Applicability of Action List

Walked sister through the list of actions yesterday. Shes a qualified occupational therapist, so I took the opportunity to view the applicability of the motions of actions from a "medical" perspective.

Notes from the review were:
Anything that moves below the elbow are harder to perform accidentally. Furthermore, it appears there is a trade-off between accidental activation and ease to perform the action.

Complicated movements occur at the distal joint (I.E. joint furtherest from the central line of the body). Proximal joints (I.E. elbow, but normally would be shoulder as well, but the distinction is not needed to be made for the purpose of this project) are more deliberate because of limb movement.

The proximal movements are easier to perform because they only have 2 two movements (I.E. flexion - inward and extension - outward), but also hard to iniate because it take more energy to perform the action.

This contrasts with wrist movement. The wrist can perform flexion/extension, and also, ulnar (little finger) and radial (thumb) deviation. This deviation is initiated in the forearm but presents at the wrist. It is defined by which joint goes over the dorsum (back) side of the alternative. For Example, ulnar deviation is a anti-clockwise of the wrist.

There is a further distiction between gross and fine movements. Gross movements use the most energy, are the most distinguishable. Talking to Sal about the movements from my point of view she agreed that first time users would find proximal movements easiest to perform.

From this discussion a classification method for the actions was created. The categories are based upon the type of task that the actions perform. The classification is different for gross and fine movements.

Fine Movements, are either easy or complex. Which relates to basic tasks and fine-tuning tasks respectively. These actions are mostly distal movements. Basic tasks are the commonly used functions, such as play, pause, next, and previous. Whereas, Fine-tuning tasks refer to the task which need fine-tuning, these are commonly based on a continuous scale. These include zoom level and play speed. That being said the task still need to examined using the same categorization methods.

The Gross movements, contrasting to the easy/complex classification, were based on a scale of 0 to ten representing their ease to perform (0 = easy, 10 = hard), which is assumed to be a measure of possibility to accidentally perform. These gross movements are generally proximal movements. These gross movements relate to tasks which are prone to error, that is to say the tasks which if accidentally performed, cause big usability problems, (I.E. mode switching).

The Movement Categorization results in thus;

• Easy Fine Motions - Basic Tasks
• Swipe right or left
• Roll Select
• Pitch Select
• Double Swipe
  
• Complex Fine Motions - Fine-tuning Tasks
• Roll
• Pitch
  
• Wipe Eye
• Sun Rays
• Proximal Motions - Error prone
• Reel it in - 0
• Swipe Roll - 2
• Duffman - 3
• Make it so - 5
• Reel pitch - 8

Another point raised during the examination of the movement is the idea of locking movement. Such as for roll select, does the function keep accelerating after an action or just act discretely.