Assignment 4
Question 1
The two most difficult instructions to follow would be:

   
7. "Rotate point of contact between I-affector and object, about axis defined by line passing through points of contact of M and T affectors (with object), by an angle such that P-axis lies at perpendicular distance of 'r' from 'source point'":


   The task of the rotating the pen in 3D space is a high-precision task and requires constant feedback from sensors coupled with rapidly solving the equations to convert the sensor data to motor actions.
   
13. "Applying pressure of 2psi, along -ve Z-axis - trace locus defined by image/characters to be written on the plane of the paper, using Move function for each image/character."


   Tracing a given locus on the paper with a pen is a task requiring very high dexterity and even adult humans, which are experts in this task, perform significantly worse without visual feedback from the eyes. Therefore, this task would be extremely hard for the robot.

Note that these are also two of the six steps which require manipulation of the pencil and not the hand. Manipulating the robotic hand should be easier for the robot than manipulating an external object, because the robot has a lot less control over the external object.
Question 2
The explicit knowledge of the robot might be the directions it has to move the affectors to grab the pencil, to lift it and the directions of the forces the affectors should apply on the pencil to keep it steady. The implicit knowledge consists of the precise magnitude of the forces and the velocities of its affectors. 

The sum of the forces of the two same-side affectors is the same as the force of the isolated affector. Therefore, the force of the isolated affector doesn't need to be specified separately. Thus, it can be "chunked" with the other two forces.
Question 3
Human learning probably follows "reward" based processes. Psychologists have known for long that reward is a very strong driving force in conditioning humans. Consider the fire-fighter: he certainly would have tried a lot of different strategies early in his career. But as an expert, he somehow 'knows' which strategy to follow. It is very likely that the fire-fighter unconsciously learned which strategy produce the best results(rewards).