Response force in RT tasks: Isolating effects of stimulus probability and response probability

Mattes, UIrich, and Miller (1997) found that as response probability decreases in a simple reaction time (RT) task, participants produce more forceful responses as well as longer RTs, suggesting a direct influence of preparatory processes on the motor system. In this previous study, however, response probability was confounded with stimulus probability, leaving open the possibility that response force was sensitive to stimulus- rather than response-related preparation. The present study was conducted to unravel the effects of stimulus and response probability. Experiment 1 manipulated stimulus probability and revealed that responses to a more probable stimulus are less forceful than responses to a less probable stimulus even when both stimuli require the same response. Experiment 2 demonstrated that this stimulus probability effect does not depend on the overall level of response probability. Experiment 3 showed an analogous effect for response probability when stimulus probability is kept constant. The complete pattern of results suggests that both stimulus probability and response probability affect the forcefulness of a response. It is argued that response probability exerts adirect influence on the motor system, whereas stimulus probability influences the motor system indirectly via premotoric adjustments.     

Betula: A Prospective Cohort Study on Memory,Health and Aging

This article describes the Betula Study with respect to objectives, design, participants, and assessment instruments for health and cognition. Three waves of data collection have been completed in 5-year intervals since 1988–1990. A fourth wave started in 2003 and will be completed in 2005. An overview of Betula research is presented under the headings of memory and cognition and cognitive neuroscience. Health-related issues and sex differences as well as comparisons between cross-sectional and longitudinal studies are discussed in the first section. The influence of different genes and of some brain abnormalities for memory functioning in adulthood and old age constitute main topics in the second section. New data are presented on the association between blood pressure and dementia. We demonstrated that a demented group of participants had higher levels of systolic blood pressure and pulse pressure than non-dementia controls 10 years before diagnosis. The new fourth wave of data collection will, in addition to enriching the Betula database, permit revisiting and reanalyzing the existing data from new perspectives.     

Deletion of the GluA1 AMPA receptor subunit alters the expression of short-term memory

Deletion of the GluA1 AMPA receptor subunit selectively impairs short-term memory for spatial locations. We further investigated this deficit by examining memory for discrete nonspatial visual stimuli in an operant chamber. Unconditioned suppression of magazine responding to visual stimuli was measured in wild-type and GluA1 knockout mice. Wild-type mice showed less suppression to a stimulus that had been presented recently than to a stimulus that had not. GluA1 knockout mice, however, showed greater suppression to a recent stimulus than to a nonrecent stimulus. Thus, GluA1 is not necessary for encoding, but affects the way that short-term memory is expressed.     

Nachsorge nach station?rer Psychotherapie f��r Essst?rungen

Background

Despite high relapse rates there is a lack of feasible, effective and efficient interventions to provide aftercare support to patients who complete treatment for an eating disorder. A program based on the short message service (SMS) and text messaging has been developed in order to provide such additional support to patients who undergo inpatient treatment for an eating disorder.

Materials and methods

A total of 165 patients with bulimia nervosa or an eating disorder not otherwise specified were randomly assigned either to the intervention group (n?=?82) with access to the text messaging intervention for 4 months following discharge from hospital or to the control group (n?=?83). The efficacy of the intervention was determined via the three eating disorder related subscales of the Eating Disorder Inventory (EDI-2) at 4 and 8 months follow-up and via the frequency of self-reported binge eating and compensatory behaviors (vomiting and abuse of laxatives) in the Short Evaluation of Eating Disorders (SEED) at 8 months follow-up.

Results

Participants in the intervention group reported significantly lower impairment on the EDI scales drive for thinness and body dissatisfaction both at 4 and 8 months follow-up. They also reported significantly fewer episodes of binge eating and vomiting. No differences were found for the EDI subscale bulimia and for the frequency of the use of laxatives.

Conclusion

The intervention based on text messaging proved efficacious in the aftercare treatment of patients with eating disorders. Chances and limitations concerning its use in the clinical routine as part of a stepped care model are discussed.     

Leaning to the left makes the Eiffel Tower seem smaller: posture-modulated estimation

In two experiments, we investigated whether body posture influences people's estimation of quantities. According to the mental-number-line theory, people mentally represent numbers along a line with smaller numbers on the left and larger numbers on the right. We hypothesized that surreptitiously making people lean to the right or to the left would affect their quantitative estimates. Participants answered estimation questions while standing on a Wii Balance Board. Posture was manipulated within subjects so that participants answered some questions while they leaned slightly to the left, some questions while they leaned slightly to the right, and some questions while they stood upright. Crucially, participants were not aware of this manipulation. Estimates were significantly smaller when participants leaned to the left than when they leaned to the right.     

The influence of dichotical fusion on the redundant signals effect,localization performance,and the mismatch negativity

In two experiments, each including a simple reaction time (RT) task, a localization task, and a passive oddball paradigm, the physical similarity between two dichotically presented auditory stimuli was manipulated. In both experiments, a redundant signals effect (RSE), high localization performance, and a reliable mismatch negativity (MMN) was observed for largely differing stimuli, suggesting that these are coded separately in auditory memory. In contrast, no RSE and a localization rate close to chance level (experiment 1) or at chance (experiment 2) were observed for stimuli differing to a lesser degree. Crucially, for such stimuli a small (experiment 1) or no (experiment 2) MMN were observed. These MMN results indicate that such stimuli tend to fuse into a single percept and that this fusion occurs rather early within information processing.     

Elaborative rehearsal of nontemporal information interferes with temporal processing of durations in the range of seconds but not milliseconds

The distinct timing hypothesis suggests a sensory mechanism for processing of durations in the range of milliseconds and a cognitively controlled mechanism for processing of longer durations. To test this hypothesis, we employed a dual-task approach to investigate the effects of maintenance and elaborative rehearsal on temporal processing of brief and long durations. Unlike mere maintenance rehearsal, elaborative rehearsal as a secondary task involved transfer of information from working to long-term memory and elaboration of information to enhance storage in long-term memory. Duration discrimination of brief intervals was not affected by a secondary cognitive task that required either maintenance or elaborative rehearsal. Concurrent elaborative rehearsal, however, impaired discrimination of longer durations as compared to maintenance rehearsal and a control condition with no secondary task. These findings endorse the distinct timing hypothesis and are in line with the notion that executive functions, such as continuous memory updating and active transfer of information into long-term memory interfere with temporal processing of durations in the second, but not in the millisecond range.     

A psychometric study of the Drug Use Disorders Identification Test-Extended in a Norwegian sample

Motivation is a widely used concept in substance use treatment, and is commonly seen as a premise for change during treatment. Different measures of motivation have been suggested. A relatively new instrument is the Drug Use Disorders Identification Test-Extended (DUDIT-E), developed in Sweden. This instrument has recently been introduced in Norway. The present study examined the Motivational Index of the Norwegian version of the Drug Use Disorders Identification Test-Extended (DUDIT-E). We tested whether the three-factor model ("Positive aspects of substance abuse"; "Negative aspects of substance abuse"; and "Treatment readiness") suggested by previous studies could be replicated in a sample of Norwegian inpatients. Responses to the DUDIT-E were obtained from 105 patients admitted to inpatient substance abuse treatment in Northern Norway. Exploratory common factor analyses were used to compare the factor structure from the current sample with the Swedish sample of mainly detoxification patients and prison inmates. The current sample did not include prison inmates, and it consisted of more women than the Swedish sample. The samples did not differ according to age or substance dependency. The analyses suggested that six primary factors was the most efficient way of combining the item scores, and not 11 as in the Swedish sample. A second-order factor analysis found best support for a two-factor solution, and hence, did not replicate the previously suggested three-factor model either. Several regression analyses comparing the efficiency of the different ways of combining the DUDIT scores in primary or secondary factor scores indicated that the model involving six sum scores had best merit and should be explored further.     

Human Embryos and Human Dignity: Differing Presuppositions in Human Embryo Research in Germany and Great Britain*

This article notes differences in legislation in Germany and Great Britain regarding human embryo research and looks for an explanation in their divergent intellectual traditions. Whereas the German Stem Cell Act invokes an anthropological concept of human dignity to ground its ban on using embryos for research, there is no definition of what it means to be human in either the British Human Fertilisation and Embryology Act or in the advisory Warnock‐Report. After studying the differences and providing some philosophical background, the essay distinguishes two notions that are significant for understanding human dignity. It then proposes from a theological point of view a basic understanding within a relational anthropology, and comes to the conclusion that because of continuity in development and their relational constitution, humans embryos should be accepted as human from the moment of conception.