The Logic of Theory Assessment

This paper starts by indicating the analysis of Hempel’s conditions of adequacy for any relation of confirmation (Hempel, 1945) as presented in Huber (submitted). There I argue contra Carnap (1962, Section 87) that Hempel felt the need for two concepts of confirmation: one aiming at plausible theories and another aiming at informative theories. However, he also realized that these two concepts are conflicting, and he gave up the concept of confirmation aiming at informative theories. The main part of the paper consists in working out the claim that one can have Hempel’s cake and eat it too — in the sense that there is a logic of theory assessment that takes into account both of the two conflicting aspects of plausibility and informativeness. According to the semantics of this logic, α is an acceptable theory for evidence β if and only if α is both sufficiently plausible given β and sufficiently informative about β. This is spelt out in terms of ranking functions (Spohn, 1988) and shown to represent the syntactically specified notion of an assessment relation. The paper then compares these acceptability relations to explanatory and confirmatory consequence relations (Flach, 2000) as well as to nonmonotonic consequence relations (Kraus et al., 1990). It concludes by relating the plausibility-informativeness approach to Carnap’s positive relevance account, thereby shedding new light on Carnap’s analysis as well as solving another problem of confirmation theory. A precursor of this paper has appeared as “The Logic of Confirmation and Theory Assessment” in L. Běhounek & M. Bílková (eds.), The Logica Yearbook 2004, Prague: Filosofia, 2005, 161–176.     

Lateralized cognition: asymmetrical and complementary strategies of pigeons during discrimination of the "human concept"

This study was aimed at revealing which cognitive processes are lateralized in visual categorizations of "humans" by pigeons. To this end, pigeons were trained to categorize pictures of humans and then tested binocularly or monocularly (left or right eye) on the learned categorization and for transfer to novel exemplars (Experiment 1). Subsequent tests examined whether they relied on memorized features or on a conceptual strategy, using stimuli composed of new combinations of familiar and novel humans and backgrounds (Experiment 2), whether the hemispheres processed global or local information, using pictures with different levels of scrambling (Experiment 3), and whether they attended to configuration, using distorted human figures (Experiment 4). The results suggest that the left hemisphere employs a category strategy and concentrates on local features, while the right hemisphere uses an exemplar strategy and relies on configuration. These cognitive dichotomies of the cerebral hemispheres are largely shared by humans, suggesting that lateralized cognitive systems already defined the neural architecture of the common ancestor of birds and mammals.     

Temporal integration of monocular images separated in time: stereopsis, stereoacuity, and binocular luster

We evaluated stereopsis and binocular luster using electronically controlled shutter glasses with alternating monocular stimulation. In Experiment 1, we used the standard method for testing stereoacuity to obtain a gradual measure of stereopsis. Stereo thresholds decreased with increasing alternating frequency of two monocular half-images without a delay between them. Increasing delays led to increasing thresholds. In Experiment 2, we compared stereopsis resulting from two monocular half-images of a random-dot stereogram and binocular luster with respect to the minimum alternating frequency of the two half-images and the maximum interocular delay that were tolerated without a breakdown of the impression. Below 3 Hz, no stereopsis occurred. Binocular luster was observed only above 10 Hz. The mean threshold of interocular delay for detecting the global figure in a random-dot stereogram was about 51 msec, but for binocular luster it was about 20 msec. Overall, temporal integration was better for stereopsis than for binocular luster.     

The role of first- and second-order stimulus features for human overt attention

When processing complex visual input, human observers sequentially allocate their attention to different subsets of the stimulus. What are the mechanisms and strategies that guide this selection process? We investigated the influence of various stimulus features on human overt attention--that is, attention related to shifts of gaze with natural color images and modified versions thereof. Our experimental modifications, systematic changes of hue across the entire image, influenced only the global appearance of the stimuli, leaving the local features under investigation unaffected. We demonstrated that these modifications consistently reduce the subjective interpretation of a stimulus as "natural" across observers. By analyzing fixations, we found that first-order features, such as luminance contrast, saturation, and color contrast along either of the cardinal axes, correlated to overt attention in the modified images. In contrast, no such correlation was found in unmodified outdoor images. Second-order luminance contrast ("texture contrast") correlated to overt attention in all conditions. However, although none of the second-order color contrasts were correlated to overt attention in unmodified images, one of the second-order color contrasts did exhibit a significant correlation in the modified images. These findings imply, on the one hand, that higher-order bottom-up effects--namely, those of second-order luminance contrast--may partially account for human overt attention. On the other hand, these results also demonstrate that global image properties, which correlate to the subjective impression of a scene being "natural," affect the guidance of human overt attention.     

Happiness: Classic Theory in the Light of Current Research

Happiness is an eternal concern of philosophy and social science. Several classic intuitions about happiness get some support by the results of modern empirical research, not least, expectations about positive effects of technological development and individualization. The data do not confirm dismal predictions about anomic unhappiness. Though social development and transformation is ambivalent, the overall balance seems to be positive in modern societies.     

Children's metamemorial judgments in an event recall task

Two studies were conducted in which two different indicators of metacognitive monitoring were investigated in a complex everyday memory task. In the first phase of each experiment, 8- and 10-year-olds as well as adults were shown a short event (video) and gave judgments of learning, that is, rated their certainty that they would later be able to recall specific details correctly. In the second phase of the experiments, participants underwent a memory interview about the event and in Study 2 also gave confidence judgments, that is, rated their certainty that the provided answers to the memory questions were correct. Results revealed significant influences of memory characteristics on monitoring in that delaying judgments and monitoring judgments concerning irretrievable information affected judgments of learning. From 8 years of age onward, there were relatively appropriate metamemorial monitoring abilities in both indicators. Moderate intraindividual consistency was found across the two measures of metacognitive monitoring, with a tendency toward higher consistency in older age groups. The results are discussed in terms of the adequacy of the underlying theoretical construct.     

How Does Your Doctor Talk with You? Preliminary Validation of a Brief Patient Self-Report Questionnaire on the Quality of Physician–Patient Interaction

The quality of physician–patient interaction is increasingly being recognized as an essential component of effective treatment. The present article reports on the development and validation of a brief patient self-report questionnaire (QQPPI) that assesses the quality of physician–patient interactions. Data were gathered from 147 patients and 19 physicians immediately after consultations in a tertiary care outpatient setting. The QQPPI displayed good psychometric properties, with high internal consistency and good item characteristics. The QQPPI total score showed variability between different physicians and was independent of patients’ gender, age, and education. The QQPPI featured high correlations with other quality-related measures and was not influenced by social desirability, or patients’ clinical characteristics. The QQPPI is a brief patient self-report questionnaire that allows assessment of the quality of physician–patient interactions during routine ambulatory care. It can also be used to evaluate physician communication training programs or for educational purposes.     

Laws, Ceteris Paribus Conditions, and the Dynamics of Belief

The characteristic difference between laws and accidental generalizations lies in our epistemic or inductive attitude towards them. This idea has taken various forms and dominated the discussion about lawlikeness in the last decades. Likewise, the issue about ceteris paribus conditions is essentially about how we epistemically deal with exceptions. Hence, ranking theory with its resources of defeasible reasoning seems ideally suited to explicate these points in a formal way. This is what the paper attempts to do. Thus it will turn out that a law is simply the deterministic analogue of a sequence of independent, identically distributed random variables. This entails that de Finetti's representation theorems can be directly transformed into an account of confirmation of laws thus conceived. This revised version was published online in July 2006 with corrections to the Cover Date.     

Varying the response code in the blindness to response-compatible stimuli

Previous work has indicated that action-control processes can specifically influence perceptual processes. The identification of a left- or right-pointing arrow is impaired when it appears during the preparation and execution of a compatible left-right keypress (Müsseler & Hommel, 1997a, b). The present study examines the role of the response-specifying cue in order to manipulate the coding of the action-control processes. Experiment 1 shows that the size of the perceptual impairment is not affected by whether the cue has high or little feature overlap with the to-be-performed response. Cues were omitted in Experiment 2 and participants generated their responses endogenously, but the perceptual impairment still occurred. Experiment 3 examines in more detail which feature of the response contributes to the effect. The results show that it needs both an intended action goal and a corresponding motor activity to bring about the perceptual impairment.