The fast and the slow of skilled bimanual rhythm production: parallel versus integrated timing

Professional pianists performed 2 bimanual rhythms at a wide range of different tempos. The polyrhythmic task required the combination of 2 isochronous sequences (3 against 4) between the hands; in the syncopated rhythm task successive keystrokes formed intervals of identical (isochronous) durations. At slower tempos, pianists relied on integrated timing control merging successive intervals between the hands into a common reference frame. A timer-motor model is proposed based on the concepts of rate fluctuation and the distinction between target specification and timekeeper execution processes as a quantitative account of performance at slow tempos. At rapid rates expert pianists used hand-independent, parallel timing control. In alternative to a model based on a single central clock, findings support a model of flexible control structures with multiple timekeepers that can work in parallel to accommodate specific task constraints.     

The effects of expertise and age on rhythm production: adaptations to timing and sequencing constraints.

We investigate age- and expertise-related individual differences in component processes of rhythmic timing. To this end we apply analysis of covariance structure and symbolic dynamics to time series obtained from performances of two bimanual rhythm tasks at different tempos. Results show similar effects for peripheral motor implementation and timekeeper execution in young and older amateur pianists. Older participants show specific problems with temporal sequencing processes (specification of different target intervals). Expert pianists show lower variability in both motor implementation and timekeeper execution and they accommodate to the sequencing demands of different tempos by selectively relying on integrated or parallel timing. We argue that the observed timing control characteristics reflect individuals' adaptations to internal processing limitations and performance constraints.     

Basic forms of cognitive plasticity extended into the oldest-old: retest learning, age, and cognitive functioning

To address the question of whether cognitive plasticity varies by age and level of cognitive functioning in the older population, the authors used a self-guided retest paradigm to assess the basic forms of plasticity of 34 young-olds (M=74.4 years, range=70-79) and 34 oldest-olds (M=84.0 years, range=80-91), with half in each age group screened for high or low (midrange) level of cognitive functioning. As a whole, members of the sample represent about the upper two thirds of their age cohorts. Results show persistent, though age-reduced, learning in all samples and across all tests. However, age is not differentially "kinder" to the more able with respect to the age-graded decline in learning.     

Timing, sequencing, and executive control in repetitive movement production

The authors demonstrate that the timing and sequencing of target durations require low-level timing and executive control. Sixteen young (M-sub(age) = 19 years) and 16 older (M-sub(age) = 70 years) adults participated in 2 experiments. In Experiment 1, individual mean-variance functions for low-level timing (isochronous tapping) and the sequencing of multiple targets (rhythm production) revealed (a) a dissociation of low-level timing and sequencing in both age groups, (b) negligible age differences for low-level timing, and (c) large age differences for sequencing. Experiment 2 supported the distinction between low-level timing and executive functions: Selection against a dominant rhythm and switching between rhythms impaired performances in both age groups and induced pronounced perseveration of the dominant pattern in older adults.     

Age-specific problems in rhythmic timing

The authors investigated performance in 2 rhythm tasks in young (M = 23.8 years) and older (M = 71.4 years) amateur pianists to test whether slowing of a central clock can explain age-related changes in timing variability. Successive keystrokes in the rhythm tasks were separated by either identical (isochronous) time intervals or varying (anisochronous) intervals. Variability was comparable for young and older adults in the isochronous task; pronounced age effects were found for the anisochronous rhythm. Analyses of covariances between intervals rule out slowing of a central clock as an explanation of the findings, which instead support the distinction between target specification, timekeeper execution, and motor implementation proposed by the rhythm program hypothesis (D. Vorberg & A. M. Wing, 1996). Age stability was found at the level of motor implementation, but there were age-related deficits for processes related to target-duration specification.     

Die Therapeutenrotation

For seven years, the so-called “rotation of therapists”, has been a central part of OLITA, the outpatient longterm intensive therapy for alcoholics. Thus far, the participation of several equally responsible therapists in the treatment of a patient has rarely been seen as a defined therapeutic approach. The present work discusses whether the “rotation of therapists” has any essential influence on the success of OLITA. It considers both, potential advantages and disadvantages for patients and therapists and tries to identify conditions under which this approach appears to promote therapeutic interactions. Following an overview of the present knowledge regarding the therapeutic interaction in addiction therapy, a method is described which may be seen as the precedent of the “rotation of therapists”, the multiple psychotherapy. Finally, the practical procedure in OLITA is outlined as well as its theoretical background. New areas of application for the “rotation of therapists” are discussed.     

The role of intuition and deliberative thinking in experts' superior tactical decision-making

Current theories argue that human decision making is largely based on quick, automatic, and intuitive processes that are occasionally supplemented by slow controlled deliberation. Researchers, therefore, predominantly studied the heuristics of the automatic system in everyday decision making. Our study examines the role of slow deliberation for experts who exhibit superior decision-making outcomes in tactical chess problems with clear best moves. Our study uses advanced computer software to measure the objective value of actions preferred at the start versus the conclusion of decision making. It finds that both experts and less skilled individuals benefit significantly from extra deliberation regardless of whether the problem is easy or difficult. Our findings have important implications for the role of training for increasing decision making accuracy in many domains of expertise.     

The costs of taking it slowly: fast and slow movement timing in older age

We investigated adult age-differences in timing control of fast vs. slow repetitive movements using a dual-task approach. Twenty-two young (M = 24.23 yr) and 22 older adults (M = 66.64 yr) performed three cognitive tasks differing in working memory load and response production demands and they tapped series of 550-ms or 2100-ms target intervals. Single-task timing was comparable in both groups. Dual-task timing was characterized by shortening of produced intervals and increases in drift and variability. Dual-task costs for both cognitive and timing performances were pronounced at slower tapping tempos, an effect exacerbated in older adults. Our findings implicate attention and working memory processes as critical components of slow movement timing and sources of specific challenges thereof for older adults.     

Synchronizing movements with the metronome: nonlinear error correction and unstable periodic orbits.

The control of human hand movements is investigated in a simple synchronization task. We propose and analyze a stochastic model based on nonlinear error correction; a mechanism which implies the existence of unstable periodic orbits. This prediction is tested in an experiment with human subjects. We find that our experimental data are in good agreement with numerical simulations of our theoretical model. These results suggest that feedback control of the human motor systems shows nonlinear behavior.