Lecture 3 - Human Sensory-Motor System

Question 1

Consider the use of 2D screens for 3D movements. What visual queues are available to perceive depth on 2D screens? Which queues are missing?

Answer 1

Available:
- linear perspective
- occlusion
- shadows
- texture gradients
- relative retinal img size
Missing:
- stereopsis (instead of vision with 2 eyes - just 1)
- motion parallax (due to head movements)

Question 2

What is an alternative to using 2D screens for 3D movements and what benefits does it provide?

Answer 2

Alternative: head mounted display
Benefits: allows for stereopsis + motion parallax

Question 3

What is augmented feedback and at what time points can it be provided?

Answer 3

Augmented feedback is sensory information that cannot be elaborated without an external source (aka. external feedback). Terminal feedback is provided after task execution. Concurrent feedback is provided during task execution.

Question 4

For simple tasks, concurrent feedback has been suggested to be possibly problematic. Why?

Answer 4

The Guidance Hypothesis claims that concurrent feedback could lead to dependence and thus no retention. This has actually been proven.

Question 5

Give an example of visual error feedback and its advantages and disadvantages.

Answer 5

Superposition
\+ spatial learning
\+ intuitive
- needs focus on display
- can develop dependence (motor control depends on vision)

Question 6

Give formula for θ_error.

Answer 6

θ_error = θ_current - θ_ref

Question 7

Give formula for θ_shown.

Answer 7

θ_shown = θ_current + θ_error*gain
θ_shown = θ_ref + θ_error ( 1 + gain )

Question 8

What are the 4 types of feedback modalities?

Answer 8

1. Visual
2. Auditory
3. Haptic
4. Multimodal

Question 9

What are the benefits of visual feedback?

Answer 9

• intuitive, straightforward

- spatial learning

Question 10

What are the benefits of auditory feedback?

Answer 10

• no focus on display, free capacities

- temporal learning

Question 11

What are the benefits of haptic feedback?

Answer 11

• direct

- spatial AND temporal learning

Question 12

What are the benefits of multimodal feedback?

Answer 12

• intersensory facilitation

- reduced cognitive load

Question 13

What should well-designed concurrent feedback do?

Answer 13

• prevent dependency
• facilitate task relevant error correction
• exploit modalities
• consider skill level