Does evaluative learning rely on the perception of contingency?: manipulating contingency and US density during evaluative conditioning

An experiment is reported studying the impact of objective contingency and contingency judgments on cross-modal evaluative conditioning (EC). Both contingency judgments and evaluative responses were measured after a contingency learning task in which previously neutral sounds served as either weak or strong predictors of affective pictures. Experimental manipulations of contingency and US density were shown to affect contingency judgments. Stronger contingencies were perceived with high contingency and with low US density. The contingency learning task also produced a reliable EC effect. The magnitude of this effect was influenced by an interaction of statistical contingency and US density. Furthermore, the magnitude of EC was correlated with the subjective contingency judgments. Taken together, the results imply that propositional knowledge about the CS-US relationship, as reflected in contingency judgments, moderates evaluative learning. The data are discussed with respect to different accounts of EC.     

The use of virtual reality for episodic memory assessment: effects of active navigation

Episodic memory was assessed using Virtual Reality (VR). Forty-four (44) subjects visualized a target virtual apartment containing specific objects in each room. Then they visualized a second virtual apartment comprised of specific objects and objects shared by the two apartments. Subjects navigated in the virtual apartments in one of the following two conditions: active and passive. Four main episodic memory components were scored from the VR exposures: (1) learning effect; (2) active forgetting effect; (3) strategies at encoding and at retrieval; and (4) false recognitions (FRs). The effect of navigation mode (active vs. passive) on each memory component was examined. Active subjects had better learning and retrieval (recognition hits) performances compared to passive subjects. A beneficial effect of active navigation was also observed on the source-based FR rates. Active subjects made fewer source-based FRs compared to passive subjects. These overall results for the effect of active navigation are discussed in terms of the distinction between item-specific and relational processing.     

Why do temporal generalization gradients change when people make decisions as quickly as possible?

Three experiments investigated temporal generalization performance under conditions in which participants were instructed to make their decisions as quickly as possible (speed), or were allowed to take their time (accuracy). A previous study (Klapproth & Müller, 2008) had shown that under speeded conditions people were more likely to confuse durations shorter than the standard with the standard than in the accuracy conditions, and a possible explanation of this result is that longer stimulus durations are "truncated" (i.e., people make a judgement about them before they have terminated, thereby shortening their effective duration) and that these truncated durations affect the standard used for the task. Experiment 1 investigated performance under speed and accuracy conditions when comparison durations were close to the standard or further away. No performance difference was found as a function of stimulus spacing, even though responses occurred on average before the longest durations had terminated, but this lack of effect was attributed to "task difficulty" effects changing decision thresholds. In Experiment 2, the standard duration was either the longest or the shortest duration in the comparison set, and differences between speed and accuracy groups occurred only when the comparisons were longer than the standard, supporting the "truncation" hypothesis. A third experiment showed that differences between speed and accuracy groups only occurred if some memory of the standard that was valid for more than one trial was used. In general, the results suggest that the generalization gradient shifts in speeded conditions occur because of truncation of longer comparison durations, which influences the effective standard used for the task.     

Response priming driven by local contrast, not subjective brightness

We demonstrate qualitative dissociations of brightness processing in visuomotor priming and conscious vision. Speeded keypress responses to the brighter of two luminance targets were performed in the presence of preceding dark and bright primes (clearly visible and flanking the targets) whose apparent brightness values were enhanced or attenuated by a visual illusion. Response times to the targets were greatly affected by consistent versus inconsistent arrangements of the primes, relative to the targets (response priming). Priming effects could systematically contradict subjective brightness matches, such that one prime could appear brighter than the other but could prime as if it were darker. Systematic variation of the illusion showed that response-priming effects depended only on local flanker-background contrast, not on the subjective appearance of the flankers. Our findings suggest that speeded motor responses, as opposed to conscious perceptual judgments, access an early phase of lightness and brightness processing prior to full lightness constancy.     

Aktuelle Aspekte des Gefängnissuizids

Suicides present a major complication during imprisonment and contribute essentially to the high mortality rate of prisoners. All international studies found increased suicide rates among prisoners in comparison to the general population. This article reviews general and individual risk factors for suicide in prison and possible contributing specific stress factors during imprisonment. The main results of the analysis of the European Annual Prison Statistics from 1997 to 2007 are presented referring to macrostructural determining risk factors for suicide in prison. Measurements and prevention strategies are briefly discussed.     

A diffusion model explanation of the worst performance rule for reaction time and IQ

The worst performance rule for cognitive tasks [Coyle, T.R. (2003). IQ, the worst performance rule, and Spearman's law: A reanalysis and extension. Intelligence, 31, 567-587] in which reaction time is measured is the result that IQ scores correlate better with longer (i.e., 0.7 and 0.9 quantile) reaction times than shorter (i.e., 0.1 and 0.3 quantile) reaction times. We show that this pattern of correlations can be predicted by the diffusion model [Ratcliff, R. (1978). A theory of memory retrieval. Psychological Review, 85, 59-108], in two ways: either assuming that the rate of accumulation of information toward a decision is higher for higher IQ subjects or assuming that the criterial amounts of information they require before a decision are lower. Importantly, the model explains both reaction times and accuracy, so the two possibilities can be distinguished.     

Style follows content: on the microgenesis of art perception

Despite fruitful research in experimental aesthetics, the dynamics of aesthetics, i.e., the processes involved in art perception, have received little attention. Concerning representational art, two aspects seem most important in this respect: style and content. In two experiments, we examined the dynamics of processing of style and content by means of the microgenetic approach. This approach systematically varies perceptual conditions to find out about the stages involved in the formation of percepts – their microgenesis. Participants gave similarity ratings for pairs of pictures that were fully crossed in style (artist) and content (motif). Presentation times were systematically varied between 10, 50, 202 and 3000 ms (Experiment 1) plus unlimited presentation time (Experiment 2). While effects of content were present at all presentation times, effects of style were traceable from 50 ms onwards. The results show clear differences in the microgenesis of style and content, suggesting that in art perception style follows content.     

The rubber hand illusion depends on a congruent mapping between real and artificial fingers

The rubber hand illusion (RHI), in which a visible artificial hand is touched (or moves) synchronously with the participant's unseen own hand, indicates that body representations can undergo rapid changes. While several constraints for this illusion have been described, some reports highlight a remarkable flexibility of body representations, even contradicting a priori assumptions regarding body appearance and anatomy (e.g., the subjective embodiment of a third arm).     

Deriving auditory features from triadic comparisons

A feature-based representation of auditory stimuli is proposed and tested experimentally. Within a measurement-theoretical framework, it is possible to decide whether a representation of subjective judgments with a set of auditory features is possible and how unique such a representation is. Furthermore, the method avoids confounding listeners' perceptual and verbal abilities, in that it strictly separates the process of identifying auditory features from labeling them. The approach was applied to simple synthetic sounds with well-defined physical properties (narrow-band noises and complex tones). For each stimulus triad, listeners had to judge whether the first two sounds displayed a common feature that was not shared by the third, by responding with a simple "yes" or "no." Because of the high degree of consistency in the responses, feature structures could be obtained for most of the subjects. In summary, the proposed procedure constitutes a supplement to the arsenal of psychometric methods with the main focus of identifying the type of sensation itself, rather than of measuring its threshold or magnitude.