Task difficulty and frequency of knowledge of results in well young and elderly adults

While there is evidence of age-related changes in both cognition and motor control, little is known about the effect of age on learning a new motor task. The purpose of this study was to compare the skill acquisition, skill retention, and skill transfer of motor skills in younger and elderly adults on relatively easy and relatively difficult tasks across various frequencies of knowledge of results (KR). It was hypothesized that the transfer and retention of skills depend upon the task difficulty and frequency of KR, and that there will be differences in the performance between the two age groups. Participants included 66 younger adults, aged 20 to 35 years, and 20 older adults, aged 60 to 75 years. All participants were well and lived independently. The task involved turning a knob to control the size of a bar to match the movements of a target on a computer screen. Participants were randomly assigned to one of six conditions, including the 100% KR easy task, the 33% KR easy task, the 0% KR easy task, the 100% KR hard task, the 33% KR hard task, and the 0% KR hard task. Feedback provided at a constant rate for older adults and at a rate of once every three trials for younger adults while learning a relatively difficult task resulted in an enhanced ability to generalize to a novel but similar motor task. Future studies should include a larger sample size and include a narrower age span of younger and older participants. Task Difficulty and Frequency of KR 3 Task Difficulty and Frequency of Knowledge of Results in Well Young and Elderly Adults It is predicted that by the year 2030, there will be 71 million Americans over the age of 65 which will account for approximately 20% of the United States population. Two leading factors for this prediction include the aging baby boomers and longer life spans due to improved medical care and prevention (Centers for Disease Control & Prevention and The Merck Company Foundation, 2007). In addition to the growing elderly population, our society has become more dependent upon technology. Technology is used in every aspect of our instrumental occupations of daily living including banking, communication, meal preparation, recreation, and community mobility. The success of the older adult population utilizing these devices (cellular phones, DVD-R, e-mail, etc.) will largely depend on their ability to use effective learning strategies. Therefore, an improved understanding of how younger and older adults acquire, retain, and transfer motor skills is needed in order to facilitate occupations within the rehabilitation profession. Memory gives support to learning. Two types of memory that contribute to learning include procedural memory and declarative memory. Procedural memory involves information or skills that are automatically learned without conscious thought. This memory task is often thought to be strongly associated with motor skill learning. For example, the initial difficulty of driving a car in traffic becomes automatic with practice. Declarative memory is a type of memory that is consciously understood as being a previously learned fact or experienced event; it is information that can be verbalized (Tunney, Taylor, Higbie & Haist, 2002). Declarative memory may contribute to motor skill learning by allowing the individual to consciously repeat the task until it becomes automatic and does not require attention (Shumway-Cook & Woolacott, 1995). It has been well-documented that declarative memory declines with the aging process Task Difficulty and Frequency of KR 4 (Woodruff-Pak & Finkbiner, 1995; Nyberg et al., 1996; Lipinska & Backman, 1997). In a study by Vakil and Agmon-Ashkenazi (1997) it was found that a group of younger adults demonstrated a steeper learning rate than that of the older adults in declarative tasks. However, in procedural tasks the two groups did not differ in their rates of learning. The declarative tests employed were the Visual Paired Associates, a subtest of the Wechsler Memory Scale-Revised, and the Rey Auditory-Verbal Learning Test. The procedural task included the tower of Hanoi puzzle and Porteus mazes. There are many motor learning strategies that involve feedback. One of the more common types is known as knowledge of results (KR). This type of feedback is defined as being augmented and is facilitated when the learner receives an immediate evaluation of his or her motor performance. For example, if the goal was to roll a “strike” during a bowling frame, the knowledge of results would be the number of pins that were knocked down. There is also a degree of accuracy of information known as precision of KR (Schmidt & Lee, 2005). The qualitative degree would be feedback indicating “not a strike” or “strike. ” The quantitative degree would be feedback indicating “3 pins standing. ” The frequency of KR can influence the effectiveness of motor learning, such as after every trial (100% KR) or after every other trial (50% KR). There have been several studies indicating that learners performed better during the acquisition phase with 100% KR, but those that received 50% KR remembered the skill better (Lai & Shea, 1998; Schmidt, Young, Swinnen, & Shapiro, 1989; Winstein & Schmidt, 1990). Schmidt, Young, Swinnen, and Shapiro (1989) indicated that KR provides information about the response outcome causing the learner to generate a new response for the subsequent trial that is more accurate to the goal. However, if KR is utilized for every trial, learning becomes less effective due to the learner’s dependence on the feedback. If one relies on memory or cognitive Task Difficulty and Frequency of KR 5 effort as is the case with a reduced frequency of KR (e.g., 50% or 33%), the result will be an enhanced recall of the task. With a basic understanding of knowledge of results, it is important to now focus on a theoretical process of motor learning, known as the schema theory. All individuals possess categorical rules that are used to interpret the world. New information is processed according to how it fits into these rules, called schema. For instance, over time an individual will store visual stimuli in his or her memory that allow the individual to determine the proper form when shooting a free-throw in basketball. The base of this learning theory is the idea of a generalized motor program (GMP), which Schmidt defined as “a motor program whose expression can be varied depending on the choice of certain parameters” (2005, p. 464). According to the schema theory, after the GMP is selected and a movement is accomplished, there are four types of information stored in the short-term memory: (1) the initial conditions, (2) the response specifications for the motor program, (3) sensory consequences of the response produced, and (4) augmented feedback about the outcome of the movement (Schmidt, 1975: Schmidt & Lee, 2005). All four sources of information are interconnected by recall and recognition schemas. Recall schema is responsible for movement production and recognition schema is responsible for movement evaluation. Prior to the movement, the individual selects a movement outcome. Next, with recognition schema, the individual can estimate the sensory consequences that will occur if the movement is successfully produced; this is called expected sensory consequences. An interpretation of this theory is that an individual learns a skill by learning rules about the functioning of our bodies, such as what our muscles do, and how certain actions feel (Schmidt &