1. Sensory Contributions to Skilled Performance
Chapter 3

2. Objectives
Explain the contributions and limitations of a closed-loop model of movement control
Understand the various ways that sensory information is used in movement control
Discuss the various roles of vision in movement control
Understand how sensory contributions to movements are part of a conceptual model of motor performance

3. Preview
How is a rugby player able to watch the ball leave a teammate’s hand with a few tenths of a second of viewing time and realize she must turn her back on the ball and cut sharply in one direction to catch it?
She predicts the ball’s flight correctly, visually focuses on it, times the ball’s arrival into her hands, and compensates for other external factors by grasping the ball with two hands.
(continued)

4. Preview (continued) How is so much accomplished in such a short time?
How are corrections made during skilled performance?

5. Overview
Processing vast amounts of information quickly and accurately and making effective adjustments as needed
Processes that allow performers to detect patterns of information in the environment and use the information to predict future actions
The neuromuscular system, the conceptual model of motor performance, and principles of visual control as they relate to movement

6. Exteroception
From the environment
Outside of the body
Highly visual

7. Proprioception
Information that comes from within the body, largely from the muscles and joints

8. Interoception: From Inside the Body
Kinesthesis—Sensory information coming from the motor system that signals contractions and limb movements
Vestibular apparatus—located in inner ear; information about balance, posture, and orientation
Muscle spindle—located in skeletal muscle; sends information about muscle length to CNS
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9. Interoception: From Inside the Body (continued)
Golgi tendon organs—located between muscle and tendon; provide information about force in the muscles
Cutaneous receptors—located in the skin; detect pressure, temperature, and contact

10. Closed-Loop Control System
Involves the use of feedback and error detection and correction processes to maintain the desired goal
Used to control slow and deliberate movements
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11. Closed-Loop Control System (continued)
Good for detecting slow movement
Not good for explaining rapid movement
Does not account for discrete tasks
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12. Closed-Loop Control System (continued)
Comparator—error detection
Executive—brain; determines actions to take to reach goal
Effector—carries out decisions
Feedback—provides information on current state

13. Open-Loop Control
Response selection and response programming require considerable time and attention.
In the closed-loop conceptual model, corrections occur a few hundred milliseconds after an error occurs.
The error signal is processed in the stimulus-identification stage.
(continued)

14. Open-Loop Control (continued)
A movement correction is chosen in the response-selection stage.
Modifications to the movement are organized and initiated in the response-programming stage.

15. Compensations for Muscle Movements
M1—monosynaptic
Most rapid, unconscious, one synapse, little environmental impact, inflexible
M2—polysynaptic
Longer muscle, adjusts more than M1, higher-level function, knee-jerk, sensory, can’t modify once begun
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16. Compensations for Muscle Movements (continued)
Triggered reaction
Wineglass effect, learned, conscious, cutaneous receptors
M3—voluntary reaction time
Voluntary; affected by instruction, anticipation, and stimulus responses; supported by Hick’s law

17. Visual Systems
Focal—Identifies objects in center of visual field; is conscious and affected by light
Ambient—Detects orientation of body in environment; is nonconscious and peripheral

18. Optical Flow
Detects movement of patterns of light from the environment
Perceives motion, positions, timing, stability, velocity, and direction

19. Vision How does vision affect balance?
Visual dominance—visual information dominates information coming from the other senses
Visual capture—visual information attracts a person’s attention more easily than other forms of information