Ronald L. Knoll

6 – The Latency and Duration of Rapid Movement Sequences: Comparisons of Speech and Typewriting

Publisher Summary This chapter discusses the temporal patterns of rapid movement sequences in speech and typewriting and what these patterns might mean in relation to the advance planning or motor programming of such sequences. The chapter discusses response factors that affect the time to initiate a prespecified rapid movement sequence after a signal when the goal is to complete the sequence as quickly as possible as well as how such factors affect the rate at which movements in the sequence are produced. The response factor of central interest is number of elements in the sequence. The effect of the length of a movement sequence on its latency is based partly on the possibility that it reflects a latency component used for advance planning of the entire sequence: The length effect would then measure the extra time required to prepare extra elements. The idea that changes in reaction time might reflect changes in sequence preparation in this way proposed that simple reaction time increased with the number of elements in a sequence of movements made with one arm. A part of the reaction time includes the time to gain access to stored information concerning the whole sequence: a process akin to loading a program into a motor buffer, with sequences containing more elements requiring larger programs, and larger programs requiring more loading time.

Motor Programs and Hierarchical Organization in the Control of Rapid Speech

We provide a summary of our recent research on the control of rapid action sequences in speech production, emphasizing findings about the advance planning and hierarchical organization of such utteran

Perception, Production, and Imitation of Time Ratios by Skilled Musicians

We have described our exploration of the judgment, production, and imitation of fractions of a beat by skilled musicians, illustrating our findings with data from violinist and conductor Paul Zukofsky. For small fractions we found systematic and substantial errors. In the judgment task small stimulus fractions are associated with names that are too large (overestimation). In both production and imitation tasks the fractions produced were too large (overproduction, overimitation). A summary of our findings and of the expectations they violate is provided in Figure 7. The temporal patterns we used are perhaps the simplest that qualify as rhythms, incorporating just a beat interval and a fraction. The phenomena we discovered in relation to these simple patterns, and their implications for underlying mechanisms, must be considered in attempts to understand the perception and production of more complex rhythms, as in actual music. We explored and rejected several plausible explanations for the overestimation and overproduction of small fractions. Although we have as yet no satisfactory explanations of the errors themselves, relations among the errors have powerful implications for human timing mechanisms. The relation between the errors in judgment and production requires us to reject a feedback model of production, in which a subject uses the same processes as in the judgment task to evaluate and adjust his performance in the production task. An explanation of the inconsistency between judgment and production seems most likely to lie in a change in time perception induced by the production task. Together with the existence of systematic errors in judgment, the equality of the errors in production and imitation argues that imitation is not accomplished by concatenating all the processes used in judgment and production. Our results are instead consistent with a model containing four internal transformation processes, in which judgment and production share no process, but do involve the same internal-fraction representation, and in which imitation shares one process with judgment and another with production.

Subdivision of the beat: Estimation and production of time ratio by skilled musicians

Professional musicians served as subjects in experiments on time estimation and production. In one procedure, equally spaced high‐frequency clicks defined rhythmic beats. Intervening lower‐frequency marker clicks indicated a fraction of the interval between beats. Subjects estimated the fraction. In a second procedure, equally spaced clicks were presented without the intervening marker clicks. Subjects attempted to produce a specified fraction of the interval between beats by responding with a finger tap after each click. If produced fractions are adjusted by estimating the time between click occurrence and response feedback, then any biases in the two tasks should be equal in magnitude and opposite in direction. For large fractions, estimated and produced fractions were unbiased. However, for small fractions, both estimated and produced fractions were too large. With respect to a feedback theory of production, the common direction of the two biases is paradoxical. [Work partially supported by IRCAM and R...