Forgetting to forget: On the duration of voluntary suppression of neutral and emotional memories

Can we control the content of our memory and forget what we do not want to think about by an act of will? If so, is forgetting temporary or permanent, and is it independent of the nature of what we wish to forget? Using Anderson and Green’s (2001) “think/no-think” paradigm with neutral and emotional nouns, we found in agreement with other studies that memory for neutral words was reduced instantly upon repeated attempts at suppression. However, the effect was temporary and vanished after a period of one week, which strongly suggests that intended memory suppression interferes with immediate retrieval but does not lead to long-term forgetting. Furthermore, the amount of training that clearly reduced immediate recall of neutral items did not at all reduce recall of emotional items. This finding is in accordance with the notion that emotional items have a higher degree of salience and tend to attract more attention than neutral items.     

Ambulante psychosomatische Nachsorge und soziale Ungleichheit

Background

Social inequality is not considered to be an influential factor in studies regarding the effectiveness of psychosomatic rehabilitation. Nevertheless, there is evidence of lower accessibility of patients with psychiatric disorders when they have a lower educational or socio-economic status.

Material and methodology

A total of 214 participants of out-patient aftercare were divided into two groups according to education and socio-economic status and compared with a control group (n=121). Changes in symptom load and the ability to manage daily life 1 year after release from in-patient rehabilitation treatment were examined in a repeated measures design.

Results

The treatment group was able to reduce symptom loads as well as improve their daily life skills. However, mainly participants with a higher education level and higher social-economic status benefited from treatment.

Conclusion

Social inequality in aftercare groups requires more targeted sociomedical consulting and an intensified case management. At the same time management of the group should not take the highest level as a general guideline.     

Optimizing subjective measures of consciousness

Dienes and Seth (2010) conclude that confidence ratings and post-decision wagering are two comparable and recommendable measures of conscious experience. In a recently submitted paper, we have however found that both methods are problematic and seem less suited to measure consciousness than a direct introspective measure.Here, we discuss the methodology and conclusions put forward by Dienes and Seth, and why we think the two experiments end up with so different recommendations.     

Decreased parahippocampal activity in associative priming: evidence from an event-related fMRI study

In recent years, there has been intense debate on the neural basis of associative priming, particularly on the role of the medial temporal lobe (MTL) in retrieving associative information without awareness. In this study, event-related fMRI was used while healthy subjects performed a perceptual identification task on briefly presented unrelated word pairs and an associative recognition memory task. Contamination of priming by explicit memory was successfully controlled, as associative priming and explicit memory were dissociated on the behavioral level. The fMRI results showed a functional dissociation within the MTL with respect to associative priming effects. The right parahippocampal cortex, but not the hippocampus, showed decreased activation for old vs. new pairs and old vs. recombined pairs (associative priming). The bilateral hippocampus and the right parahippocampal cortex were involved in explicit associative memory. These data provide evidence that subregions of the MTL participate in associative priming even when explicit involvement was controlled. Thus, different regions within the MTL play distinct roles in explicit and implicit associative memory.     

Familiarity supports associative recognition memory for face stimuli that can be unitised: Evidence from receiver operating characteristics

According to dual-process models, associative recognition memory mainly relies on recollection without benefiting from familiarity. This study investigates the circumstances under which familiarity may support associative recognition judgements by comparing recognition memory for arbitrarily paired items (i.e., pairs of face stimuli depicting two different persons; interitem associations) with recognition memory for pairs of items that are highly overlapping and can be unitised into a coherent whole (i.e., pairs of physically different but very similar face stimuli depicting the same person; intraitem associations). Estimates of familiarity and recollection were derived from receiver operating characteristics. Consistent with the hypothesis that familiarity is able to support associative recognition memory, but only when the to-be-associated stimuli can be unitised, results from two experiments revealed higher familiarity estimates for intra- compared to interitem associations. By contrast, recollection for recombined pairs was higher for inter- compared to intraitem associations. We propose a hypothetical model on how intraitem associations may benefit from familiarity.     

Repeating a strongly masked stimulus increases priming and awareness

Previous studies [Marcel, A. J. (1983). Conscious and unconscious perception: Experiments on visual masking and word recognition. Cognitive Psychology, 15(2), 197–237; Wentura, D., & Frings, C. (2005). Repeated masked category primes interfere with related exemplars: New evidence for negative semantic priming. Journal of Experimental Psychology: Learning, Memory, and Cognition, 31(1), 108–120] suggested that repeatedly presenting a masked stimulus improves priming without increasing perceptual awareness. However, neural theories of consciousness predict the opposite: Increasing bottom-up strength in such a paradigm should also result in increasing availability to awareness. Here, we tested this prediction by manipulating the number of repetitions of a strongly masked digit. Our results do not replicate the dissociation observed in previous studies and are instead suggestive that repeating an unconscious and attended masked stimulus enables the progressive emergence of perceptual awareness.     

A latent state-trait anxiety model and its application to determine consistency and specificity coefficients

Abstract

In the present study the consistency model (Steyer, 1987) was applied to data gathered with the German version of the State-Trait Anxiety Inventory (Laux, Glanzmann, Schaffner, and Spielberger, 1981). The questionnaire was presented twice to 64 university students with an interval of two months between first and second testing. The consistency and specificity coefficients, estimated by LISREL (Jöreskog and Sörbom, 1984), support the state-trait distinction. The state variables have high specificity and consistency coefficients; the trait variables, in contrast, have high consistency coefficients but low or even negligible specificity coefficients. The discussion points out the advantages of the consistency model over the stability model; the most important advantage is that the theoretical structure of the consistency model is more appropriate for the type of application considered. It contains a state factor for each occasion of measurement and a trait factor common to all occasions of measurement. In the stability model, only latent states, but no latent traits occur. Consistency, specificity, and reliability can be identified as proportions of variance determined by latent variables specified in the model. Therefore, data analysis provides statistics concerning the practical significance of the trait and of the effects of situations and/or interactions.     

Gamma activity in human EEG is related to highspeed memory comparisons during object selective attention

Among the most important processes of the brain in order to correctly perceive the outside world and act within it are binding, attention, and memory. All three functional mechanisms have been associated with brain activity in the gamma frequency range. It needs to be clarified, however, which subprocesses within the gamma frequency range relate to which perceptual or cognitive functions. In a visual discrimination task, we used Kanizsa figures whose constituent inducer disks need to be bound together to perceive the illusory contours. By a variation of the task requirements we manipulated the allocation of object selective attention as compared to a previous study. One out of four objects had to be detected. This detection process requires the comparison of two object dimensions (form and collinearity) with a working memory template. In order to get behavioural and electrophysiological measures, EEG and reaction times were recorded from 16 and 10 subjects, respectively. We demonstrated that the early evoked gamma activity reflects the process of allocating attention to a selected object as early as 50-150 ms after stimulus onset. We propose that the underlying mechanism is a high-speed memory comparison. In addition, we show that this early gamma activity also determines the reaction times needed to respond to the different stimuli.     

Theory and Analysis of Total,Direct, and Indirect Causal Effects

Mediation analysis, or more generally models with direct and indirect effects, are commonly used in the behavioral sciences. As we show in our illustrative example, traditional methods of mediation analysis that omit confounding variables can lead to systematically biased direct and indirect effects, even in the context of a randomized experiment. Therefore, several definitions of causal effects in mediation models have been presented in the literature (Baron &; Kenny, 1986 Baron, R.M., &; Kenny, D.A. (1986). The moderator-mediator variable distinction in social psychological research: Conceptual, strategic and statistical considerations. Journal of Personality and Social Psychology, 51, 1173–1182. doi:10.1037/0022-3514.51.6.1173[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Imai, Keele, &; Tingley, 2010 Imai, K., Keele, L., &; Tingley, D. (2010). A general approach to causal mediation analysis. Psychological Methods, 15, 309–334. doi:10.1037/a0020761[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]; Pearl, 2012 Pearl, J. (2012). The causal mediation formula: A guide to the assessment of pathways and mechanisms. Prevention Science, 13, 426–436. doi:10.1007/s11121-011-0270-1[Crossref], [PubMed], [Web of Science ®] , [Google Scholar]). We illustrate the stochastic theory of causal effects as an alternative foundation of causal mediation analysis based on probability theory. In this theory we define total, direct, and indirect effects and show how they can be identified in the context of our illustrative example. A particular strength of the stochastic theory of causal effects are the causality conditions that imply causal unbiasedness of effect estimates. The causality conditions have empirically testable implications and can be used for covariate selection. In the discussion, we highlight some similarities and differences of the stochastic theory of causal effects with other theories of causal effects.