Predictive coding explains binocular rivalry: an epistemological review

Binocular rivalry occurs when the eyes are presented with different stimuli and subjective perception alternates between them. Though recent years have seen a number of models of this phenomenon, the mechanisms behind binocular rivalry are still debated and we still lack a principled understanding of why a cognitive system such as the brain should exhibit this striking kind of behaviour. Furthermore, psychophysical and neurophysiological (single cell and imaging) studies of rivalry are not unequivocal and have proven difficult to reconcile within one framework. This review takes an epistemological approach to rivalry that considers the brain as engaged in probabilistic unconscious perceptual inference about the causes of its sensory input. We describe a simple empirical Bayesian framework, implemented with predictive coding, which seems capable of explaining binocular rivalry and reconciling many findings. The core of the explanation is that selection of one stimulus, and subsequent alternation between stimuli in rivalry occur when: (i) there is no single model or hypothesis about the causes in the environment that enjoys both high likelihood and high prior probability and (ii) when one stimulus dominates, the bottom-up, driving signal for that stimulus is explained away while, crucially, the bottom-up signal for the suppressed stimulus is not, and remains as an unexplained but explainable prediction error signal. This induces instability in perceptual dynamics that can give rise to perceptual transitions or alternations during rivalry.     

Social presence effects on the stroop task: Boundary conditions and an alternative account

Two studies investigated boundary conditions of an effect of social presence on the Stroop task and its interpretation in terms of an attentional view (P. Huguet, M. P. Galvaing, J. M. Monteil, & F. Dumas, 1999). In this view, social presence leads to attentional focusing, enhancing participants’ ability to screen out the distracting features of Stroop stimuli. As predicted, Stroop interference was found to be reduced by social presence, but an alternative account in which social presence exerts an effect on task selection received more support.     

Compensatory properties of visual information in the control of isometric force

This experiment investigated the effects of spatial (gain) and temporal (frequency) properties of visual feedback on the control of isometric force output. Participants performed an index finger isometric force production task with five different levels of visual gain and four feedback frequencies. There was a significant effect of gain on mean and standard deviation (SD) of the force output, whereas feedback frequency significantly affected the force SD and root-mean square error. Significant effects of gain and frequency and a gain X frequency interaction on the approximate entropy (ApEn) of the force revealed the effect of visual feedback uncertainty on the force fluctuation dynamics. The combined effects of the spatial and temporal properties of visual feedback on ApEn were approximated by a sum of quadratic functions, indicating their compensatory effect on the informational content of the dynamics of isometric force.     

Busy perceivers and ineffective suppression goals: a critical role for distracter thoughts

With limited cognitive resources, suppressing thoughts can be ineffective. The detrimental effects of cognitive load on suppression have typically been attributed to increased accessibility of avoided thoughts. However, little research has examined distracter thoughts and their contribution to these effects. In three studies, participants pursued suppression goals related to social judgments (e.g., avoid negative thoughts about a target's performance) with sufficient or diminished cognitive resources. Compared to suppressors not under cognitive load, suppressors under load drew more negative social inferences when pursuing a negative suppression goal and more positive inferences under a positive suppression goal; load did not similarly disrupt a concentration goal (i.e., focus on positive thoughts). Across studies, load reduced high-quality oppositely valenced distracter thoughts, and these distracter thoughts mediated the detrimental effects of load on social inferences. The discussion focuses on mechanisms underlying the effects of load on suppression, implications, and future directions for research on ironic processes.     

Effects of race on responses and response latencies in the weapon identification task: a test of six models

The authors consider six models of underlying process in the weapon identification task: The first two are response-time extensions of signal detection models; the last four, of the process dissociation model. Predictions for accuracy data, correct response latencies, and false response latencies are used to discriminate between models. In the present study, racial bias in responses and correct response latency was replicated. New findings were that the direction of bias was reversed in error latency and that errors were faster than correct responses. These findings rule out four models, in particular, the idea that race biases early perception and interpretation of targets. Implications for reducing errors in the weapon identification task and possibilities of discriminating between the remaining two models are discussed.     

The ‘elasticity’ of criminal evidence: a moderator of investigator bias

This study examined investigators' perceptions of the reliability of incriminating and exonerating evidence of different types. Police trainees in the role of investigators read the background of a homicide case and then received a piece of evidence that either confirmed or disconfirmed their prior suspicion against the suspect. Despite identical objective characteristics of the evidence, participants rated the disconfirming (vs. confirming) evidence as less reliable and generated more arguments to question its reliability. This asymmetrical scepticism was stronger for participants judging witness evidence, compared to DNA and photo evidence, supporting the hypothesis that different types of evidence vary in ‘elasticity’—the extent to which subjective interpretations can be justified. Interestingly, the observed effects were not limited to the specific evidence in the case, but also affected the ratings of the type of evidence in general, suggesting that reliability criteria for witness information are highly malleable and sensitive to contextual influences. Copyright © 2008 John Wiley & Sons, Ltd.     

Doppelte Wirklichkeiten

The paper describes phenomenological, psychodynamic, interpersonal and developmental aspects of shame affects and shame conflicts, the difference between the experience of shame and guilt, and assessment instruments for shame. The relationships between the experience of shame and family dynamics are presented on a conceptual and case material level. In both family systems and in individuals, shame protects privacy, intimacy and boundaries. Beyond this, families as private spheres can protect their members from exposure and shame. Shame is closely connected with the development of family self-images and the family feeling. As a result of these and family loyalty bonds, a borrowed feeling of shame can develop. The development of family myths and family secrets can be motivated by shame and by many defensive operations, which contribute to confusion and disturbances in the perception of the self and interpersonal relationships. These defences also appear in transference. An awareness of shame and loyalty can foster therapeutic change in family systems.     

Episodic future thought and its relation to remembering: evidence from ratings of subjective experience

The goal of the present study was to examine the hypothesis that the ability to construct vivid mental images of the future involves sampling the contents of memory. In two experiments, participants envisioned future scenarios occurring in contextual settings that were represented in memory in varying degrees of perceptual detail. In both experiments, detailed contextual settings were associated with more detailed images of the future and a stronger subjective experience. Our findings suggest that the contents of memory are routinely sampled during the construction of personal future scenarios.