Visual & Auditory Skills Lab

Transcription

1 Visual & Auditory Skills Lab Name: Score: Introduction This lab consists of a series of experiments that explore various perceptual, vision, and balance skills that help us understand how we perform motor skill. The first activity involves examining the role vision plays in maintaining ones balance. The second activity is the effects of visual memory on walking ability. The third activity involves attending to a sensory and motor set when performing to an auditory stimlus, and fourth and final activity is accessing your visual acuity, contrast sensitivity, and depth perception. Visual Activity 1: Balance & Vision Purpose: The purpose of this activity is to determine the effects of vision on one s ability to balance. Procedures & Equipment: Researchers have studied balance by using a stabilometer. With stabilometer, the subject must balance on a platform suspended on a single axis across its midline. The subject places one foot one each side of this axis, similar to attempting to balance on the center of seesaw. While balancing, you will be asked to maintain your stance when performing with your eye s closed and eyes open. You will attempt to balance for 45 seconds. The number of seconds that you are in balance will be your score. You will be given to two attempts with eye s open or closed, randomly selected. Total time of the two attempts will be your score for visual condition. Trial 1 Trial 2 Total Time Visual Conditions Eyes Open Eyes closed Lab Activity 2: Vision & Walking Introduction: Purpose of this activity is to examine how vision and memory combine to influence the control of walking. Suppose the telephone rang and you had to walk across the room to answer it. Then imagine what would happen if the lights suddenly sent out and you were pitched into total darkness along the way to the phone. How would you be affected? This lab will answer the question by simulating the time and distance to get to the phone. Task: The task is to walk to targets that are 3, 6, or 9 m away from a starting position, under three different conditions: 1) the subject walks with eyes open but looking straight ahead, not down on the floor; 2) the eyes are closed immediately before walking; and 3) the eyes are closed and the subjects waits 20 seconds before walking. 1

2 Procedure: Use the masking tape, mark a starting position on the floor with an X. Then place a short horizontal strip of tape at each of the three distances from the X along a straight line at 3, 6, and 9 m away. Follow the table in the results section of the lab report for the ordering of trials and distances to walk. The following instructions should be followed carefully, Before each trial the subject should make a careful survey of the distances of the three targets, then give a verbal ready signal to the experimenter. At this point the experimenter will say either, look straight ahead (eyes open condition) or close your eye (eyes-closed conditions). Then the experimenter will tell you which of the three targets is the goal on that trial (near, middle,or far target). In the case of the eye open and eyes closed with no delay conditions, the experimenter will then tell the subject to start to walk. In the case of eye closed with a 20 sec delay, the experimenter will tell the subject to count to onethousand-one to 20, then to begin to walk. At all times the goal of task is to finish with front edge of the right foot on the goal line. Measure the subject s walking accuracy in terms of the absolute distance from the target. Always use the front of the right foot as reference for determining the error distance from the target. Results: The absolute error for each trial should be recorded on your individual data sheet following questions sections of this lab report. Individual Raw Data Table Trial Target Condition Absolute Error 1 Open 9 m 2 Closed/no delay 3m 3 Closed/delay 6m 4 Closed/delay 9m 5 Open 3m 6 Closed/no delay 6m 7 Closed/delay 3m 8 Open 6m 9 Closed/no delay 9m From the results recorded on your individual data sheet calculate your mean performance error in each of the nine different conditions. Record this data in following table. Individual Summary Table Target Open Closed/no delay Closed/Delay 3m 6m 9m 2

3 Activity 3: Sensory Versus Motor Response Set Using a Auditory Start Signal Purpose: The purpose of this experiment is to determine if there is a difference in attending to sensory set versus motor response when reacting to an auditory signals Equipment: Choice and multi-choice reaction time apparatus. Procedure: All the subjects will be seated and positioned in front of the choice or multichoice reaction timer. Depress the key with your non-dominate forefinger. The auditory signal will be a buzzing sound. Sensory set condition. You are to attend to the auditory signal. React to the auditory (buzzing sound) by lifting your forefinger off the key as fast as you can. Response set condition. You are to attend to lifting your forefinger off the key and when the auditory start signal is presented as fast as you can. The experimenter will inform the subject prior to each trial what they are to concentrate on: a) sensory set (e.g., on this next trial you are to concentrate on auditory or visual signal ) or b) response set (e.g., on this next trial you are to concentrate on lifting your forefinger off the key as fast as you can ) Data Collection. You will perform 10 randomly presented trials (see table 1) involving 5 trials per conditions. The experimenter will record each response in msecs on the following table. Individual Data Form Trial Score 1. SA 2. RA 3. RA 4. SA 5. SA 6. RA 7. RA 8. SA 9. RA 10.SA SA = Attend to the auditory start signal RA = Attend to lifting your forefinger off the key when presented the auditory start signal Average Mean Score for SA & RA SA Mean RA Mean 3

4 Activity 4: Visual Abilities Introduction. The visual abilities of static visual acuity, depth perception, contrast sensitivity, are necessary in performing many hand-eye or eye-foot ballistic movements such as catching and hitting. Also, the text indicates, vision plays a role in controlling many voluntary motor skills such writing, prehension, walking, avoiding objects during locomotion and playing table tennis. Purpose: The purpose of this experiment is to assess various visual abilities, that is, visual acuity, depth perception, and contrast sensitivity. Equipment: Stereo 2000 Vision tester, depth perception box. Procedure: Not in any given order with the aid of a partner, lab assistant, and instructor assess the following visual abilities; 1. Static visual acuity or 20/20 vision. Use the Stereo Vision 2000 Tester to assess your far and near static visual acuity. Record your level of static visual acuity on the form below. 2. Contrast Sensitivity. Use the Vision 2000 Tester to assess your far contrast sensitivity. Record your level of far contrast sensitivity on the form below. 3. Depth Perception. Place the depth perception device on a table at approximately eye level. You may need to be seated. Position the subject 15 feet from the unit and place the two control strings one in each hand. Instruct the subject to align the rods from several randomly selected starting position using one eye open (monocular) and both eyes open (binocular vision). Assess monocular depth in both eyes. Data Recording: On the Stereo Optical Far Contrast Tester Form record your near and far static visual acuity, and far contrast sensitivity. 4

5 Record your monocular and binocular depth perception scores in Table 3. Left Monocular Depth Table 3 Results of the Various Visual Abilities Right Monocular Binocular Depth Contrast Depth Sensitivity Visual Acuity Lab Questions: 1. Researches have found that eyes open across the various stances should be better than eyes shut? Do your results support these assumptions? Explain your answer by using your data as support. This activity demonstrates the importance of vision to prevent falling. How might one use vision training to prevent fall in the aged population? 2. Discuss the effects of visual memory on your ability to walk normally? (Did you accuracy change when you eyes were open as compared to when they were closed? Compared to immediate to that of delayed? Compared to 3m to 6m distance? What were the reasons for the differences? We register and hold sensory information to perform any motor or sport skill. How does this activity related to developing a motor or sport skill especially with the very young and aged patient or student? 3. According to the text, does faster reactions occur under sensory or motor response set condition? What were your results? Do they support or not support the contention that sensory set is about 20 msec faster (see pages 433 & 434 of the text) than a motor set? How might this activity be important in performing a motor or sport skill? 4. Did you have normal static acuity and normal contrast sensitivity? What is depth perception? Did you find a difference between your left and right monocular depth vision? Near and far visual acuity? How do these common visual abilities related to performing an object control motor skill such as catching or in a sport such as Baseball or Softball? 5