Visual distance estimation in static compared to moving virtual scenes

Visual motion is used to control direction and speed of self-motion and time-to-contact with an obstacle. In earlier work, we found that human subjects can discriminate between the distances of different visually simulated self-motions in a virtual scene. Distance indication in terms of an exocentric interval adjustment task, however, revealed linear correlation between perceived and indicated distances but with a profound distance underestimation. One possible explanation for this underestimation is the perception of visual space in virtual environments. Humans perceive visual space in natural scenes as curved, and distances are increasingly underestimated with increasing distance from the observer. Such spatial compression may also exist in our virtual environment. We therefore surveyed perceived visual space in a static virtual scene. We asked observers to compare two horizontal depth intervals, similar to experiments performed in natural space. Subjects had to indicate the size of one depth interval relative to a second interval. Our observers perceived visual space in the virtual environment as compressed, similar to the perception found in natural scenes. However, the nonlinear depth function we found can not explain the observed distance underestimation of visual simulated self-motions in the same environment.     

Intelligence and individual differences in becoming neurally efficient

Physiological approaches to human psychometric intelligence have shown a higher neural efficiency (i.e. less cortical activation) during cognitive performance in brighter subjects. The main aim of this study was to explore the relationship between intelligence and cortical activation patterns in the framework of the learning test concept. In 27 participants we assessed the topography and extent of cortical activation by means of event-related desynchronization (ERD) during reasoning tests in a pre-test--training--post-test design and related it to psychometric intelligence (measured by the German Leistungs-Prüf-System, LPS). Significant associations between intelligence and cortical activation patterns were exclusively found at anterior (frontal) recording sites, which corroborates the central role of the frontal lobe for higher-order cognitive functions. The hypothesized negative intelligence-activation correlation was observed only after the training, i.e. in the post-test, but not in the pre-test. More important, the decrease in cortical investment from pre-test to post-test correlated negatively with intelligence, indicating that the higher the subjects' general mental ability the larger the decrease in the amount of cortical activation. These findings suggest intelligence-related individual differences in becoming neurally efficient.     

How children remember neutral and emotional pictures: boundary extension in children's scene memories

Boundary extension is the tendency to remember more of a scene than was actually shown. The dominant interpretation of this memory illusion is that it originates from schemata that people construct when viewing a scene. Evidence of boundary extension has been obtained primarily with adult participants who remember neutral pictures. The current study addressed the developmental stability of this phenomenon. Therefore, we investigated whether children aged 10-12 years display boundary extension for neutral pictures. Moreover, we examined emotional scene memory. Eighty-seven children drew pictures from memory after they had seen either neutral or emotional pictures. Both their neutral and emotional drawings revealed boundary extension. Apparently, the schema construction that underlies boundary extension is a robust and ubiquitous process.     

Universal sex differences in the desire for sexual variety: tests from 52 nations, 6 continents,and 13 islands

Evolutionary psychologists have hypothesized that men and women possess both long-term and short-term mating strategies, with men's short-term strategy differentially rooted in the desire for sexual variety. In this article, findings from a cross-cultural survey of 16,288 people across 10 major world regions (including North America, South America, Western Europe, Eastern Europe, Southern Europe, Middle East, Africa, Oceania, South/Southeast Asia, and East Asia) demonstrate that sex differences in the desire for sexual variety are culturally universal throughout these world regions. Sex differences were evident regardless of whether mean, median, distributional, or categorical indexes of sexual differentiation were evaluated. Sex differences were evident regardless of the measures used to evaluate them. Among contemporary theories of human mating, pluralistic approaches that hypothesize sex differences in the evolved design of short-term mating provide the most compelling account of these robust empirical findings.     

Emotional facilitation of sensory processing in the visual cortex

A key function of emotion is the preparation for action. However, organization of successful behavioral strategies depends on efficient stimulus encoding. The present study tested the hypothesis that perceptual encoding in the visual cortex is modulated by the emotional significance of visual stimuli. Event-related brain potentials were measured while subjects viewed pleasant, neutral, and unpleasant pictures. Early selective encoding of pleasant and unpleasant images was associated with a posterior negativity, indicating primary sources of activation in the visual cortex. The study also replicated previous findings in that affective cues also elicited enlarged late positive potentials, indexing increased stimulus relevance at higher-order stages of stimulus processing. These results support the hypothesis that sensory encoding of affective stimuli is facilitated implicitly by natural selective attention. Thus, the affect system not only modulates motor output (i.e., favoring approach or avoidance dispositions), but already operates at an early level of sensory encoding.     

Validation of the German version of Cloninger's TPQ: Replication and correlations with stress coping, mood measures and drug use

The tridimensional personality questionnaire (TPQ) was developed by Cloninger (1986, 1987a) to measure the independent personality dimensions Novelty Seeking (NS), Harm Avoidance (HA) and Reward Dependence (RD). After having investigated the basic psychometric properties of a German version of the TPQ in a first study (Weyers et al., 1995), a new sample of 200 subjects was collected to investigate the reliability of the results of this first study and to add further validity data by including measures of stress coping, mood and drug use. In general, the results of the first study were replicated. The internal consistencies of the superscales NS, HA and RD were high, and a factor analysis of the TPQ subscales yielded some support for Cloninger's personality theory. Because of its strong correlations with Psychoticism, Extraversion, Impulsiveness and Sensation Seeking NS seems to tap an impulsivity factor while HA correlates with Neuroticism and Introversion and appears to measure a behavioral inhibition factor, the latter interpretation being supported by correlations between HA and some mood measures like anxiety and self-confidence. In addition, HA showed substantial positive correlations with coping strategies like Rumination, Resignation and Self-pity and substantial negative correlations with strategies like Self-aggrandizement by Comparison with Others and Positive Self-instructions, while the other two TPQ superscales hardly correlate with any of the coping strategies measured. With respect to drug use, only NS showed small but substantial bivariate correlations with the use of nicotine and psychodysleptics for the last 12 weeks and last 2 years. However, a configurational analysis of the TPQ superscales demonstrated that the type II alcoholism pattern proposed by Cloninger (high NS, low HA and low RD) was associated with a strong alcohol consumption.     

The robustness of communication of emotion via facial expression: Emotion recognition from photographs with deteriorated pictorial quality

This study

1 The studies reported here were conducted within the TELEMED project which is funded by the European Community within the RACE program.

examines whether the recognition of emotion from facial expressions is impaired by deterioration of spatial resolution, contrast resolution, and picture size. Eighty judges rated 65 stimuli under 11 conditions: Undistorted, reduced spatial resolution (three steps), reduced contrast resolution (three steps), reduced picture size (three steps), and a very ‘hard’ condition combining the severest spatial and contrast resolution. Variation in picture quality was achieved by using a digital video recorder. Recognition rate and intensity ratings were not significantly affected by variations in contrast resolution or picture size. The only significant reduction of recognition rate and intensity ratings resulted from reduction in spatial resolution, but only with the largest deterioration in such resolution. Results are discussed with respect to the fundamental importance of facial expressions in interaction and communication, and with respect to applications, such as tele-conferencing systems.     

Vocal cues in emotion encoding and decoding

This research examines the correspondence between theoretical predictions on vocal expression patterns in naturally occurring emotions (as based on the component process theory of emotion; Scherer, 1986) and empirical data on the acoustic characteristics of actors' portrayals. Two male and two female professional radio actors portrayed anger, sadness, joy, fear, and disgust based on realistic scenarios of emotion-eliciting events. A series of judgment studies was conducted to assess the degree to which judges are able to recognize the intended emotion expressions. Disgust was relatively poorly recognized; average recognition accuracy for the other emotions attained 62.8% across studies. A set of portrayals reaching a satisfactory level of recognition accuracy underwent digital acoustic analysis. The results for the acoustic parameters extracted from the speech signal show a number of significant differences between emotions, generally confirming the theoretical predictions.This research was supported by a grant from the Deutsche Forschungsgemeinschaft (Sche 156/8-5). The authors acknowledge collaboration of Westdeutscher Rundfunk, Cologne, in producing professional versions of actor emotion portrayals, and thank Kurt Balser, Theodor Gehm, Christoph Gierschner, Judy Hall, Ursula Hess, Alice Isen, and one anonymous reviewer for helpful comments and contributions.     

Simultaneous classical conditioning of two effector systems

The experiment reported here was an attempt to develop an experimental procedure for independent classical conditioning of two different response systems, the skin conductance response (SCR) and the eyelid response. In a differential conditioning design with human subjects (N = 50) two different unconditioned stimuli were used, a white noise (US1) and airpuff (US2). Two conditioned stimuli (CS11 and CS12) were paired with US1, and two other CSs (CS21 and CS22) were paired with US2. A special trial architecture was used to accomplish measurement of both anticipatory SCR and eyelid responses during each trial. Significant eyelid differentiation as well as significant SCR (especially second interval responses) differentiation developed.     

Component summation or configuration in human eyelid conditioning depends upon stimulus properties

The experiment reviewed here merges Garner's (1974) distinction of separable and integral stimulus properties with the field of Pavlovian eyelid conditioning with human subjects. According to one rule, two sets of stimuli (separable vs integral) were constructed. A differential compound conditioning procedure was used with one group of subjects being trained with a subset of the separable material and then tested with a new subset. The same procedure was used with a second group but with integral material. The experiment showed a reversal of conditioning effects, depending on the properties of stimuli. Separable compounds showed results as predicted by elementistic conditioning theories: the associative values of the elements summed up. With integral compounds, the associative values of the elements were irrelevant. Instead, integral compounds were processed and classified primarily on the basis of similarity.