LAB 1: MOTOR LEARNING & DEVELOPMENT REACTION TIME AND MEASUREMENT OF SKILLED PERFORMANCE Name: Score: Part I: Reaction Time Environments Introduction: Reaction time is a measure of how long it takes a performer to prepare and initiate an intended movement. Simply, how quickly the performer can initiate a required action. It is considered by some as the measure of your decision time because it does not include any movement but only the time it take for one to make a decision whether to move or not to move. Reaction time research has indicated that expert players make faster decisions than non-experts of a sport. Also, coaches and teachers who provide sport specific situational training or practices actually decreases (reaction time become quicker) the performer s time to make a decision when the situations arise in a contest and/or game. There are three types of reaction time situations or environments that exist in everyday life or in sport. They are simple, choice, and discrimination reaction time situations or environments. A simple reaction time environment is where the performer is involved in one signal and only one response movement, such as the start of the 100 meter sprint in track. A choice reaction time environment is where the performer is involved in a situation where there is more that one signal and each signal has a designated response movement, such as the hunter comes along a flock of ducks will shoot the mallard male duck but not the female. A discriminate reaction time environment is where the performer is involved in a situation where there is more than one signal but only performs a response movement to a specific signal, such as a walker must respond differently by walking over the log and around rocks on a path. Purpose: The purpose of this lab is to demonstrate how one s decision time (reaction time) can be influenced by the characteristics of different reaction time situations or environments. Equipment: 4 MoArt reaction timers. Procedure: Students of this lab will be divided into four groups. At the beginning of the data collection phase, the instructor will assign each group to a different reaction time environment. Each student will complete all three reaction time environments. Each student is to perform 10 trials at each of the reaction time environments. For every trial, you should focus your attention on the stimuli and not your response or movement in depressing the key. Each student should be an experimenter for at least one student in the group at each reaction time environment. The experimenter is responsible for recording their subject s reaction time in milliseconds (ms), for each trial. In the simple reaction time environment, the student will be positioned in front a reaction timer. For each trial a warning light will appear then after a random foreperiod (waiting period) a red light will appear. Once the red light appears the subject will as quickly as possible depress a button or key using their index finger of their non-dominate hand. 1
In the choice reaction time environment the student will be positioned in front a reaction timer and place their non-dominate hand near the display where five button, one for each finger with a corresponding light above each button, is located. For each trial a warning light will appear then after a random foreperiod a light above one of the five buttons will be lit. Once the light appears to be lit, the student will attempt to depress the button or key with the corresponding finger as quickly as possible. Keep the subject honest by randomizing when the designated stimuli will appear. In the discriminate reaction time environment the student will be positioned in front a reaction timer and place their non-dominate hand on the key near the display. For each trial a warning light will appear then after a random foreperiod a light or audible signal will occur. Once the light or sound appears, the student will attempt to depress the key as quickly as possible. Keep the subject honest by randomizing when the designated stimuli will appear. Make sure you indicate with a * those trials the subject responded to a sound stimulus. Data Collection: Each student s reaction time scores in ms will be recorded on the table below. Realize that ms will be displayed to three places, that is,.217. When you record your reaction time score drop the decimal place and record your score as 217. Once you have recorded the ten trials for each reaction environment, calculate your mean reaction time for the environment and record the mean in the space below the 15 th trial. The mean reaction times for each environment will be used later to graph your results and to answer the lab questions. Individual Data Trials Simple RT Choice RT Discriminate RT 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Mean Graphing: Develop a bar graph (called a column graph in excel) including the overall RT environmental means. Create a title that includes the independent and dependent variables, label the X & Y axis, include a legend, and the means on top of each bar. 2
Part II: Relationship between Reaction Time and Movement Time Introduction. When a performance approaches excellence if is often attributed to the fact the performance has good reaction time. In many sports activities the good reaction time of the participant seemingly is a major component of high skill levels. Reaction time is defined as the lapse in time between the presentation of the stimulus and the first sign of overt response, this usually being a muscular response. It should be noted that this definition does not include that component of skill this speed of the movement itself. Reaction time then is only a small part of the total time that any physical task requires for completion; and since it is determined by the response of neurophysiologic mechanisms, it is usually considered to be somewhat predetermined, set-in, or regulated more by genetic than environmental factors. Movement time, on the other hand, is that amount of time from the first overt sign of movement to the completion of the task. Speed of movement is highly specific varying from one part of the body another as well as in the direction of movement. Movement time is thought to vary with such factors as practice, strength, age, gender, joint mobility, and tissue consistency. Obviously both factors, i.e., reaction time and movement time, are important. Purpose. This experiment is designed to show the relationship between these two important components of skilled performance. As a result of this demonstration you should see whether or not a performer tends to be a fast reactor and a fast mover or if there seems to be no such predictable pattern. Task: 4 MoArt Timers Procedure. The subject is seated directly in front of a MoArt timer or reaction timer. The Subject will be pressing their index finger on a button. A randomized foreperiod between 1 and 4 second will be given before it actuates a light. Upon seeing the light, the subject will remove his or her finger from the button as quickly as possible and move his or her hand as fast as possible to press another button on the MoArt board. Fifteen trials are given. Results: Record the reaction time (X) and movement time (Y) on the data table. Use the below formula to calculate r (correlation) for these scores. Trial X Y X 2 Y 2 XY 1 2 3 4 5 6 7 8 9 10 3
X Y X 2 Y 2 XY= r = [N XY ( X) ( Y)] 2 / [N X 2 - ( X) 2 ] [N Y 2 - ( Y) 2 ] r = Graph: Develop a bar graph that includes your RT and MT overall means. Create a title, label the X & Y axis, and include means on top of each bar. Lab Questions: 1. Which environment (simpler, choice or discriminate) produced the fastest reaction times? Slowest? Do explain using your data and analysis? What do you account for the differences in reaction times between environments? 2. What do you think would have happened to your reaction times in the simple reaction time environment if instead of varying the fore period (waiting period) was kept constant for every trial? 3. Did vision or sound stimuli produce faster discriminate decision times? Why was one sense faster? Describe a simple situation where this might be important? 4. Identify one example for simple, choice, and discriminate environment that exist in a real life situation. These examples cannot come from your text. 5. Report your r or correlation value. What was the relationship between reaction time and movement time? 6. Describe a simple test you might utilize to help you decide which members of your track team should be sprinters or distance runners? Correlation Example. Significant information is gained when a relationship between measures is discovered. This necessitates having at least two measures for the same individual. Correlations are described in terms of a number, thus again providing much information in a very compact form. If a perfect positive relationship exists between 2 variables then the correlation coefficient (r) is +1.00. If no relationship exist it is 0.00. If the variables are totally independent of or in perfect disagreement with one another, then inverse relationship exists and the r = -1.00. The basic formula of r is: r = [N XY ( X) ( Y)] 2 / [N X 2 - ( X) 2 ] [N Y 2 - ( Y) 2 ] All you need is a pocket calculator. If you have Statistic Toolpac in excel, you can easily calculate it with your computer or use other statistical packages such as SAS or SPSS. Here is an example: 4
Trial X Y X 2 Y 2 XY 1 10 4 100 16 40 2 12 8 144 64 96 3 15 10 225 100 150 4 21 15 441 225 315 5 8 6 64 36 48 6 3 1 9 1 3 7 14 6 196 36 84 8 16 12 256 144 192 9 18 10 324 100 180 10 8 4 64 16 32 X= 125 Y=76 X 2 =1823 Y 2 =738 XY=1140 r = [N XY ( X) ( Y)] 2 / [N X 2 - ( X) 2 ] [N Y 2 - ( Y) 2 ] r = [10(110) (125) (76)] 2 / [10(1823) - (125) 2 ] [10(738) - (76) 2 ] = (11400 9500) 2 / (18230 15625) (7380 5776) = 1900 2 / (2605) (1604) = 3610,000/4178,420 =.86 =.93 Since the correlation coefficient is perhaps one of the most valuable of all statistical tools yet at the same time is a most widely misused statistic. First of all a correlation coefficient regardless of its magnitude does not necessarily indicate a causal relationship. Even though a high r is found between X and Y, for example, it may not correctly inferred from this that X causes Y; the relationship between X and Y is merely stated by the correlation coefficient. An example of such an incorrect interpretation of r is this: thin girls where small size dresses; therefore if one wears a small size dress this will cause one to be thin! Another point that should be noted is that the correlation coefficient does not represent a percentage of relationship. An r of.40 does not mean 40% agreement. Neither does an r of.40 imply twice the relationship of an r of.20 nor does an increase in r from.50 to.70 have the same meaning as an increase from.60 to.80. A correlation coefficient is just an index number. If the coefficient is squared the resulting words if r =.50 between X and Y then.25 or 25% of the variance due to chance is accounted for, but note that 75% of the time such a relationship between X and Y would be found by chance. A correlation must be high to be of significant predictive value but even modest correlations may reveal relationships of much importance. How high an r must be depends upon what we expect to do with it. Coefficients are interpreted in comparison with their standard errors. They are not absolute and they refer to the specific circumstances under which they were obtained; all statistics must be interpreted in terms of probable sampling errors. A rough interpretation of r is: Between 0 and.20 little or very little relationship Between.21 and.40 low relationship 5
Between.41 and.60 some relationship but weak Between.61 and.80 high relationship Between.81 and 1.00 - extremely high relationship 6