No evidence for qualitative differences in the processing of short and long temporal intervals

Several lines of research suggest that two distinct timing mechanisms are involved in temporal information processing: a sensory mechanism for processing of durations in the range of milliseconds and a cognitively controlled mechanism for processing of longer durations. The present study employed a dual-task approach and a sensory interference paradigm to further elucidate the distinct timing hypothesis. Experiment 1 used mental arithmetic as a nontemporal secondary task, Experiment 2 a memory search task, and Experiment 3 a visuospatial memory task. In Experiment 4, a loudness manipulation was applied. Mental arithmetic and loudness manipulation affected temporal discrimination of both brief and long intervals, whereas the two remaining tasks did not influence timing performance. Observed differences in interference patterns may be explained by some tasks being more difficult than others. The overall pattern of results argues against two qualitatively distinct timing mechanisms, but is consistent with attention-based cognitive models of human timing.     

On the role of verbalization during task set selection: Switching or serial order control?

Recent task-switching work in which paper-and-pencil administered single-task lists were compared with task-alternation lists has demonstrated large increases in task-switch costs with concurrent articulatory suppression (AS), implicating a crucial role for verbalization during switching (Baddeley, Chincotta, & Adlam, 2001; Emerson & Miyake, 2003). Experiment 1 replicated this result, using computerized assessment, albeit with much smaller effect sizes than in the original reports. In Experiment 2, AS interference was reduced when a sequential cue (spatial location) that indicated the current position in the sequence of task alternations was given. Finally, in Experiment 3, switch trials and no-switch trials were compared within a block of alternating runs of two tasks. Again, AS interference was obtained mainly when the endogenous sequencing demand was high, and it was comparable for no-switch and switch trials. These results suggest that verbalization may be critical for endogenous maintenance and updating of a sequential plan, rather than exclusively for the actual switching process.     

Intentions determine the effect of invisible metacontrast-masked primes: evidence for top-down contingencies in a peripheral cuing task

In 5 experiments, the authors tested whether the processing of nonconscious spatial stimulus information depends on a prior intention. This test was conducted with the metacontrast dissociation paradigm. Experiment 1 demonstrated that masked primes that could not be discriminated above chance level affected responses to the visible stimuli that masked them. Experiments 2 and 3 showed that this effect was abolished when the task instruction was changed in such a way that the primes ceased to be task relevant. Experiments 4 and 5 demonstrated that a prime's effect depended on whether it was associated with the same response as the target or with an opposite response.     

Conflict, consciousness, and control

To what degree is executive conflict resolution dependent on conflict awareness? A recent study by Dehaene et al. compared neural responses to conflict elicited through either visible or subliminal primes. Despite behavioral conflict effects for both prime types, neural activity in a control network including the anterior cingulate cortex (ACC) was present only for visible primes. Along with other recent results, these findings have important implications for theories on the relationship between ACC, consciousness, and cognitive control.     

Genetic Cancer Risk Assessment and Counseling: Recommendations of the National Society of Genetic Counselors

These cancer genetic counseling recommendations describe the medical, psychosocial, and ethical ramifications of identifying at-risk individuals through cancer risk assessment with or without genetic testing. They were developed by members of the Practice Issues Subcommittee of the National Society of Genetic Counselors Cancer Genetic Counseling Special Interest Group. The information contained in this document is derived from extensive review of the current literature on cancer genetic risk assessment and counseling as well as the personal expertise of genetic counselors specializing in cancer genetics. The recommendations are intended to provide information about the process of genetic counseling and risk assessment for hereditary cancer disorders rather than specific information about individual syndromes. Key components include the intake (medical and family histories), psychosocial assessment (assessment of risk perception), cancer risk assessment (determination and communication of risk), molecular testing for hereditary cancer syndromes (regulations, informed consent, and counseling process), and follow-up considerations. These recommendations should not be construed as dictating an exclusive course of management, nor does use of such recommendations guarantee a particular outcome. These recommendations do not displace a health care provider's professional judgment based on the clinical circumstances of a client.     

Government initiatives in autism clinical trials

Randomized clinical trials remain the most valid method of testing the efficacy and safety of treatments. While efforts to elucidate the genetic and neurodevelopmental bases of autism are underway, clinicians and families are in need of scientifically valid information on how to best treat patients with autism. The effectiveness of many interventions currently used in communities has not been adequately tested. Given the high public health relevance of autism treatment research and the low interest of the pharmaceutical industry in autism, the role of the National Institutes of Health in supporting this research is paramount. Among recently launched initiatives in autism clinical trials, there are the Research Units on Pediatric Psychopharmacology Autism Network and the network of centers for Studies to Advance Autism Research and Treatment. These and other government activities in the area of autism clinical trials are here briefly reviewed.     

Awareness in memory: being explicit about the role of sleep

Sleep is crucial to the 'off-line' consolidation of procedural memory. A recent study by Robertson et al. shows that this might hold true only if the task is trained explicitly, that is, with the subject being aware of the task structure. These new data add to emerging evidence that sleep-related memory consolidation involves an interaction between different memory systems.     

Peripheral cuing by abrupt-onset cues: the influence of color in S-R corresponding conditions

Research on visuospatial attention indicates that a peripheral abrupt-onset cue at target position (valid condition) facilitates processing of the target, whereas a cue at another position interferes. This validity effect seems to be contingent on a similarity of the cue's color to the set of target colors (cf. J. Exp. Psychol.: Human Percep. Perform. 18 (1992) 1030). In Experiments 1-3, we confirm this contingency with cues that have the potential to activate responses. Thus, attentional capture and response capture are apparently governed by the same principle. In Experiment 2, it is demonstrated that color priming is not responsible for the contingency. In Experiment 3, it is shown that a more efficient reallocation of attention after color-dissimilar cues than after color-similar cues might contribute to the contingency.     

Threshold estimation in two-alternative forced-choice (2AFC) tasks: the Spearman-Kärber method

The Spearman-K?rber method can be used to estimate the threshold value or difference limen in two-alternative forced-choice tasks. This method yields a simple estimator for the difference limen and its standard error, so that both can be calculated with a pocket calculator. In contrast to previous estimators, the present approach does not require any assumptions about the shape of the true underlying psychometric function. The performance of this new nonparametric estimator is compared with the standard technique of probit analysis. The Spearman-K?rber method appears to be a valuable addition to the toolbox of psychophysical methods, because it is most accurate for estimating the mean (i.e., absolute and difference thresholds) and dispersion of the psychometric function, although it is not optimal for estimating percentile-based parameters of this function.     

Effects of redundant visual stimuli on temporal order judgments

Four experiments were conducted in order to compare the effects of stimulus redundancy on temporal order judgments (TOJs) and reaction times (RTs). In Experiments 1 and 2, participants were presented in each trial with a tone and either a single visual stimulus or two redundant visual stimuli. They were asked to judge whether the tone or the visual display was presented first. Judgments of the relative onset times of the visual and the auditory stimuli were virtually unaffected by the presentation of redundant, rather than single, visual stimuli. Experiments 3 and 4 used simple RT tasks with the same stimuli, and responses were much faster to redundant than to single visual stimuli. It appears that the traditional speedup of RT associated with redundant visual stimuli arises after the stimulus detection processes to which TOJs are sensitive.