Three experiments compared learning of relative and absolute timing of a sequential key-pressing task by physical and observational practice. Experiment 1 compared a task with a complex internal structure (goal proportions of 22.2, 44.4, 33.4 on the three movement segments) to one with a simpler structure (goal proportions of 33.3, 33.3, 33.4). Observers only learned the relative timing as well as physical practicers when the internal structure was simple, but learned the absolute timing in both conditions. Experiment 2 compared variable (700, 900, and 1100 ms overall time) with constant practice (900 ms overall time). Observers of constant practice models learned the relative timing better than no-practice control participants, but not as well as the models, while observers of variable practice models learned the relative timing no better than the control group. Observers in both practice conditions were able to produce the absolute timing as well as those who physically practiced. In Experiment 3 observers of an expert model were able to produce the relative timing as well as those who physically practiced the skill, while those who observed learning models were not. All observers and the physical practice participants were able to produce the overall duration as well as the expert model. The results of these three experiments support earlier findings that increasing stability during practice promotes better learning of relative timing, but that absolute timing can be learned under less-stable conditions (Lai, Shea, Wulf, & Wright, 2000b). These findings also have important implications on the limitations of Scully and Newells' (1985) prediction that relative timing, but not absolute timing, could be learned by observation. Experiments 1-3 along with earlier findings (Black & Wright, 2000) have consistently found that absolute timing could be learned by observers even as the nature of the task, practice schedule, and model are manipulated. Furthermore, the results suggest a limitation to the effectiveness of learning models (Adams, 1986; McCullagh & Caird, 1990).

The ability of spatial transfer to occur in movement sequences is reflected upon in theoretical perspectives, but limited research has been done to verify to what extent spatial characteristics of a sequential learning task occur. Three experiments were designed to determine participants’ ability to transfer a learned movement sequence to new spatial locations. A 16-element dynamic arm movement sequence was used in all experiments. The task required participants to move a horizontal lever to sequentially projected targets. Experiment 1 included 2 groups. One group practiced a pattern in which targets were located at 20, 40, 60, and 80° from the start position. The other group practiced a pattern with targets at 20, 26.67, 60, and 80°. The results indicated that participants could effectively transfer to new target configurations regardless of whether they required proportional or non-proportional spatial changes to the movement pattern. Experiment 2 assessed the effects of extended practice on proportional and non-proportional spatial transfer. The data indicated that while participants can effectively transfer to both proportional and non-proportional spatial transfer conditions after one day of practice, they are only effective at transferring to proportional transfer conditions after 4 days of practice. The results are discussed in terms of the mechanism by which response sequences become increasingly specific over extended practice in an attempt to optimize movement production. Just as response sequences became more fluent and thus more specific with extended practice in Experiment 2, Experiment 3 tested whether this stage of specificity may occur sooner in an easier task than in a more difficult task. The 2 groups in Experiment 3 included a less difficult sequential pattern practiced over either 1 or 4 days. The results support the existence of practice improvement limitations based upon simplicity versus complexity of the task.

Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 94-99).

published_or_final_version / Sports Science / Master / Master of Science in Sports Science

published_or_final_version / Psychology / Master / Master of Philosophy

Not available / text

Not available / text

Many species-specific sensorimotor behaviors, such as speech in humans, emerge from the interplay between genetically defined developmental programs and sensory experience. How these processes interact during learning to shape motor circuits is not well understood. The zebra finch (Taeniopygia guttata), an oscine bird that learns to imitate the song of its tutor (usually the father), provides a uniquely tractable model for exploring this question. Song learning in zebra finches takes place during a discrete three-month period during which male juveniles progress from producing highly variable rudimentary sounds that are noisy and unstructured, to a highly stereotyped imitation of their tutor's song. Here I characterize learning-related changes in the functional connectivity within a motor cortex-analogue brain area (RA) that control song production.

Stroke is the leading cause of long-lasting disability in the United States and disproportionately affects adults in later life. Age-related decreases in dexterity and neural plasticity may contribute to the poorer prognosis of older stroke survivors, even following rehabilitative physical therapy. The goal of these dissertation studies is to determine how the cortical plasticity underlying motor skill learning, both before and after brain injury, changes in the aged brain. The general hypothesis of these studies is that age-related changes in motor performance and the limited ability to regain function following brain injury are associated with dysfunctional plasticity of the forelimb representation in the motor cortex. This hypothesis was tested in intact C57BL/6 mice by training them on a skilled reaching task and deriving intracortical microstimulation evoked motor cortical representations of the forelimb to determine training-induced changes in the function of the motor cortex. After ischemic lesions, age-dependencies in the effects of rehabilitative training in skilled reaching on forelimb motor cortical representations were investigated. Prior to injury, intact young and aged mice learned a skilled reaching task in similar time frames and with similar success rates. Training-induced reorganization in the young mouse motor cortex occurred in the caudal forelimb area, which is homologous to the primary motor cortex of primates. However, the rostral forelimb area, a potential premotor cortex, was larger in aged mice compared to young mice. Following focal ischemic lesions of the forelimb area of the sensorimotor cortex, aged mice had larger lesions and were more impaired than young mice, but both groups regained reaching ability after 9 weeks of rehabilitative training. Post-operative training resulted in plasticity of the rostral forelimb area in young mice, but we failed to see reorganization in the forelimb map of aged mice following rehabilitative training. These dissertation studies suggest that more severe brain damage in response to ischemia leads to poorer outcome in aged animals. Although the reorganization of motor cortex following initial skill learning and relearning following brain damage changes with age, the ability to learn motor tasks and improve function with rehabilitative training is maintained in healthy aging. / text

A size-weight illusion (SWI) occurs when a large object and small object of equal mass but different volume are lifted and the small object is perceived as heavier than the large object. All previous studies of the SWI used similar coloured objects and found that individuals initially use more force to lift the large object, compared to the small object but then use similar forces for the two objects on subsequent lifts. In contrast to the change in lifting forces over trials, the perceptual illusion stays consistent across all trials. The goal of the current study was to determine if introducing different colours for the SWI stimuli could alter participants’ expectations about the masses of the two objects and therefore modify the perceptual SWI. Participants lifted SWI stimuli that were either identical in colour or stimuli of different colour.