Probabilities on Sentences in an Expressive Logic

Automated reasoning about uncertain knowledge has many applications. One difficulty when developing such systems is the lack of a completely satisfactory integration of logic and probability. We address this problem directly. Expressive languages like higher-order logic are ideally suited for representing and reasoning about structured knowledge. Uncertain knowledge can be modeled by using graded probabilities rather than binary truth values. The main technical problem studied in this paper is the following: Given a set of sentences, each having some probability of being true, what probability should be ascribed to other (query) sentences? A natural wish-list, among others, is that the probability distribution (i) is consistent with the knowledge base, (ii) allows for a consistent inference procedure and in particular (iii) reduces to deductive logic in the limit of probabilities being 0 and 1, (iv) allows (Bayesian) inductive reasoning and (v) learning in the limit and in particular (vi) allows confirmation of universally quantified hypotheses/sentences. We translate this wish-list into technical requirements for a prior probability and show that probabilities satisfying all our criteria exist. We also give explicit constructions and several general characterizations of probabilities that satisfy some or all of the criteria and various (counter)examples. We also derive necessary and sufficient conditions for extending beliefs about finitely many sentences to suitable probabilities over all sentences, and in particular least dogmatic or least biased ones. We conclude with a brief outlook on how the developed theory might be used and approximated in autonomous reasoning agents. Our theory is a step towards a globally consistent and empirically satisfactory unification of probability and logic.     

Synesthetic grapheme-color percepts exist for newly encountered Hebrew,Devanagari, Armenian and Cyrillic graphemes

Grapheme-color synesthetes experience color, not physically present, when viewing symbols. Synesthetes cannot remember learning these associations. Must synesthetic percepts be formed during a sensitive period? Can they form later and be consistent? What determines their nature? We tested grapheme-color synesthete, MC2, before, during and after she studied Hindi abroad. We investigated whether novel graphemes elicited synesthetic percepts, changed with familiarity, and/or benefited from phonemic information. MC2 reported color percepts to novel Devanagari and Hebrew graphemes. MC2 monitored these percepts over 6 months in a Hindi-speaking environment. MC2 and synesthete DN, reported synesthetic percepts for Armenian graphemes, or Cyrillic graphemes + phonemes over time. Synesthetes, not controls, reported color percepts for novel graphemes that gained consistency over time. Phonemic information did not enhance consistency. Thus, synesthetes can form and consolidate percepts to novel graphemes as adults. These percepts may depend on pre-existing grapheme-color relationships but they can flexibly shift with familiarity.     

Beyond test anxiety: Development and validation of the test emotions questionnaire (TEQ)

Measures of test emotions other than test anxiety are lacking. In a series of six studies, we developed a multi-scale questionnaire assessing test-related joy, hope, pride, relief, anger, anxiety, shame, and hopelessness (Test Emotions Questionnaire, TEQ). Consisting of subscales measuring affective, cognitive, physiological, and motivational emotion components, the scales can be used to identify both trait and state test emotions, and are available in German- and English-language versions. Using a rational-empirical strategy of test construction, we first developed theoretical models of the component structures, antecedents, and effects of different test emotions. We then conducted two exploratory, qualitative studies on the occurrence and structures of these emotions. Finally, based on theory and our exploratory data, we constructed, analyzed, and revised the scales of the TEQ in four quantitative studies. Findings of correlational and confirmatory factor analysis indicate that the scales are reliable, structurally valid in terms of representing different test emotions and components within emotions, and externally valid in terms of correlating significantly with personality, learning, academic achievement, and perceived health problems. Many of these correlations proved to be stronger for test emotions other than anxiety, implying that test anxiety is neither the only relevant test emotion, nor necessarily the most important one.     

Strategies in relational inference

Three experiments are reported in which the relationships between task format, item type, and strategy usage were investigated for a two-dimensional relational inference task. Contrary to past findings with linear syllogisms, it was found that parallel presentation (presenting problem statements simultaneously) did not result in any increased use of deduction rule processes compared with serial presentation (presenting problem statements individually). Instead, the results suggested that mental models were used by the majority of subjects, and that multiple models were more likely to be constructed with parallel presentation. It is proposed that, in general, multiple model construction will be more frequent for deduction tasks where the cognitive load is relatively low. Hence, contrary to suggestions by Polk and Newell (1995), reasoning in this way appears to be prevalent and highly robust—where supported by task format—even where the use of this strategy is disadvantageous.     

Leaders’ receptivity to subordinates’ creative input: The role of achievement goals and composition of creative input

We identified leaders’ achievement goals and composition of creative input as important factors that can clarify when and why leaders are receptive to, and supportive of, subordinates’ creative input. As hypothesized, in two experimental studies, we found that relative to mastery goal leaders, performance goal leaders were less receptive to subordinates’ voiced creative input. In Study 1, we further showed that image threat appraisal and learning opportunity appraisal mediated this effect. In Study 2, we demonstrated that when merely creative ideas were expressed by the subordinate, performance goal leaders responded like mastery goal leaders. However, as in Study 1, performance goal leaders were less receptive to, and less supportive of, subordinates’ creative input than mastery goal leaders when the composition of subordinates’ creative input included both problem identifications and creative ideas.     

Activity experiences shape perceived fitness trajectories: Results from a 6-month randomized controlled trial in older women

ABSTRACT

In this study we addressed the subjective benefits of activity interventions that were designed to improve cognitive fitness in old age. Two hundred and fifty-nine women (aged 70–93 years) were randomized to participate in an exercise or a computer course or a control condition for 6 months. Subjective ratings of the perceived change of cognitive and physical fitness components were captured before, during, after the intervention interval, and at a 10-month follow-up. Positive and negative affect levels and objective cognitive fitness parameters served as possible covariates. Multilevel modeling revealed that the computer group rated memory and concentration as having improved at 4 months and again at 6 months. The exercise group, in contrast, perceived physical capacities as maintained or improved. The characteristics of the activity experience seem to determine the perceived fitness changes. We conclude that actual learning experiences improve one's self-concept of abilities.     

School enrolment and executive functioning: A longitudinal perspective on developmental changes,the influence of learning context,and the prediction of pre-academic skills

The present two-year longitudinal study addressed developmental changes in different aspects of executive functioning (i.e., inhibition, updating, and cognitive flexibility) in a sample of 264 children aged between 5 and 7 years. Of special interest were issues of developmental progression over time, the influence of learning context and the predictive power of executive functions and school context for emerging academic skills. The results revealed pronounced improvements in all executive measures, both over time and as a function of age. For the learning context, small and age-dependent effects on executive skills were found. Inhibition uniquely contributed to the prediction of aspects of emerging academic skills, over and above chronological age and language skills.     

Orthographic facilitation in oral vocabulary acquisition

An experiment investigated whether exposure to orthography facilitates oral vocabulary learning. A total of 58 typically developing children aged 8–9 years were taught 12 nonwords. Children were trained to associate novel phonological forms with pictures of novel objects. Pictures were used as referents to represent novel word meanings. For half of the nonwords children were additionally exposed to orthography, although they were not alerted to its presence, nor were they instructed to use it. After this training phase a nonword–picture matching posttest was used to assess learning of nonword meaning, and a spelling posttest was used to assess learning of nonword orthography. Children showed robust learning for novel spelling patterns after incidental exposure to orthography. Further, we observed stronger learning for nonword–referent pairings trained with orthography. The degree of orthographic facilitation observed in posttests was related to children's reading levels, with more advanced readers showing more benefit from the presence of orthography.     

Improved intertask coordination after extensive dual-task practice

This study examines whether an improved intertask coordination skill is acquired during extensive dual-task training and whether it can be transferred to a new dual-task situation. Participants practised a visual–manual task and an auditory–vocal task. These tasks were trained in two groups matched in dual-task performance measures before practice: a single-task practice group and a hybrid practice group (including single-task and dual-task practice). After practice, the single-task practice group was transferred to the same dual-task situation as that for the hybrid practice group (Experiment 1), both groups were transferred to a dual-task situation with a new visual task (Experiment 2), and both groups were transferred to a dual-task situation with a new auditory task matched in task difficulty (Experiment 3). The results show a dual-task performance advantage in the hybrid practice group over the single-task practice group in the practised dual-task situation (Experiment 1), the manipulated visual-task situation (Experiment 2), and the manipulated auditory-task situation (Experiment 3). In all experiments, the dual-task performance advantage was consistently found for the auditory task only. These findings suggest that extended dual-task practice improves the skill to coordinate two tasks, which may be defined as an accelerated switching operation between both tasks. This skill is relatively robust against changes of the component visual and auditory tasks. We discuss how the finding of task coordination could be integrated in present models of dual-task research.     

Bartlett's schema theory: The unreplicated “portrait d'homme” series from 1932

In 1932, Frederic Bartlett laid the foundation for the later schema theory. His key assumption of previous knowledge affecting the processing of new stimuli was illustrated in the famous “portrait d'homme” series. Sequenced reproductions of ambiguous stimuli showed progressive object-likeness. As Bartlett pointed out, activation of specific schemata, for instance “the face schema”, biases memory retrieval towards such schemata. In five experiments (Experiment 1, n?=?53; Experiment 2, n?=?177; Experiment 3, n?=?36; Experiment 4, n?=?6; Experiment 5, n?=?2), we tested several factors potentially influencing retrieval biases—for example, by varying the general procedure of reproduction (repeated vs. serial) and by omitting versus providing visual or semantic cues for activating face schemata. Participants inspected face-like stimuli with the caption “portrait of the human” and reproduced them repeatedly under specific conditions. None of the experiments revealed a systematic tendency towards Bartlett's described case, even when the participants were explicitly instructed to draw “a face” like the previously inspected one. In one of the “serial reproduction” experiments, we even obtained contrary effects with decreasing face-likeness over the reproduction generations. A close analysis of the original findings raises questions about the replicability of Bartlett's findings, qualifying the “portrait d'homme” series more or less as an illustrative example of the main idea of reconstructive memory.