be associated with decreased reasoning performance. In this research, we used a dual-task paradigm combining a syllogistic reasoning task and a time production task. Prospective timing allows to disentangle the effects of attention and arousal: time productions should lengthen if emotion takes up cognitive resources that are therefore not available for timing, whereas time productions should shorten if emotional reasoning results from increased arousal. Results from two experiments confirm the adverse impact of emotion on logical reasoning performance. Reasoning about emotional contents led to lengthened time productions, which suggests that the capture of limited cognitive resources is the main factor accounting for the adverse effect of emotion on reasoning and not arousal.     

Scene memory is more detailed than you think: the role of categories in visual long-term memory

Observers can store thousands of object images in visual long-term memory with high fidelity, but the fidelity of scene representations in long-term memory is not known. Here, we probed scene-representation fidelity by varying the number of studied exemplars in different scene categories and testing memory using exemplar-level foils. Observers viewed thousands of scenes over 5.5 hr and then completed a series of forced-choice tests. Memory performance was high, even with up to 64 scenes from the same category in memory. Moreover, there was only a 2% decrease in accuracy for each doubling of the number of studied scene exemplars. Surprisingly, this degree of categorical interference was similar to the degree previously demonstrated for object memory. Thus, although scenes have often been defined as a superset of objects, our results suggest that scenes and objects may be entities at a similar level of abstraction in visual long-term memory.     

Microswitch-based programs for persons with multiple disabilities: an overview of some recent developments

Persons with multiple disabilities are often unable to interact with their environment due to their limited response repertoire. Microswitch programs are designed to help them control environmental events, generally preferred stimulation, through simple (feasible) responses. To make microswitch programs a more widely usable and relevant resource for intervention with these persons, a number of new developments were pursued in recent years. This paper examines three of those developments as specifically addressed in our research activity, namely, (a) assessment of new, nontypical responses and matching microswitches, (b) fostering of multiple responses and exercise of choice, and (c) targeting of habilitative and clinical (therapeutic) objectives. The encouraging outcomes of these developments are reviewed in relation to their potentially wide implications for daily practice and the need of additional developments in the area.     

The Briefest of Glances: The Time Course of Natural Scene Understanding

ABSTRACT— What information is available from a brief glance at a novel scene? Although previous efforts to answer this question have focused on scene categorization or object detection, real-world scenes contain a wealth of information whose perceptual availability has yet to be explored. We compared image exposure thresholds in several tasks involving basic-level categorization or global-property classification. All thresholds were remarkably short: Observers achieved 75%-correct performance with presentations ranging from 19 to 67 ms, reaching maximum performance at about 100 ms. Global-property categorization was performed with significantly less presentation time than basic-level categorization, which suggests that there exists a time during early visual processing when a scene may be classified as, for example, a large space or navigable, but not yet as a mountain or lake. Comparing the relative availability of visual information reveals bottlenecks in the accumulation of meaning. Understanding these bottlenecks provides critical insight into the computations underlying rapid visual understanding.