How owls structure visual information

Recent studies on perceptual organization in humans claim that the ability to represent a visual scene as a set of coherent surfaces is of central importance for visual cognition. We examined whether this surface representation hypothesis generalizes to a non-mammalian species, the barn owl (Tyto alba). Discrimination transfer combined with random-dot stimuli provided the appropriate means for a series of two behavioural experiments with the specific aims of (1) obtaining psychophysical measurements of figure–ground segmentation in the owl, and (2) determining the nature of the information involved. In experiment 1, two owls were trained to indicate the presence or absence of a central planar surface (figure) among a larger region of random dots (ground) based on differences in texture. Without additional training, the owls could make the same discrimination when figure and ground had reversed luminance, or were camouflaged by the use of uniformly textured random-dot stereograms. In the latter case, the figure stands out in depth from the ground when positional differences of the figure in two retinal images are combined (binocular disparity). In experiment 2, two new owls were trained to distinguish three-dimensional objects from holes using random-dot kinematograms. These birds could make the same discrimination when information on surface segmentation was unexpectedly switched from relative motion to half-occlusion. In the latter case, stereograms were used that provide the impression of stratified surfaces to humans by giving unpairable image features to the eyes. The ability to use image features such as texture, binocular disparity, relative motion, and half-occlusion interchangeably to determine figure–ground relationships suggests that in owls, as in humans, the structuring of the visual scene critically depends on how indirect image information (depth order, occlusion contours) is allocated between different surfaces. Electronic Publication     

Well-being and motivational person-environment fit: A time-sampling study of emotions

The report is based on the data of seven studies (altogether 188 persons varying in gender, age, and education level) with the author's time-sampling diary, by which the subjects record their momentary mood, the behaviour setting, other persons present, activities, causal attributions of experienced emotions, and affected motives about four times a day for a period of 30 days. For each pattern of four 16PF second-order factors (median split), the relative frequencies of references to six classes of motives (i.e. the personal motive profiles) and for each of 16 behaviour settings, the relative frequencies by which each of those motives was satisfied in the whole sample of persons (environmental motive profiles) were derived from the diary data. The degree of motivational person–environment fit (P–E fit; correlation of personal and environmental motive profiles) was calculated for each combination of personality structure and behaviour setting. As predicted, a person's well-being in a behaviour setting clearly depends on the motivational P–E fit which explains the intra-individual variance of well-being (across situations) and the intra-situational variance (across persons) in addition to the variance explained by emotional stability and extraversion.     

A modified proportional change model of attitude change by group discussion

The data of two experiments of dyadic group discussion have been reanalysed. An extended proportional change model was designed to explain the actual process of attitude change. The model is defined by two parameters. The first represents the impact of single pro-arguments and single con-arguments on the attitude or decision preference. The second describes the resistance to further change that increases with the distance from the initial position. It was hypothesized that the first parameter should be higher and the second lower, with a similar partner than with a dissimilar one. The prediction was confirmed for the first parameter only. A comparison of the extended proportional change model to related models concludes the report.     

Speech perception deficits in Parkinson's disease: underestimation of time intervals compromises identification of durational phonetic contrasts

Besides motor, vegetative, and cognitive signs, patients suffering from Parkinson's disease (PD) may show distinct perceptual deficits such as underestimation of time intervals extending across several seconds. Assuming this impairment also to affect the domain of tens of milliseconds, disrupted encoding of the acoustic speech signal with respect to segment durations conveying linguistic information must be expected. To test this hypothesis, 10 PD patients and matched controls performed an identification task using a series of 10 stimuli derived from the utterance "Boten" (/bo:tn/, 'messengers'; produced with nasal plosion) by exclusive manipulation of occlusion length (110-20 ms in steps of 10 ms). Under these conditions, word-medial silence cues the voicing category of the respective stop consonant. Seven PD subjects showed normal identification curves, i.e., categorized the shortest and longest stimuli with high probability each as the minimal pair cognates "Boden" and "Boten," respectively. In contrast, the remaining three patients labeled all items across the complete range of occlusion lengths as "Boden." A subsequent experiment found a horizontal shift of the identification curves toward larger signal durations (> 120 ms) in these three subjects. Bilateral cerebellar degeneration has been found to yield a different response pattern, i.e., near-chance level of performance. Considering recent information-processing models of scalar interval timing, striatal disorders seem to slow down an oscillatory pacemaker, whereas cerebellar dysfunctions may impair comparison of measured durations with stored reference memory traces.     

Implementation intentions and efficient action initiation.

Implementation intentions ("If I encounter Situation X, then I'll perform Behavior Y!") are postulated to instigate automatic action initiation. In 4 studies, the hypothesis was tested that implementation intentions lead to immediate action initiation once the specified situation is encountered, even under conditions of high cognitive load. First, individuals whose action control is known to be hampered by disruptive cognitive business, such as opiate addicts under withdrawal (Study 1) and schizophrenic patients (Study 2), benefited from forming implementation intentions. Second, the beneficial effect of implementation intentions was also found in 2 experiments with university students (Studies 3 and 4) in which cognitive load was experimentally induced by using dual task paradigms. Results of the 4 studies suggest that forming implementation intentions instigates immediate action initiation that is also efficient.     

Personality Traits (“Big Five”) and the Propensity to Political Protest: Alternative Models

In a representative panel study, citizens of Leipzig (East Germany) were interviewed in 1993 and 1996 about their incentives for and participation in political protest activities. Conscientiousness, neuroticism, agreeableness, openness to experience, and extraversion (the Big Five) were measured with 16 bipolar adjectives. The present report supplements a previous work of the authors that drew on the theories of rational choice and collective action and conceived of incentives as proximal causes and personality dispositions as distant causes of political protest. Based on structural equation modelling (SEM), the present article deals with the respondents' recurrent reports on protest incentives and protest acts as indicators of the latent construct protest propensity that is according to the predictions directly influenced by openness to experience (O+), agreeableness (A?), neuroticism (N?), and reciprocity orientation (N*E+) with 35% explained variance.     

Topografie der Jugenddelinquenz

The article shows that the registered juvenile delinquency has decreased in recent years. Serious violent crime partially exists, but this is only a small part of the overall juvenile delinquency. Forms of appearance of these violent crimes are outlined. With the help of a dark field study it is illustrated that there is a great variety of delinquency among young people. There are young people showing mostly law-abiding behavior, infrequent offenders and a group with a significant burden of crimes.     

Small on the left,large on the right: numbers orient visual attention onto space in preverbal infants

Numbers are represented as ordered magnitudes along a spatially oriented number line. While culture and formal education modulate the direction of this number–space mapping, it is a matter of debate whether its emergence is entirely driven by cultural experience. By registering 8–9‐month‐old infants’ eye movements, this study shows that numerical cues are critical in orienting infants’ visual attention towards a peripheral region of space that is congruent with the number's relative position on a left‐to‐right oriented representational continuum. This finding provides the first direct evidence that, in humans, the association between numbers and oriented spatial codes occurs before the acquisition of symbols or exposure to formal education, suggesting that the number line is not merely a product of human invention.     

Predicting post-event processing in social anxiety disorder following two prototypical social situations: State variables and dispositional determinants

This study investigated self-reported state (anxiety, physical symptoms, cognitions, internally focused attention, safety behaviors, social performance) and trait (social anxiety, depressive symptoms, dysfunctional self-consciousness) predictors of post-event processing (PEP) subsequent to two social situations (interaction, speech) in participants with a primary diagnosis of social anxiety disorder (SAD) and healthy controls (HC). The speech triggered significantly more intense PEP, especially in SAD. Regardless of the type of social situation, PEP was best predicted by situational anxiety and dysfunctional cognitions among the state variables. If only trait variables were considered, PEP following both situations was accounted for by trait social anxiety. In addition, dysfunctional self-consciousness contributed to PEP-speech. If state and trait variables were jointly considered, for both situations, situational anxiety and dysfunctional cognitions were confirmed as the most powerful PEP predictors above and beyond trait social anxiety (interaction) and dysfunctional self-consciousness (speech). Hence, PEP as assessed on the day after a social situation seems to be mainly determined by state variables. Trait social anxiety and dysfunctional self-consciousness also significantly contribute to PEP depending on the type of social situation. The present findings support dysfunctional cognitions as a core cognitive mechanism for the maintenance of SAD. Implications for treatment are discussed.