Rhythms are fundamental to behavior, but the control mechanism for timed responses is not known. Many theorists have assumed that there is a central clock coordinating behavior in all sensory modalities and response modes. We tested this hypothesis using a rhythmic tapping task in which university undergraduates first attempted to synchronize responses with brief auditory, tactile, or visual stimuli and then continued to tap at the same rate on their own. Performance was most variable with visual stimuli and least variable with auditory stimuli. The detailed results suggest that performances are not based on a common clock, but, rather, different strategies are employed when the task is presented in different modalities. We reject the hypothesis of a single timing mechanism as controlling behavior and, in doing so, question the validity of information processing models that are formulated without regard to temporal relations among their conjectured processes.

Emerging public health standards, performance assessment tools, and accreditation models hold significant promise for defining and standardizing public health practice, yet the lack of empirical research on their relationship to outcomes represents a serious barrier to adoption. Given the growing interest and momentum related to public health agency assessment and accreditation efforts, there is increasing need for evidence that performance standards and associated accreditation programs are effective means for moving public health systems toward the ultimate goal of population and community health improvement. This article provides an overview of accreditation in health and other industries, and its relationship to outcomes. We examine lessons that might have meaningful public health translations, as well as influences in and on public health that pose challenges for research and evaluation in this area. Finally, we propose a logic model framework to help depict the ways in which we can begin to explore the impact accreditation has on various levels of outcomes. This logic model is intended to guide the development of measures and to serve as a tool to help convey the breadth and depth of research needed to link accreditation to health outcomes.