The cognitive and neural architecture of sequence representation

The authors theorize that 2 neurocognitive sequence-learning systems can be distinguished in serial reaction time experiments, one dorsal (parietal and supplementary motor cortex) and the other ventral (temporal and lateral prefrontal cortex). Dorsal system learning is implicit and associates noncategorized stimuli within dimensional modules. Ventral system learning can be implicit or explicit It also allows associating events across dimensions and therefore is the basis of cross-task integration or interference, depending on degree of cross-task correlation of signals. Accordingly, lack of correlation rather than limited capacity is responsible for dual-task effects on learning. The theory is relevant to issues of attentional effects on learning; the representational basis of complex, sequential skills; hippocampal-versus basal ganglia-based learning; procedural versus declarative memory; and implicit versus explicit memory.     

Differential effects of cue changes and task changes on task-set selection costs

A task-switching paradigm with a 2:1 mapping between cues and tasks was used to separate cue-switching processes (indexed through pure cue-switch costs) from actual task-switching processes (indexed through additional costs in case of cue and task changes). A large portion of total switch costs was due to cue changes (Experiments 1 and 2), and cue-switch costs but not task-switch costs were sensitive to effects of practice (Experiment 1) and preparation (Experiment 2). In contrast, task-switch costs were particularly sensitive to response-priming effects (Experiments 1 and 2) and task-set inhibition (Experiment 3). Results suggest two processing stages relevant during task-set selection: cue-driven retrieval of task rules from long-term memory and the automatic application of rules to a particular stimulus situation.     

Predicting stuttering from linguistic factors for German speakers in two age groups

Brown's factors [J. Speech Disorders 10 (1945) 181] predict the likely loci of disfluency in English-speaking adults who stutter. A word is more likely to be stuttered for these speakers if it is a content word, starts with a consonant, is positioned at the beginning of a sentence, and if it is a long word. These same factors were examined in native German-speaking children and adults who stutter. Speech data of 15 German adults and 17 children were coded according to Brown's factors. For the adult group, it was predicted that words starting with consonants would not lead to as much of an increase in disfluencies compared with English samples, because of cross-linguistic differences in syllable onset properties. It was predicted that stuttering would be more likely in later sentence positions in German because in German the verb is usually near the end of a sentence. There were no obvious reasons to expect differences on the two remaining factors, content words and word length. With children, it was hypothesised that Brown's factors that specify level of linguistic difficulty would not be such a good predictor of stuttering rate. Specifically, it was predicted that the difference in stuttering rate between function and content words would be lower in children. For the adults both word type (content/function) and word length increased stuttering rate significantly, whereas changes in stuttering rate for the other two factors were non-significant. It was also found that when word difficulty (based on a combined measure of all factors) increased, stuttering rate rose. With children, only the word-length factor was significant, and stuttering rate was not governed to the same extent by overall word difficulty. Conclusions are drawn as to the effect of linguistic and motor influences on stuttering. EDUCATIONAL OBJECTIVES: The reader will learn about and be able to describe: (1) how linguistic factors affect stuttering rates in German; (2) the different patterns of adults and children who stutter and how language might influence this pattern; and (3) how to interpret these findings in light of a current theory of fluency failure.     

Psychophysiological outcome of cognitive, behavioral and psychophysiologically-based treatments of agoraphobia

Psychophysiological process and outcome phenomena were analyzed to examine differential temporal patterns within and across cognitive, behavioral and physiologically-based treatments of agoraphobia. Eighty-eight severe and chronic agoraphobics with panic attacks (DSM-III) were randomly assigned to one of three treatments: Paradoxical Intention, Graduated Exposure or Progressive Deep Muscle Relaxation Training. Protocol therapists, whose treatment integrity was objectively monitored, conducted 12 two-hour weekly sessions. All subjects received programmed practice instructions concurrent with their primary treatment. Analyses revealed numerous significant reductions on in vivo psychophysiological measures for the relaxation condition, a few improvements for the exposure treatment and no effects for the paradoxical intention modality. The mediating role of pretreatment physiological reactivity in treatment outcome and follow-up status was examined and revealed no significant associations. Synchrony-desynchrony patterns were found to vary widely according to both treatment phase and the time interval between assessments. No between-group differences were observed on the proportion of synchronizers. However, synchronizers exhibited superior outcome and follow-up compared to desynchronizers on all domains except the physiological measures. Conceptual, methodological and clinical implications of these findings are discussed with recommendations for future research.     

Ursachen der gegenseitigen Verdeckung von taktil dargebotenen Buchstaben: Unterbrechung,Summation oder Verzögerung?

Zusammenfassung Für die Erklärung der Verdeckung von Reizen in verschiedenen Sinnesmodalitäten mit einfacher Struktur wurden in der Literature bisher im wesentlichen zwei verschiedene Erklärungskonzepte diskutiert: Die Summationshypotheses behauptet, daß die Eindrücke von schnell aufeinanderfolgenden Reizen sich zu einer Gesamtrepräsentation überlagern, aus der die Einzelreize erschwert herauszuanalysieren sind, die Unterbrechungshypothese dagegen nimmt an, daß die Verdeckung auf eine Störung der Verarbeitung des einen Reizes durch die kurzzeitig folgende Darbietung eines weiteren Reizes zurückgeht. Zur Erklärung der gegenseitigen Verdeckung von taktil dargebotenen Buchstaben sind beide Hypothesen ungeeignet, weil sie die unterschiedliche Beeinträchtigung von Form- und Positionserkennung der Buchstaben nicht erfassen können. Deshalb wurde eine neue Hypothese aufgestellt: Die Repräsentation eines Reizes im sensorischen Register wird durch die Merkmalsanalyse des vorangegangenen Reizes kaum behindert, aber dessen Übertragung aus dem analysierenden System in das Kurzzeitgedächtnis eine bestimmte Zeit verzögert. Diese Verzögerungshypothese wurde mit einem Experiment überprüft, in dem 3 Vpn je etwa 12 Versuchsstunden lang die Erkennung von Buchstabenpaaren übten. Da die Diskrimination zwischen den Buchstaben bei taktiler Darbietung sehr viel schwieriger als bei visueller ist, wurden nur 5 Buchstaben im Experiment verwendet. Die Ergebnisse des Experiments werden durch ein mathematisches Modell beschrieben. Bezüglich der numerischen Werte der freien Parameter machen die 3 Hypothesen unterschiedliche Vorhersagen. Die Parameterschätzung ergab eine gute Übereinstimmung des Modells mit den Daten und zeigte eine Überlegenheit des Konzeptes Verzögerung für die Erklärung der gegenseitigen Verdeckung taktil dargebotener Buchstaben.

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Sources of mutual masking of tactile presented letters: Interruption, summation or delay?

Summary Two different explanations of the masking phenomenon with simple structured stimuli have been discussed in the literature: The summation hypothesis and the interruption hypothesis. The summation hypothesis maintains that the images of quickly succeeding stimuli superimpose and build up one unified representation from which the single stimuli are difficult to analyse. In contrast the interruption hypothesis assumes that masking is caused by the successive stimulus disturbing the processing of its predecessor. Both hypotheses are unacceptable for an explanation of the mutual masking of tactile presented letters where a different impairment of form and position recognition is observed. Therefore a third hypothesis was tried: The processing of a preceding stimulus hardly affects the representation of the successive one in the sensory register. Rather the transfer from the analysing system to short-term memory is delayed by a certain time. This delay hypothesis was tested by an experiment in which three subjects practiced to recognize pairs of letters for a total of 12 sessions. Since discrimination between letters is much more difficult with tactile compared to visual presentation only five letters were used as stimuli. The results are described by a mathematical model. The three hypotheses predict discrepant numerical values for the free parameters. Parameter estimation revealed a close fit between the general model and the data and showed a superiority of the delay hypothesis as an explanation of mutual masking of tactile presented stimuli.

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Für die wertvolle Beratung bei der Erstellung des endgültigen Textes danken wir besonders Herrn Professor Dr. K. F. Wender und Herr Dr. K. Nippert.     

Reliability and plasticity of response inhibition and interference control

This study investigated the internal reliability, temporal stability and plasticity of commonly used measures of inhibition-related functions. Stop-signal, go/no-go, antisaccade, Simon, Eriksen flanker, Stroop and Continuous Performance tasks were administered twice to 23 healthy participants over a period of approximately 11 weeks in order to assess test–retest correlations, internal consistency (Cronbach’s alpha), and systematic between as well as within session performance changes. Most of the inhibition-related measures showed good test–retest reliabilities and internal consistencies, with the exception of the stop-signal reaction time measure, which showed poor reliability. Generally no systematic performance changes were observed across the two assessments with the exception of four variables of the Eriksen flanker, Simon and Stroop task which showed reduced variability of reaction time and an improvement in the response time for incongruent trials at second assessment. Predominantly stable performance within one test session was shown for most measures. Overall, these results are informative for studies with designs requiring temporally stable parameters e.g. genetic or longitudinal treatment studies.     

Analytic thinking reduces belief in conspiracy theories

Belief in conspiracy theories has been associated with a range of negative health, civic, and social outcomes, requiring reliable methods of reducing such belief. Thinking dispositions have been highlighted as one possible factor associated with belief in conspiracy theories, but actual relationships have only been infrequently studied. In Study 1, we examined associations between belief in conspiracy theories and a range of measures of thinking dispositions in a British sample (N = 990). Results indicated that a stronger belief in conspiracy theories was significantly associated with lower analytic thinking and open-mindedness and greater intuitive thinking. In Studies 2–4, we examined the causational role played by analytic thinking in relation to conspiracist ideation. In Study 2 (N = 112), we showed that a verbal fluency task that elicited analytic thinking reduced belief in conspiracy theories. In Study 3 (N = 189), we found that an alternative method of eliciting analytic thinking, which related to cognitive disfluency, was effective at reducing conspiracist ideation in a student sample. In Study 4, we replicated the results of Study 3 among a general population sample (N = 140) in relation to generic conspiracist ideation and belief in conspiracy theories about the July 7, 2005, bombings in London. Our results highlight the potential utility of supporting attempts to promote analytic thinking as a means of countering the widespread acceptance of conspiracy theories.