Implicit sequence learning and conscious awareness

This paper uses the Process Dissociation Procedure to explore whether people can acquire unconscious knowledge in the serial reaction time task [Destrebecqz, A., & Cleeremans, A. (2001). Can sequence learning be implicit? New evidence with the Process Dissociation Procedure. Psychonomic Bulletin &Review, 8, 343-350; Wilkinson, L., & Shanks, D. R. (2004). Intentional control and implicit sequence learning. Journal of Experimental Psychology: Learning, Memory, and Cognition, 30, 354-369]. Experiment 1 showed that people generated legal sequences above baseline levels under exclusion instructions. Reward moved exclusion performance towards baseline, indicating that the extent of motivation in the test phase influenced the expression of unconscious knowledge. Experiments 2 and 3 revealed that even with reward, adding noise to the sequences or shortening training led to above-baseline exclusion performance, suggesting that task difficulty and the amount of training also affected the expression of unconscious knowledge. The results help resolve some current debates about the role of conscious awareness in sequence learning.     

Different Associations of Health Related Quality of Life with Pain,Psychological Distress and Coping Strategies in Patients with Irritable Bowel Syndrome and Inflammatory Bowel Disorder

The primary aim of this study was to measure psychological distress, pain severity, health related quality of life (QOL) and pain coping strategies in patients with irritable bowel syndrome (IBS) and ulcerative colitis (UC). A second aim was to determine the influence of somatic and psychological variables on health related QOL. Eighty-eight IBS and 66 UC patients completed the Irritable Bowel Syndrome Quality of Life Questionnaire (IBSQOL), Pain Severity Scale of West Haven Yale Multidimensional Pain Inventory (WHYMPY), Symptom Checklist-90-R (SCL-90-R) and Coping Strategies Questionnaire (CSQ). T-tests and GLM Analysis of Covariance were used for statistical analysis. IBS patients had significantly higher levels of psychological distress, pain severity and maladaptive pain coping strategies (catastrophization), and lower QOL than UC patients. Variance of QOL in IBS was explained for the most part by catastrophization (15%), then by psychological distress (8%), and for the less part by pain severity (5%). In UC, pain severity explained 21%, psychological distress 8%, and catastrophization 3% of the variance of QOL. These results suggest there are differences between IBS and UC patients in the role of physical and psychological factors in QOL and emphasize the importance of cognitive processes in IBS.     

Role of selective attention in artificial grammar learning

To investigate the role of selective attention in artificial grammar (AG) learning, participants were presented with “GLOCAL” strings—that is, chains of compound global and local letters. The global and local levels instantiated different grammars. The results of this experiment revealed that participants learned only the grammar for the level to which they attended. The participants were not even able to choose presented but unattended strings themselves. These results show that selective attention plays a critical role in AG learning.     

How does prior knowledge affect implicit and explicit concept learning?

Two experiments investigated the effect of prior knowledge on implicit and explicit learning. Implicit as opposed to explicit learning is sometimes characterized as unselective or purely statistical. During training, one group of participants was presented with category exemplars whose features could be tied together by integrative knowledge, whereas another group saw category exemplars with unrelated feature combinations. Half of the participants in each group learned these categories under a secondary-task condition (meant to discourage explicit learning), and the remaining half performed the categorization task under a single-task condition (meant to favour explicit learning). In a test phase, participants classified only the individual features of the training exemplars. Secondary- as opposed to single-task conditions impaired explicit but not implicit knowledge (as determined by subjective measures). Importantly, prior knowledge resulted in increased amounts of both implicit and explicit knowledge.     

Tailoring of interfaces in amorphous silicon–germanium multilayers on the atomic scale by ultra-high gravity

Amorphous Si/Ge multilayers containing diffuse interfaces have been prepared, heated in an ultra-centrifuge and subsequent interface structure modifications observed by X-ray reflectivity. The thickness of the Si/Ge and Ge/Si interface zones became asymmetrical owing to various effects occurring on the different atoms parallel to the direction of gravity-induced diffusion. The technique could prove useful for tuning physical (electronic, magnetic or optical) properties of layered structures.     

The time course of implicit and explicit concept learning

The present experiment investigated the development of implicit and explicit knowledge during concept learning. According to Cleeremans and Jiménez (2002), the content of a representation can be conscious only when the representation is of a sufficiently good quality; on this theory, increasing explicit and decreasing implicit knowledge might be expected with training. The view that implicit knowledge arises from compilation of explicit knowledge makes the opposite prediction. The present research tested these possibilities using subjective measures based on confidence ratings. One group of participants was presented with blocks of category exemplars that activated prior knowledge, whereas another group was presented with blocks of categories that did not elicit any useful prior knowledge. The results showed that, irrespective of the knowledge group participants were allocated to, explicit knowledge increased over the course of learning, whereas implicit knowledge either stayed the same or decreased, consistent with Cleeremans and Jiménez's prediction.     

Learning non-local dependencies

This paper addresses the nature of the temporary storage buffer used in implicit or statistical learning. Kuhn and Dienes [Kuhn, G., and Dienes, Z. (2005). Implicit learning of nonlocal musical rules: implicitly learning more than chunks. Journal of Experimental Psychology-Learning Memory and Cognition, 31(6) 1417-1432] showed that people could implicitly learn a musical rule that was solely based on non-local dependencies. These results seriously challenge models of implicit learning that assume knowledge merely takes the form of linking adjacent elements (chunking). We compare two models that use a buffer to allow learning of long distance dependencies, the Simple Recurrent Network (SRN) and the memory buffer model. We argue that these models - as models of the mind - should not be evaluated simply by fitting them to human data but by determining the characteristic behaviour of each model. Simulations showed for the first time that the SRN could rapidly learn non-local dependencies. However, the characteristic performance of the memory buffer model rather than SRN more closely matched how people came to like different musical structures. We conclude that the SRN is more powerful than previous demonstrations have shown, but it's flexible learned buffer does not explain people's implicit learning (at least, the affective learning of musical structures) as well as fixed memory buffer models do.     

Measuring consciousness: relating behavioural and neurophysiological approaches

The resurgent science of consciousness has been accompanied by a recent emphasis on the problem of measurement. Having dependable measures of consciousness is essential both for mapping experimental evidence to theory and for designing perspicuous experiments. Here, we review a series of behavioural and brain-based measures, assessing their ability to track graded consciousness and clarifying how they relate to each other by showing what theories are presupposed by each. We identify possible and actual conflicts among measures that can stimulate new experiments, and we conclude that measures must prove themselves by iteratively building knowledge in the context of theoretical frameworks. Advances in measuring consciousness have implications for basic cognitive neuroscience, for comparative studies of consciousness and for clinical applications.     

Intentional control based on familiarity in artificial grammar learning

It is commonly held that implicit learning is based largely on familiarity. It is also commonly held that familiarity is not affected by intentions. It follows that people should not be able to use familiarity to distinguish strings from two different implicitly learned grammars. In two experiments, subjects were trained on two grammars and then asked to endorse strings from only one of the grammars. Subjects also rated how familiar each string felt and reported whether or not they used familiarity to make their grammaticality judgment. We found subjects could endorse the strings of just one grammar and ignore the strings from the other. Importantly, when subjects said they were using familiarity, the rated familiarity for test strings consistent with their chosen grammar was greater than that for strings from the other grammar. Familiarity, subjectively defined, is sensitive to intentions and can play a key role in strategic control.     

Sphincter of Oddi dysfunction: Does Psychosocial Distress Play a Role?

Sphincter of Oddi dysfunction (SOD) is a functional gastrointestinal disorder characterized by pancreatobiliary-type of pain in the absence of organic abnormalities. The aim of this study was to investigate specific psychosocial predictors of functional outcome in a group of patients consecutively referred to a gastroenterological department for biliary-type of pain. Based on medical examination patients were divided into functional (SOD) and organic groups. Self-administered questionnaires regarding demographic characteristics, psychological distress (Symptom Check-List-90–R, [SCL-90-R]), severity of acute and chronic stress, level of subjective well-being and satisfaction with health were completed. The analyses were based on the logistic regression approach. In this sample, SOD patients were older than organic patients and more likely female. Logistic regression analysis showed that higher acute stress (i.e., main effect) was associated with a decreased likelihood of functional (SOD) outcome, whereas the combination of acute stress with chronic stress and the combination of acute stress with higher severity of psychopathology (i.e., interaction effect) was associated with an increased likelihood of functional (SOD) outcome. These findings suggest stressful life events in combination with certain psychological symptoms can play a role in the symptom presentation of patients with sphincter of Oddi dysfunction.